View Full Version : Newbie.....name says it all
I’m new to this forum, so please forgive me if I’m posting in the wrong area. I’ve just bought a ’95 Chevy 1500 Z71 with a 6.5L Turbo Diesel. This is the first diesel I’ve owned that I’d have to work on (in high school I had a VW rabbit that dad worked on, but that was too many years ago). I have a few questions I hope you can help me with.
(1) The service engine soon light comes on intermittently. I noticed the middle electrical plug on the left side of the engine not plugged in. It looks like it goes to a vacuum solenoid and I thought this was the problem, but the light still comes on.
(2) Is it safe to use an engine degreaser and garden hose to clean the engine compartment?
(3) What is PCM?
(4) After driving the truck for a while it felt a shudder…..kinda like it wasn’t getting enough fuel. Not long after that the water in fuel light came on. I think the best bet is to change the fuel filter……is this accurate thinking? And where are the filters?
(5) The ABS light stays on. The explanation I had from the kid who sold me the truck is that numerous mechanics where unable to find the problem and that there have not been any problems with the brakes. I know this is not an engine thing, but I was hoping someone might have some insight into this problem
DickWells
02-12-2009, 20:05
Hi and welcome. You'll get more and better answers to your questions from the more expert members, I'm sure, but here's what I'd do if I were you.
Get your hands on some good reference material. The Helm manuals are out there second hand, and worth what you'll have to pay. Jim Bigley's R&R manuals are great to have. All this assuming that you plan on hanging on to this truck for a while, of course.
You'll have to learn how to change that fuel filter anyway. It's in the valley behind the intake manifold. The owner's manual (hope you have it) will tell you how to do it. The new filter has an integral air bleed on top. There's a petcock up front by the thermostat housing for draining the housing. Oh, heck yuh gotta be there. Anyway, if the filter change doesn't get rid of your skips, start looking at the ole lift pump/oil pressure switch syndrome, as well as checking every blasted electrical ground on the truck. They're all suspect. Don't worry, you get expert at finding them before long.
Don't get me wrong. I loved my 95 Burb so much that I hung onto it after we sold out and started full-timing. Still have it, still love it. They're great trucks, those 6.5s.
Forgot what else you brought up! Keep in touch. You'll get all the help you need right here.
Good luck.
Dick Wells
DickWells
02-12-2009, 20:28
Heck, yes, take a hose under the hood. Keep the water out of the air intake, and don't get too agressive around the electrical connections and the fuel filter. Just the obvious stuff.
PCM? Power Control Module, as far as I know. I know it as the ECM, which is located in front of the glove box. Just slip the door off by bending the circular tabs away from their slots and tilting it out until you can lift the hinges up and back. I would think the only reason you'd want to get in there for the time-being is to check those connectors in there. I never had to do anything but make sure that they were snapped together tightly, but others have found connection problems there. There's another smaller box in there off to the side that's the Vehicle Speed Sensor Buffer if I remember correctly?
Awful thing to admit, but my ABS light has been on most of the time since about 02! Fixed it once by mistake down in Florida by making a panic stop.
It had been on for months. Just slammed the brakes on (with the trailer behind, too), slid to a stop and the light went out and stayed out for about a year. I too, have no braking problems with the Burb. Whenever I put it on the road, I go out and test the brakes for equal application on a gravel road. Still stops the car, and or, car and trailer as well as ever as far as I can see. Don't climb on me, boys and girls, I'll fix it one of these times that I'm home! Yes, the Sierra's ABS works just fine.
You'll get better poop on your 6.5 by tomorrow, I'm sure.
Dick W:)
Sorry DW....forgot to mention that the owners manual is MIA.
So the petcock on the front of the engine is to bleed the pressure in the fuel system?
Additional information….In regards to #4, on the ride home this morning I noticed that the “shudder” happens mainly around 1500-1800 rpm and the truck throw a bunch of black smoke. And as a knee jerk/panic move I put a bottle (yes, the WHOLE) bottle of fuel treatment into the tank due to the fuel in water light. I think the bottle treats 100 gal and my tank is around 352 gal…..will this hurt the engine?
You need to drain the water from the filter. The filter is designed to separate the water. You do not want to run the water through the system, like you might with a gas engine. Fish the hose coming from the bottom of the drain valve on the thermostat housing out and put it into a jar half full of fuel. Run the engine and open the drain. If fuel or water runs into the jar, your lift pump is good. Continue until enough has come out to ensure no water remains in the filter. If the level in the jar goes down when you open the valve, close it immediately. Your lift pump is not working and needs to be fixed. If you allow air into the system you'll have trouble getting it to run again until the pump is fixed. Once all that's done, it won't hurt to change the filter.
To drain the water, your lift pump has to be working. It is suspect due to the "missing", except, the RPM range and smoke point to a problem with the EGR system. Once you get past the water and lift pump, if it still misses, check the EGR valve and ensure the round gasket is in the EGR "chimney" between the upper and lower manifolds. It is often left out.
