View Full Version : 6.5 overhaul
farmboy1989
07-09-2006, 06:21
Took my truck to a chevy truck garage and they never seen one put out so much white diesel smoke and I had put and brand new injection pump on and a brand new head on one side but he said he located the 2 cyl that are putting out the smoke.My question is, can you overhaul the engine without pulling it from the truck? I have heard taht you can drop the front differential a couple inches and then you can get the pan out? Any other tips or tricks to overhauling this motor? Also if you have overhauled one I'd like to hear of your experiences. Wheres the best place to buy a kit to overhaul it?Diesel direct had a master kit for 725 or 735 I think and it was supposed to be all american made U.S. Army grade parts. I want to put new pistons in just in case one of them was losing compression somewhere. Also when i replaced the head I found a burnt
valve on one cylinder, so could this have taken the temper out of the rings and the piston?
john8662
07-09-2006, 14:30
White smoke...
The mechanic that said the two cylinders were smoking, how was this determined? I'd suggest a full compression check then you'll know what you're up against.
Perhaps you have a few bad (contaminated) injectors from the recent head replacement, or a head gasket that didn't seal and has actually blown again due to deck imperfections or something during the install, etc.
You can't rebuild an engine in frame.
Remove the entire longblock from the truck and put it on an engine stand rated at 1000lbs. or more (preferred 1500 lbs. +) and take it apart from there.
You'll likely find out that the engine needs to be overbored anyways, so this will need to be determined before ordering any parts like replacement pistons.
Take it apart, and measure what you can, that way you know what you have, then take it to your local engine machine shop for their opinion of what needs to be done.
farmboy1989
07-09-2006, 19:44
When i had the head off there was no ring groove at all. And the mechanic had the manifold off of one side and ran the truck and he located the missing cylinders. I am not losing water and I have no pressure in the cooling system and I dont have water in the oil.Injectors are like new and have been cleaned and checked for popoff pressure and spray patter and were good and the mechanic moved them around and it still smoked on the same 2 cyl.How hard is it to pull the engine?
john8662
07-09-2006, 20:31
I still vote for a compression check, the replacement head could still be no good. You really need to find out exactly what the problem is, helps to resolve what ailes the engine in the end.
It's not the most difficult thing in the world to pull the engine. It's probably best if you have the mechanic pull and re-install, unless you have the time and the tools to do the work (aka, engine hoist, etc.)
The most difficult thing in the world would be... women!
J
farmboy1989
07-09-2006, 20:40
Replacement head was brand new out of clearwater. Engines are nothing new to us as we farm and overhaul a couple tractors from time to time.It smoked this bad before the new head so somthing is wrong with the rings i imagine. As far as engine skills and tools, we are resonably equiped and have a lot of tools. We also have an engine hoist.The thing is that i dont have the money to have the mechanic do it. So i have to do it myself.
Hi there
I just finished doing a 6.5 so all the gory details are still fresh in my little pea brain.
Getting the engine out is no biggy.
Drain the coolant as you did to do the head. unhook all power from batteries.
Get the radiator out along with all the accessories off the block.
Pull the exhaust manifolds and turbo off to give you some working room.
Auto trans?? remove the lower bell housing cover and remove the flex plate to convertor bolts and slide the convertor back as far as will go by hand.
Get the starter off and undo the tranny to block bolts.
The ones on top can be a tad nasty as the fuel lines are mounted there. There are 6 bolts same as all chevy V8
Remove the two long front mount bolts. Unhook the oil cooler lines. These use a snap clip. use a small pick and remove the clip and the lines will slide out. The clip is an E clip type
Unplug all the electrical lines at the rear of the engine.
The 6.5 has lifting hooks on the drivers front and the passenger rear that work sweet to lift the little beastie.
That should about do it accept for a ground wire on the pass head in the back that will be easier to get to after the engine is slightly forward.
Double check the thing for any other goodies still hook up and lift it out.
OH BTW I used a pair of Clearwater heads on my job and they were top notch quality. I took a couple of the valves out to see their work. SWEEEEEEEEEEET
RC
Did anyone think about the IP??
if its toast the engine may be fine. Do a compression check first.
If the pump has a couple bad plungers it could be the culprit.??? Just a thought.
farmboy1989
07-10-2006, 10:35
Injection pump is brand new and it is a 5sp. manual tranny. What will this change when i go to pull the engine?
farmboy1989
07-11-2006, 20:03
Mechanic said I could pull the pain with engine in frame and I didnt have to drop differential. This sounds like a good option.
ronniejoe
07-11-2006, 20:19
Mechanic said I could pull the pain with engine in frame and I didnt have to drop differential. This sounds like a good option.
Your mechanic must be superman...
I tried hard to remove the pan on mine without dropping the differential two years ago to fix a leak... Couldn't be done.