If the ABS light is on there should be codes stored. As far as I know, the paperclip trick (search on that) won't read ABS codes, so you need a code reader.
Owners manuals can be ordered from www.helminc.com
DickWells
02-13-2009, 18:09
There, that's the info your looking for! I'm 2400 miles from the Burb and the books, plus about 4 years down the road from having worked on it, so I've forgotten most of what I knew about the 6.5. Sorry. I said I still love the thing, not that I knew anything about it. Just enough to be dangerous and wanting to be involved!
DW:)
It is suspect due to the "missing", except, the RPM range and smoke point to a problem with the EGR system. Once you get past the water and lift pump, if it still misses, check the EGR valve and ensure the round gasket is in the EGR "chimney" between the upper and lower manifolds. It is often left out.
I've already changed the fuel filter and, like a true newbie, I attempted to start the truck before getting the air out of the filter housing. I've had a hell of a day fighing with that truck. The engine is now missing at random times/rpms. Will a code reader tell me if the lift pump is bad? Is it possible that air is getting sucked in somewhere. I noticed some fuel around the filter area and I tightened the cap as tight as it would go. I was thinking about changing the filter again to make sure it's not the new gasket.
Is a lift pump the same as a fuel pump? I did buy a Haynes engine manual today, and I didn't see lift pump in the index.
a5150nut
02-13-2009, 20:41
Yes it is. Inside the frame rail just under your feet, under drivers floor board. Check it at the fuel vent first.
DickWells
02-14-2009, 07:23
You might want to take that new filter out and check a thing or two. There's a plastic spacer/screen or whatever it is in there, (I think it's under the filter, but don't quite remember) If you don't make sure the old one comes out with the old filter, you'll get a jam-up in there that won't seal with the new filter. Not sure of the details, but am sure I was a victim of this problem, once. Also, the filter seal is sort of captive by a thin metal retainer that can come adrift if not handled gently. All this is IIRC, If I Recall Correctly, of course.
Lift off the cover of your electrical power distribution center just outboard of the master cylinder and check for your lift-pump relay. Little square relay, I think it's the left front one? Pull it out and look at the bottom of it. You'll see numbers for the connectors/sockets. Take a paper clip or fine, stiff piece of wire and jumper between sockets 85 and 86. You should hear your lift pump running. This is how I always used to purge my fliter housing. Again, IIRC!
You'll be getting to researching Oil Pressure Switches/LIft Pump Relays/Fuel Filter issues in no time. Just let the experts here on TDP keep correcting all the wrong poop that you got from some old Vermont Fart
Good luck.:)
More additional info....
We hooked the truck up to a code reader...a few codes came up...
#31 MAP input low
#32 EGR system problem
#33 MAP input high
#44 EGR pulse width error
#57 PCM 5 volt shorted
#78 Turbo wastegate solenoid
The turbo and EGR were replaced before I bought the truck, so we cleared the "old" codes out and took the truck for a ride. The #31 code was the only one to come back.
Dick Well.....I welcome all info and help...thanx for your input
a5150nut
John C.....I'm going to check the filter tomorrow when time become available
You need to drain the water from the filter. The filter is designed to separate the water. You do not want to run the water through the system, like you might with a gas engine. Fish the hose coming from the bottom of the drain valve on the thermostat housing out and put it into a jar half full of fuel. Run the engine and open the drain. If fuel or water runs into the jar, your lift pump is good. Continue until enough has come out to ensure no water remains in the filter. If the level in the jar goes down when you open the valve, close it immediately. Your lift pump is not working and needs to be fixed. If you allow air into the system you'll have trouble getting it to run again until the pump is fixed. Once all that's done, it won't hurt to change the filter.
If I have to replace the lift pump, how do I prime fuel through the pump?
I'm not sure I'm looking at the right hose. Am I looking for the hose that goes back under the intake manifold? There is a hose connection on the top of the petcock which I thought was the right one. When I openned the petcock the engine shutoff immediately.
Burning Oil
02-14-2009, 16:09
I think you have two problems
Bad lift pump
Bad PMD
With the engine off jumper the LP relay and open the petcock. If fuel pumps out of the drain hose LP is good if not it could be the OPS or LP is bad. Thats just a rough test you really need a gauge to monitor fuel pressures.
The PMD is harder to figure out unless you have a know good spare.
DickWells
02-14-2009, 18:17
If you have very much (some) fuel in the tank, and the front end's not too high, priming the lift pump will be the least of your worries. I always had to whittle out a plug for the soft line to keep fuel from running all over the place.
DW:)
Ok...one problem may have been fixed. I checked the fuel filter I put in and the gasket wasn't in right, so it was leaking.
I jumped post 85 and 86 and nothing....key on....key off....no fuel comming out of the petcock or the bleed valve on the filter. Is there another way to bleed the filter? I have a lift pump on order.
I'm still not sure I'm working with the right opening on the petcock. I connected a hose to the horizonal connection in the picture below. Is this the right hose.