It seems to me I read about some one replaceing the pump and they got two of the injection lines mixed up .It sounded alot like your problem.Could this be ?
farmboy1989
07-11-2006, 20:35
He said they could do it without dropping the diff......i mean it wouldnt seem that bad if i had to drop it down a little.As far as injection lines, they were all traced and they are all on correctly. I think im going to replace the rings and the bearings in the bottom end and the oil pump and call that good.If she runs 100,000,that'll be plenty for me. Im just 16 and paying for these projects are tuff.
Houdini is more like it.
The diff has to come out to drop the pan.
Yank the engine and be done with it.
farmboy1989
07-12-2006, 05:25
The more I ask, the more I think I need to find out for myself. One says you cant do anything without the engine out. The next says no need to drop the diff. Other says drop the diff. Last says gotta take the diff out. Im so confused. Would it change anything that I have the L65 HO engine with the 5 sp. manual tranny?Who out there has the cheapest crossover pipe. SS Diesel Supply has one for like 68 bucks. Thats the best I have found.
john8662
07-12-2006, 07:34
Yes, it is confusing.
What we're getting at is that your mechanic is dead wrong in thinking he can get the pan off the engine w/o dropping the front differential a little bit, or lifting the engine off it's mounts. Something tells me he hasn't worked on many 6.5's to really know. It'll end up costing you more labor in time when he has to figure out the hard way on your dollar that he was wrong...
Crossover pipe, don't worry about one of those right now, get the truck running correctly, then concentrate on the upgrade parts.
So.. How about that compression test, with some concrete numbers?
farmboy1989
07-12-2006, 08:19
Yet to get the compression test done, hope to do that within the next couple of days.I am doing the overhaul myself. The mechanic was a Chevy mechanic and all he did was work on 6.5's.Maybe he was dropping the diff slightly, i dont know for sure.Crossover pipe is not an upgrade. It is rusted out where the clamp goes so i am going to put a new one on that is mandrel bent, mine is dented also so a new one should help.What is the for sure psi i need to make it run right for compression. I dont care about what GM says in their book because the truck is not new.I watched it run without the manifold and the right side is puffing on 2 and 6 very bad , number 4 a little and number 8 not at all.
john8662
07-12-2006, 08:50
By puffing, are you getting a smoke out the intake ports while watching this?
There is a port between cylinders 2 and 6 and 3 and 5, which is an EGR port that is used on EGR engines, the heads are the same, just the port is blocked by the intake and gaskets on HD engines (yours). Is the smoke coming from these, because that is normal (with no intake manifold installed of course).
I'd hope you're only observing the running of the engine with only the upper intake piece removed, rather than the lower.
farmboy1989
07-12-2006, 10:29
Upper intake that goes to turbo is removed. Lower is still on the engine. No smoke is coming out the intake. I have the exhaust manifold removed that is where all of the smoke is coming from. It is a non egr engine, the L65 HO for the heavy duty trucks.EGR ports are covered because I do have the correct intake gaskets on the truck for the engine.What makes no sense is that I was told I was lacking in compression on those cylinders and the heavy smoke suggests that, but i have no blow by at all. I always thought that if your rings were bad enough to lose compression that you would have excessive blowby.I removed the oil filler cap, the dipstick, and the breather that goes into the right side valve cover, and still no blowby. Could it be a possibility that the engine got hot, and took the temper out of the compression rings on that side or somthing like that? The head is brand new out of clearwater, but even after i put the head on and the valve problem was fixed, even though it runs slightly better, it still runs the same way and continues with the excessive smoke.Cylinders looked extremely good with no ring groove when i had the head off.Pistons all looked decent also. Am I missing something here or what?
if it was not smoking before the head was replaced it sounds like it could be a valve seal problem to me
farmboy1989
07-12-2006, 19:52
It was smoking before the head was replaced and it it still smoking now.
Jim Rizos
07-13-2006, 20:21
We are in a similar situation - 6.5 with both heads off (with cracks) -ordered new ones and am wondering what else should be changed at the same time. Vehicle is a 1994 Sub with 160K miles. Cylinders look good -original cross hatch hone marks still visible and no compression ridge. (Oil was changed every 3,000 mi.(mostly Mobil 1). Does anyone have a list of A-Z most critical (or wisest) to least critical things to change at this time?
Thanks very much.
Jim
94 Sub 160K
I just finished a 94 Sub with a 6.5
If the decks are in goof shape just drop on a set of new heads and screw in some fresh nozzles and plugs and you should be fine.
farmboy1989
07-14-2006, 10:30
If it wouldnt be too much trouble for you, while you have the heads off I think I would rering it. I got into that trouble with mine when i put the new head on and didnt rering it and now i have to tear it apart again so all my time was wasted the first time around. You could still see cross hatch in my cylinders and no ring groove but I guess the rings were still bad I guess. Still learnin from my mistakes.
farmboy1989
07-16-2006, 11:01
Checked the bad sides compression. The weak cylinder maxed out at 320 and the other one that was sposed to be a little weak was around 350.Any advice?
What are the good cylinders running??
farmboy1989
07-16-2006, 19:57
Best on that side was 360, have a mechanic that is gonna come look at it but he thinks that 320 is sufficient and that he has had a handfull of bad reman pumps. He works on 6.5's for a living.
Jim Rizos
07-18-2006, 07:14
[Thanks, Robyn, that's what we'll dio.
QUOTE=robyn]I just finished a 94 Sub with a 6.5
If the decks are in goof shape just drop on a set of new heads and screw in some fresh nozzles and plugs and you should be fine.[/QUOTE]
The compression sounds good it sounds like you have two crossed injection lines
[Thanks, Robyn, that's what we'll dio.
QUOTE=robyn]I just finished a 94 Sub with a 6.5
If the decks are in goof shape just drop on a set of new heads and screw in some fresh nozzles and plugs and you should be fine.[/QUOTE]
Always use new head bolts when changing heads.
farmboy1989
07-19-2006, 05:25
Decided to bite the bullet and do an overhaul anyways.Still think diesel direct has the best price. 735 with pistons and 395 without. Anybody found any better prices?
There are several outfits selling parts that have decent prices.
I would wait untill you get it apart and buy when you can see what you need. First order of business is get the beastie out and apart.
have the block hot tanked and magnafluxed first to make sure you dont have any cracks. Do the crank too.
At this point you can mic the cylinders and the pistons and see what you have to work with there. Check the crank and see what sort of shape its in. If your crank is in good shape a new set of Bearings will most likely do the job.
Now these suckers came with all sorts of combinations of bearing sizes. when you take it apart keep the bearings in the order they came out and look at the back side of the shells. The shells will have a number on them and if they are GM stockers they may also have a size notation. GM mixed and matched sizes to select fit these engines.
You could have std rods std mains or undersized rods and std mains or undersized mains and std rods. The sizes are in metric so dont let that fool
you.
Mine had .005" undersized mains but I used a set of stds on it and the clearance was within spec.
Check the pistons and if they look good and the cylinder walls are ok and not badly worn a quicky hone and a new set of rings will do.*** A note here*** the pistons may have a hard black coating on them, DONT USE A POWER WIRE BRUSH TO CLEAN THEM. When you are ready to reassemble BE SURE TO CHECK RING END GAP some rings sets are wierd and will be out of spec. I had to file all the #2 groove rings on mine as they did not have enough gap.
Check the cam. If the lobes are good and not galled and have just a shinny path where the roller runs you can reuse the cam but replace the lifters. So many times the lifters will fail to pump up after being disturbed.
More later as you get along with this project.
Mine is still very fresh in my mind as its been only 2 weeks since I got it back on the road after a complete overhaul. I had it down for 2 months while we gathered parts and pieces and worked on it.
Good luck
Robyn
farmboy1989
07-19-2006, 10:03
We are farmers and do farmer overhauls.Having the block checked is probably not going to happen as if i would find out it is cracked I would just junk the truck. It didnt have blowby or water in the oil or a pressureized cooling system so I think im in good shape there. Unless the crank is scored up bad im gonna leave it in there and unless it plastigages really bad , i will prolly just put back in the same size that was in it.This cant be an endless money pit and you got to have a stopping point somewhere. Pistons may clean up alright but one will for sure be replaced because when the valve went out it beat out part of the dome.The lifters were all working well as the gm mechanic ran it without valve covers.While I dont think entirely that my problem is 100% compression related, I think it is contributing to the problem and the rest I think is the pump.Im not building it to drag race, its just gonna be a farm truck and for a 16 year old thats all I need.
I think you have two of the lines crossed on the injection pump
You asked, "Decided to bite the bullet and do an overhaul anyways.Still think diesel direct has the best price. 735 with pistons and 395 without. Anybody found any better prices?"
If you want to save some $$$ and make your engine 18:1, machine off .030 - .040 from the top of the piston crown and have it heat coated. To do this you will need good condition stock compression pistons. Your original pistons may not be a good donor. I did this and am running them now. Cost me about 200 for the machining and heat coatings. I got 18:1 pistons for < 200$ rather than shell out 700+ for just pistons.
However, I started my rebuild with a good long block that I picked up for pennies. I did not shop for a rebuild kit. If I had to buy a rebuild kit I would go with the $735 one.
One more piece of advice. Find it in your rebuild budget or make some room to get the rotating assembly balanced. The engine will behave like a gas engine. Smooth and quiet unless you drive with a lead foot.
farmboy1989
07-20-2006, 15:15
Lines arent crossed, all of them have been traced down and they all go the appropriate cylinder.
I thought for sure thats what was wrong.Did the problem get worse after changing the pump.
farmboy1989
07-21-2006, 05:32
Well we talked to the guy that had the truck and he thought the pump went out on him so he traded it off as non running. The chevy dealer put a pump on it and it didnt run worth a darn and smoked a ton so they sold it off. I found a bad valve on one side and the lift pump wasnt working. But after fixing both of those it hasnt changed the way it runs much.It has been timed too.