Burning Oil
02-15-2009, 18:49
Yep, thats the right one. If you are jumping the LP and nothing comes out the lift pump is bad or you are out of fuel in the tank. While you have it jumped get under the truck and grab the LP, see if you can feel it pumping. Also wiggle the wires around and see if the starts it up. Ive had one with bad connections there before.
Once you get your new Lp you may have to crank it awhile even after you purge air from the filter as air has most likey gotten into the IP.
DickWells
02-15-2009, 20:21
I doubt if the wiring changed between 95 and 98, but it's possible. Do you have access to wiring diagrams? It's possible that I'm wrong about the sockets to jump on yours. If 85 and 86 are correct, then you should be able to hear the LP ticking at a pretty rapid frequency, switch on or off.
I've read that the LP's have the reputation of rusting out from water sitting in the bottom of the case. I put a RayCor filter in ahead of my lift pump back on 01. Never did replace a LP, but did have to buy a new OPS, once. That was when I put in a relay to take the electrical load off the OPS (oil pressure switch). There's a thread going on in here somewhere right now on this very issue.
Keep up the good work, and good luck.
Dick Wells:)
The hose running under the manifold is the fuel line from the filter housing to the valve. The hose going down is the drain. Pull it out and put the end into a jar Open the valve and fuel should come out the hoes into the jar. (GET THE PUMP WORKING FIRST!!!)
Once the pump is working and the filter purged of air and water, most of your other issues may go away.
The MAP sensor is on the firewall above the brake booster. It should have a vacuum line "T"d into the line from the EGR solenoid to the EGR valve. It measures the EGR control vacuum.
Like I mentioned, I put the fuel filter in wrong and the gasket was messed up. I also put a new lift pump and MAP sensor in, and the truck is running like it was before I started "fixing" it. It's also still shuttering around the same rpm as posted before and the service engine soon light comes on periotically....so I guess I'm back to square one.
I”MMMMMM back!!!!
OK….the truck is still “shuttering” around 1500-1800 rpm. During one of my trips to the auto parts store I was told that I needed to put an additive in at every refueling due to the low sulfur fuels; I was told that the engine was no made to run on the new fuels. I bought a bottle of diesel kleen, used it for the first tank. On the second tank I didn’t use it, and the truck seemed to run worse. So, my question is, is there any truth to what the part guy told me?
And has anyone heard of an engine flush? Suppose to clean the injectors. Not the stuff in a bottle…the kind they do in an auto shop. Are they worth it? Think maybe that might help my problems?
Burning oil mentioned a PMD. What is a PMD and where is it located? And how will I know if it’s bad?
The additive is to provide lubrication to the injector pump. Two-cycle engine oil works fine, as do some other products. The other questions, I can't answer as I'm blessed with an all-mechanical engine
I'm betting you have a problem with the EGR system. DTC 31,32 and 33 all point to that, Pull the vacuum line off at the EGR valve and stick a golf tee in the end of the line so it doesn't leak vacuum. See if the problem goes away.
The 31, 32, and 33 codes have all been clear. The guy I bought the truck from replaced the EGR. Once I cleared the codes, the only one coming back is 78, the wastegate sensor. Just to be sure I cleared the codes again, drove about 100 miles and checked...same thing, code 78. When I move the actuator on the side of the turbo, I can hear air moving in and out of one of the three sensors on top of the engine. I'm assuming this is the wastegate sensors (see enclosed pic). Should air be moving passed this. The local Chevy dealer has a listing for 2 different sensors..1 with a vent and cover, and 1 w/o a vent. Do you think this would solve my problems? Also, in the second pic of the turbo, should there be a spring on the turbo to return the actuator?
Most likely it is the wastegate solenoid, the front one in the second picture. If you pull the vacuum line off the actuator the arm should move freely. Test the actuator for leaks as well as the vacuum line to the solenoid. Put a vacuum gauge on the line going to the actuator and expect about 15 inches of vacuum at idle. Engine off the solenoid vents the actuator to the atmosphere.
Still have the "stutter"?
Yes, I still have the stutter. Could this be the problem? The actuator moves freely with the vacuum line off, and when I manually pull a vacuum on the line the actuator moves, so I guess that means there's no leaks on that end. The vacuum line to the selenoid has been "replaced" by the previous owner. I guess the hard plastic hose broke and it's been rigged. I'm looking for a replacement, but since the line is two different sizes on either end I'm unable to use a standard rubber hose.
Check the vacuum from the pump. Should be in the 25 inch neighborhood and steady. Also, try the golf tee trick.
K....I'll get back to you in about a two weeks (maybe sooner if I can get onto my laptop). We're going away to visit friends in Mississippi.:)
Ok….I need to resurrect this thread. I replaced the wastegate sensor and all had been well, until two days ago. Not the truck is acting like it was before the sensor problem. So I have two questions.
(1) How can I test the sensor to be sure that is the problem? I don’t what to buy another $50 sensor just find out.
(2) What would cause the sensor to go bad in less than 6 months? Is something “frying” it?
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