I wouldn.t pull it out till I figered out what.s wrong.I think something with the pump.The lower end sounds all right.
farmboy1989
07-22-2006, 07:15
Well we think we might pull the pump and have it checked at the diesel shop and if i find out its bad i am going to be infuriated because my luck it's a rebuilt or somthin and gm wont warranty the rebuilt pumps.Im at a loss right now, just chasing ghosts. I mean I'd like to think im a decent diesel mechanic but this truck has made me look stupid.
Hello again
Well dont feel bad, I have be wrenching professionally for over 30 years.
Started out working for my dad when I was young and branched out and did my own thing. Some of these critters will make the best of us look like rank amateurs.
Lets look at what you have already done and rule out the obvious and whats left must be the culprit.
1 replaced one head, so thats not it.
2 checked compression and its ok
3 timing is ok
4 General mechanical conditionis acceptable
Well now whats left?
The engine should run ok if the fuel system is working properly.
Have you checked all the injector nozzles to see what the pop pressure and spray pattern looks like?
If you have a few bad nozzles it wont run for sour grapes.
Dribbly nozzles or low pop pressure and poor spray pattern is overlooked many times.
If you havent had the nozzles checked do it. Its not costly at all to have them checked and may very well be a big issue.
Even the best engine around will not run properly with a lousy set of nozzles.
what happens is the fuel my squirt in in a stream at low pressure rather than a mist at very high pressure.
Next is the pump, you have already stated that you are suspect of the pump, so these are your options.
Process of elimination is the only way to fix these things. If you are not wanting to pay to have the nozzles tested swap the nozzles from the bad running cylinders over to one that was running well and see if the trouble follows the nozzle. If it does, Bingo you have found your gremlin.
Thing is that when these nozzles start to go away usually the whole set is worn out.
keep us informed
Robyn
Farm Boy
I just went back through and reread this entire thread on your problem and I see no mention of the injector nozzles.
Do yourself a favor and scrounge up a couple good used nozzles and drop into the two really bad cylinders and I'll bet you the issue will go away real quick. If this be the case get your nozzles rebuilt and enjoy your truck.
Or if you prefer just go ahead and drive it a while after just replacing the two bad squirters.
One thing for sure if replacing the squirts in the two offending holes does not fix the issue it really does point the finger at the IP.
RC
There's not a heck of a lot in the IP that's cylinder specific.
I know this has been brought up before and dismissed, but, given all the things you've eliminated, It still sounds like crossed injector lines to me...
DmaxMaverick
07-22-2006, 11:30
One thing that hasn't been mentioned here is the complete valve train.
IF....you have intake valves that don't open enough, the compression while running can be too little to combust the fuel, and blow white smoke. It could be just about any part of the valve train. Flat cam lobe, lifter not pumping up, blocked lifter port, worn out or cracked lifter bore, bent pushrod, bent/worn rocker, broken/bent valve stem (not likely since new head), worn out rocker rack, etc..... All these things can be specific to individual cylinders.
I read the posts, but missed it if it was there. Which cylinders #'s are the suspects?
Quit spinning your wheels trying to chase this gremlin and check the injector nozzles on the two bad cylinders. If they work ok in another hole or test ok then move on. Nozzles are a common item to fail on a high mile 6.2/6.5.
You have already stated that this rig has been messed with by others so me thinks you need to check these areas.
Robyn
Has compression test even been done?
farmboy1989
07-23-2006, 05:08
Injectors are relatively new, have both been checked for spray pattern and pop off and all are good.Yeah we did a compression test. The suspect cylinders are weak (320 on the weakest and up from there, another one of the suspects was 350) but the mechanic I have been talking with says thats enough to make it run decent, he has worked on the 6.5's for a livin since they were new. Suspects are 2, 4, and 6 but when you start to wind it up the other side starts smoking just as bad too. But after you just start it up, within 10 seconds it clears out and smooths out and it doesnt smoke.But when you start to speed it up it starts smoking and misfiring.All injector lines have been traceds and are correct on the pump and injectors have been swapped.All of the valves operate ok on this side as we have ran it without the valve cover here in the shop.If compression was weak then wouldnt it run worse at an idle than at higher rpms?....Ive also heard that reman pumps are junk(nots sure whether mine was a reman or new) and that they were never really rebuilt if they tested alright.
Eng. sound good to run so the IP could be your issue. Low Comp. would make it a little harder to start and run rough when cold. 320 on a few cly. is'nt that bad to run rough at higher rpms.
One thing that hasn't been mentioned here is the complete valve train.
IF....you have intake valves that don't open enough, the compression while running can be too little to combust the fuel, and blow white smoke. It could be just about any part of the valve train. Flat cam lobe, lifter not pumping up, blocked lifter port, worn out or cracked lifter bore, bent pushrod, bent/worn rocker, broken/bent valve stem (not likely since new head), worn out rocker rack, etc..... All these things can be specific to individual cylinders.
I read the posts, but missed it if it was there. Which cylinders #'s are the suspects?
If this were true,would the comp. be lower than the 320? Do diesels ever burn vavles as in gas Eng.?
Well now
The process of elimination is working well.
You have narowed it down now to where the pump almost has to be the culprit. There is one other tid bit that must not be overlooked though.
The "Noise supression harness " This little critter is the short wiring harness that plugs into the top of the IP and is about 6 inches long and has a little black block in it that the wires go though. It plugs into the main engine harness. It will not cause codes to be logged normally but can cause some very lousy running. It filters out electrical noise from the system and if it fails will allow erroneous signals to hit the pump. If this is not the issue then the pump has to be the target. Have you had any codes at all because this issue also sounds like a stepper motor fault (IP stuff)
Hope this helps
Robyn
farmboy1989
07-23-2006, 10:40
Cylinder imbalances were the codes, along with timing code. But those codes were there before the truck was taken to the dealer. But i never got the service engine soon light with any of those codes. What else is a possibility that is wrong with the pump besides the actual mechanics of the pump itself? I replaced the computer in the glovebox already.Is there any way to test these external components of the pump?
are you getting any codes now if you run the engine for a time??
Cylinder imbalance is generally a pump issue if you dont have other issues.
I think its time you have the pump checked by a reputable pump shop that can run it on a test bench and check it out well.
I helped another shop a few weeks ago diagnose this very smae sort or trouble and it all came down to the IP.
Yank it off and get it checked.
RC
farmboy1989
07-23-2006, 15:00
Ive been going through checking all connections at the pump.All seem to be ok.Judging on the tags on the pump i think it is sposed to be brand new.What mechanically could be bad with the pump that at high rpms all cylinders would smoke, and i mean bad bad lots of smoke? Defective pump from the get go?
Supposed too's are sometimesa real PITA.
Yank the pump off and have it run up on a test bench and find out for sure. I have seen some real wierd stuff out there.
You have beat yourself up enough now and its time to find out the straight skinny on this pump.
If the cylinders have good compression and the injectors are good and the pump is good it will run good. Obviously something is amiss. you have checked the injectors and the compression and so it must be the IP.
are u sure the lines on the pump are not crossed
john8662
07-24-2006, 00:11
The "Noise supression harness " This little critter is the short wiring harness that plugs into the top of the IP and is about 6 inches long and has a little black block in it that the wires go though. It plugs into the main engine harness. It will not cause codes to be logged normally but can cause some very lousy running. It filters out electrical noise from the system and if it fails will allow erroneous signals to hit the pump.
I don't think so :confused:
To the best of my knowledge this little critter is there for stopping the IP from receiving interference, but it doesn't cause poor running like Farmboy is experiencing.
Most complain that the failed filter causes "fish bite" where the engine will momentarily cut out while running at a constant speed. This is what mine did, was mostly noticable when driving down the interstate with the cruise one, feels like a bump in the road, or the torque convertor unlocking quickly...
Just my .02
John
yes I agree that is the most common symptom of the suppresion harness failure. BUUUUUUUUUUUUUT with all this fellow has been through here I did not want to leave any stone unturned.
I have seen the harness issue cause other anomalies too.
I really am of the opinion that the IP has some issues. With the compression good and the injectors ok the sucker should run fine. I looked over a 6.5 sitting here in the shop and I know the lines can be mixed up but farmboy has repeated that they have checked and rechecked them. Its got to be the IP.
What about the wiring harness that feeds the pump.
There is a connector that plugs in on the right front of the IP, I am not sure exactly what that little solenoid looking item is, maybe the advance, not sure ??
Stinking electronics will drive a body insane!!!!! :0(
john8662
07-24-2006, 11:47
There is a connector that plugs in on the right front of the IP, I am not sure exactly what that little solenoid looking item is, maybe the advance, not sure ??
(
What's your vantage point looking at the pump?
I'd suspect you're looking at the "stepper motor" this is for the timing advance/retard, this motor operates the whole time, and rather quickly.
J
Passenger side of the pump at the radiator end down low on the side.
farmboy1989
07-24-2006, 20:44
Pump is off and settin in Scheid Diesel in effingham illinois. Within the next day or 2 i should know. They are a little busy dealing with tractor pullers right now.I thought 94's and up were sposed to have timing chains?.......Mine just has timing gears inside there the timing housing.
ronniejoe
07-24-2006, 21:50
You're looking at the injection pump drive gears. If your truck has not been modified, there is a timing chain and two sprockets that run the cam shaft at half crank speed. Mounted to the cam sprocket is the injection pump drive gear which meshes with the injection pump driven gear. The driven gear is mounted to the injection pump shaft.
farmboy1989
07-25-2006, 15:50
What ronniejoe said makes more sense to me.Didnt get word on the pump today. They said the other day they are swamped with tractor pullers.:(
farmboy1989
07-26-2006, 16:17
Well,talked to Scheid today. They said the pump was good and looked good on the stand so we agreed we'd stop there. They didnt know where to turn. But when i took the pump off i marked it, and also noticed it was turned all the way as far as it would go in one direction. Seeing this, is it possible the timing chain could have jumped a tooth? This would also contribute to my low compression wouldnt it?
6 and 1/2 liters
07-27-2006, 07:36
you don't have low compression. They run perfectly normal with a couple cylinders at 320
Does the front cover look like its been off recently?
This whole project is really interesting in as far as it has stumped almost everyone here including myself.
You are going to have to wring this thing out very carefully and just keep eliminating potential causes.
The pump should be set about in the middle of its adjustment travel.
The computer will do the adjusting from there.
Retarded timing can cause poor running for sure but I am still at a loos as to why two cylinders are blowing so much smoke.
Look into the timing case and see whats up in there. Check to make sure the timing chain and sprockets are set right and then the gear set.
If all is well there stuff it back together.
Have you checked the crank sensor? They usually work or they dont.
This is begining to sound like maybe a computer issue rather than a mechanical one.
farmboy1989
07-27-2006, 14:57
Well a couple cylinders puff a little possibly because they are a little weak and take longer to warm up. But when I start to throttle up then all the 8 cylinders start smoking terrible.This thing gets as bad as big diesel tractor pullers warming up their tractor before the pull.So if timing is off, that accounts for fuel delivery and opening and closing of the valves and possible loss of compression.Scheid also agreed that this was a possibility. But my dad is dead set on an overhaul and my uncle tells me just do the chain and gears.Oh how so many outside opinions makes my head spin...lol.... Why would it possibly jump time? I have heard of trucks jumping a tooth on the chain and never knew why. Any advice on what I should do because at this point it doesnt hurt anything.
Did this thing ever run right?
If the pump was way out of time it would smoke bad. Also it would set codes.
If you changed the heads due to water problems, the exhaust could be full of water. How long have you run it since?
Never heard of one jumping time by itself.
DmaxMaverick
07-27-2006, 15:13
It's not likely to have jumped time. More likely, the key at the crank sprocket could have sheared, which would explain just about everything. Could also be the crank position sensor is outa' whack in some way.
The two cylinders that smoke at start could be due to lower compression, or no glow plug heat (for whatever reason). If it clears up soon after start, I'd forget about that, for now.
farmboy1989
07-27-2006, 15:25
Nope, she never did run right.Im chasing the problem that 2 chevy dealers couldnt fix. I bought it like this. Yes I did change one head on it but the only reason I changed it was because of a burnt out exhaust valve and worn out guides on that side. The new head really didnt change the way it runs. Injection system was timed by chevy garage but it didnt help and I notice that the pump was turned all the way in one direction which was an indication to me that there is something wrong with the timing system.Anybody replaced the crank sensor? Whats it cost?
sensor is about $50
Its down behind the power steering pump and plugs into the front cover just by the pan rail. One bolt holds it in.
If the crank sensor is bad it should toss a code though.
The little buggers can be a bitch to get out so be prepared to worry it a bit.
I am suspect that someone has done something wierd with this engine as with all you have told us it should run fine.
Robyn
Sounds like it might be smart to pull the timing cover off and verify all the bits are in the right places. Bad injection timing could account for all your issues, I think. If the cam timing was off much you'd have a hand full of bent valves.
Watson .I believe the game is a . foot
farmboy1989
08-01-2006, 14:34
If cam timing wasnt off a ton I would think the engine would have been alright because the truck hasnt run much like this and hasnt been on the road like this. Im trying to bring myself to work on it more but the hot weather is slowing me down.Is it possible when the dearler changed the pump that they could have accidently jumped the gear on the pump a tooth?
I had an experience a couple years ago with a customers truck that has some similarities. Truck needed an fsd but customer wanted entire pump replaced and was in a hurry. I sourced a reman pump locally & installed it. I tried for two hours to time the thing & ended up with pump as far as it would go to passenger side & still setting code for incorrect timing. turned out pump can be assembled wrong & timing will be way off. I took whole truck to supplier & they pulled pump & fixed it. hope this helps.
farmboy1989
08-01-2006, 19:07
TAG, in what way was the pump assembled wrong? I mean i had the pump at a diesel shop and had them check it out on their test bench and it was fine.Well the news for tonight is i got the water pump off and the injection pump gear and cam gear are lined up where they are sposed to be, originally i suspected it off a tooth.How many degrees should you be able to turn the crank before the chain catches the cam and you start turning the cam?
TAG, in what way was the pump assembled wrong? I mean i had the pump at a diesel shop and had them check it out on their test bench and it was fine.Well the news for tonight is i got the water pump off and the injection pump gear and cam gear are lined up where they are sposed to be, originally i suspected it off a tooth.How many degrees should you be able to turn the crank before the chain catches the cam and you start turning the cam?
Now's a good time to just replace the chain. Chain shoud not move more than 5/8". Still even a worn chain should not give you the trouble you are having:( Also check the crank key. Pump and cam lined up. Cam and crank?
farmboy1989
08-03-2006, 14:22
Have not had a chance to check cam and crank alignment yet.Everyones first guess on whats wrong is pump but pump has been checked at diesel shop.I think im ready to look at the other engine 5 miles down the road. But then my luck would be i'd get that one in and then my pump would be bad all along.Dang I wish i had a 4-71 detroit with a supercharger and turbo on this truck.
farmboy1989
08-04-2006, 15:32
I think im ready for a last ditch effort to save this engine. I think im gonna put a new chain and new crank and cam sprockets on this thing. Rockauto has the sprockets and chain for 85 bucks. Anyone know of cheaper?
farmboy1989
08-05-2006, 20:22
Found a worn out chain tonight. I could flop the thing back and forth at least an inch if not quite more than that.I think its time for a few new parts! I am releived to see the worn out chain, I think this may fix the problem. Now when i do get my parts, oh if i could ever remember how to put it back together. LOL, I am forgetting fast.
I found a place in Columbus, OH that has used 6.5L pulls, I bought one with approx 40k miles complete for around $2000 including core... most are low mileage....would probably cost you a few hundred for freight.
The motor I got was a replacement engine that was installed in a van then pulled for cummins conversion...so it had mech inj pump, so I had to swap front cover, injector pump and all front accessories(it was a van motor and my pickup had different accessory locations...but i now have a good strong motor with a few nights of work to get it swapped over and installed...
farmboy1989
08-06-2006, 19:18
Well my chain isnt as bad as I thought according to measure ments.......5/8 of an inch or so slop.I dont know what to do. The used engine that I found thats good is 1500 bucks and 5 miles away. I may be able to get it for even less if im interested.
With all that we have gone through on this thing I am still not convinced that your engine is bad. It would be a real bitch to get this other engine and have the same problem when you get all done.
I really believe you need to diagnose the trouble before making any rash decisions. The PCM may even be the issue here and not hardware under the hood.
farmboy1989
08-06-2006, 21:07
Is the pcm the cylinder object on the back of the pump with the wiring coming out the back of it ? How can i check if its good or not? Is it possible to do so with an ohm meter or the like?I had the pump checked. But maybe the cant check those? I replaced the computer in the glovebox already.Im trying everything possible to diagnose the trouble here. I mean im already doin better than 2 chevy garages.
ronniejoe
08-06-2006, 21:35
pcm = Powertrain Control Module
It's the computer that runs the engine. It will be located behind the glove box.
farmboy1989
08-06-2006, 21:47
Ok then, i have replaced the pcm. Fill me in on what some of the external accessories on the pump are then. Also if this helps, the pump timing was advanced as far as it would go by the twist of the pump, this was done by the chevy dealer. It idled better and started better after they did that but there just wasnt enuff advance there.What would a bad stepper motor act like, or would that be tested at the diesel shop?How about somthing in the pmd?
Bornready6.5
08-07-2006, 10:15
Sorry to jump in here this late in the game, but what number IP do you have? If the previous owner may have installed the wrong pump.
94 1 ton's require the 5068 IIRC. If you have a 5521 pump or any other number...it would most likely run like your describing.
I went back and read the entire thread, and didnt see anyone mention this, so forgive me if this was already suggested.
farmboy1989
08-07-2006, 14:01
Yup...its got the right pump, a 5068, verified right by chevy garage.
A bad stepper motor will make it run like crap. It will misfire and toss out copious quantities of foul smelling smoke (Blue to white)
I still think the pump is garbage.
The thing should be tossing codes after you rev it up a bit and let it run.
See if you can scare up a good used IP (Known good) that you can borrow and stuff it on the rig and do a test.
This thing is not mechainical I am sure of it. I won't toss trash at whoever tested the pump but I think it has issues.
I have seen these things drive folks nuts and it all boiled down to a pump that was toast.
farmboy1989
08-07-2006, 18:07
Does the stepper motor control the electrical advance of the timing? I dont have access to a good pump.The place that tested the pump said it was lookin good on the stand. But wouldnt that just be mechanical output and have nuthing to do with electronical timing?Man what you describe with the stepper motor is a lot like im experiencing.
farmboy1989
08-07-2006, 21:44
What would an optical sensor on the pump do if it acted up also? What symtoms would it give?
The thing will usually just quit.
An optical sensor failure will set codes too.
The computer has to see input from the optical sensor if it misses a certain number of counts it sets a code and then if things get worse it will shut the engine down. I am not of the mind that you have an optical sensor issue.
I still think this is a pump issue.
There must be someone around your area that has a pump you could try.
I would call Kennedy diesel and talk to John and see what he says.
If you were close I would recommend the guys here in Portland but thats just too far.
I dont know if JK does rebuilds inhouse but do call him.
farmboy1989
08-08-2006, 14:20
Talked to the pump shop and they said they checked everything on the pump just short of tareing it down.They said they have had some instances of which the pump tested good but the pump was junk on the truck. This possible here?
I am very certain that you dont have a mechanical issue here. My picky finger is pointing at the pump. The computer could be at fault but me thinks PUMP. This is why I am saying swap it temporarily to see if this is the issue.
Almost anything is possible with these beasties. The wiring harness is also suspect on high mile engines. Be sure the engine harness does not have issues. There is a complete harness that stays with the engine and plugs into the pump and all the sensors and then plugs into the firewall harness in the rear.
Check this stuff carefully.
Robyn
farmboy1989
08-08-2006, 19:36
New gaskets and new chain are on there way.Once installed I will reassemble to see how it runs and then the plan is to call the local chevy mechanic that works on all the 6.5s and let him look at it.I asked him to do so earlier but he wanted it back together first but i decided to tare down.
farmboy1989
08-09-2006, 06:20
He also thought injection pump. I dont know how im gonna get up the nerve to buy another pump if this one is bad on the truck.Maybe he'll find somthin else.But first step was eliminating mechanical timing.Thats why the chain is going on.
farmboy1989
08-10-2006, 14:29
Well,got the parts today. While the pump is off, is there any way for mey to check the accessories on it?
Not really much you can do.
These are very complex units and require some special tools to diagnose and adjust stuff.
farmboy1989
08-10-2006, 19:02
One side note, the diesel shop said they retimed the pump for me when they cheked it. Does the pump have its own separate timing separate from that of the truck?
One side note, the diesel shop said they retimed the pump for me when they cheked it. Does the pump have its own separate timing separate from that of the truck?
It's all ECM controled. Need to be running and scaned.
If the shop told you they retimed the pump I think you need to get that pump rechecked by another shop before you proceed any further with the work it takes to reinstall it and such.
The pump is a dumb thing. It has to have input from the PCM/ECM to operate. It is a mechanical device that pumps fuel at high pressure and is controlled by the ECM/PCM (computer). There are various sensors on the engine, one being the crank sensor that tells the computer where the crank is and this translates to what cylinder is ready to be fueled.
The pump is rough timed by the adjustment where it mounts and the rest is all electronic. The adjustment is done internally via the timing stepper motor.
Get your pump rechecked.
Robyn
farmboy1989
08-15-2006, 15:49
Put the new chain on last night and the timing cover too. The new chain is A LOT tighter than the old one .At least i'll be able to eliminate the chain and crank sensor now.
wait, how did this end? I was reading a good mechanical detective story, but someone tore the last couple pages out of the book!
farmboy1989
02-10-2007, 22:47
Well, I never did finish it did I? I put everything back together and hoped for the best. I had the truck retimed. The best thing I did for it was put a on/off disconnect switch on the ect sensor.The full advance of timing and added glow times is the only way im able to start in the cold illinois weather right now. I have also added a manual glow plug switch that I use when I need it.While this truck is far from a new one and I could still stand to overhaul the engine, it does run pretty good once it is warmed up and it doesnt burn any oil.In temps of 15 degrees on a cold start right now it fires right up and misses and chugs really bad. It also smokes like a steam engine too,tons of smoke. But give it 5 mins to set there and idle and all these things are gone and you're ready to roll. At this point I am looking at installing an intake preheater to help get rid of some of the startup smoke and get the engine running smoother quicker.Engine seems to be good and strong still.Havent had a problem with it.If you have any other questions feel free to ask.
gherrell
02-12-2007, 21:03
....If you have any other questions feel free to ask.
So are you saying that you got it fixed? If so, what do you think the culprit was?
I have never heard of anyone having to put a disconnect on the ECT sensor for good cold starting. I would suspect a bad ECT sensor and possibly some bad glow plug connectors based on the chugging when cold...
Would like to hear your thoughts on what fixed the problem...
Thanks,
farmboy1989
02-16-2007, 21:06
Disconnect on ect does help. The ect sensor is new and does work. What it does when I turn the switch off to disconnect is, it thinks its -40 degrees. This makes for added glow time at start up and gives a full timing advance on the injection I believe.It also ups the idle rpm by a couple hundred too. The chugging is based on worn out engine. All of my 60g glow plugs are brand new, controller works, all glow plug wires have power to them. When I manually hit the glow plugs while running I can clear the smoke and chugging up, but I dont make this a practice so that I dont burn out the plugs.Essentially the problem has not been fixed, but rather band aided. I believe the new timing chain made the truck driveable. When this truck starts in cold temps it smokes like a steam engine for probably 5 mins and then the smoke will clear up at an idle. But when I start driving down the road it will continue to smoke until It builds up to about 4 psi boost and then the smoke clears up for good. I am guessing the hotter air and increase pressure in the cylinder gives the necessary heat to clear that cylinder up good. The only thing to fix this engine right would be an overhaul.With the truck warmed up my weakest cylinder, number 2, tested 320 psi. I confirmed the fact that this cylinder was weak because i started the engine without the exhaust manifold on that side and it was the one that was missing.Some I had another one that tested 350 that wasnt as bad but it it did smoke a tiny bit. My strong cylinders were in the 360 range.With all of this in mind the only time my truck has failed to start was when it was 0 degrees, not plugged in, and batteries a little weak. I put the battery charger on it for 5 mins and then it took off.Any more questions?.........I wish sometime I could get a video of it starting to show everyone what this truck does. It would boggle your mind that I can drive this thing, lol.
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