6.5 throttle problem

[gomer]

Hello I am new to this site. I have searched around but am still having issues. I have a 95 6.5 5spd. I just bought it I relocated PMD has a new OPS. I am having trouble with it starting it is getting air I have to bleed the water separator after it sits for a day or so. I have jumped the relay for the fuel pump and it makes the normal sounds and then sounds like it is skipping a beat. I have a new one I am about to put on to see if that helps the starting process.

I pulled the codes with a paper clip and it is showing 22 52 53 63. I had the alternator checked and the batteries and all check good. I read somewhere that some of the codes could be due to a regulator in the alternator but it checked good.

I am also have problems with the throttle being very touchy so yesterday I pulled the pedal and position sensor off and drilled a small hole in it and sprayed electrical cleaner in it. The throttle is much better but still has issues at very slow speeds. I have looked up the parts but are a little out of the price range right now.

I guess my main concern is to get the codes figured out I have heard electrical problems create havoc on truck like these. Any help will be greatly appreciated.

[racer55]

Start with cleaning and securing the 3 grounds at the rear of the intake on the passenger side of the engine.
If that does not help test the peddle sensors:
http://www.dieselplace.com/forum/showthread.php?t=369589

Then a used assembly from the auto wreckers might be the most cost effective way to repair.

Offsite link for information purposes only.

[gomer]

I changed out the fuel lift pump with a new one I get plenty of fuel out of the filter housing. But if it sits overnight it has a little air in it. I bleed the air out at the filter and then it starts fine. Any idea where the air might be coming from there are no leaks on the ground or anywhere I can see as of now. Can I possible pressure up the tank with an air hose and see if I can get it to leak? I feel the air is getting in between the Lift pump and the filter since the lift pump only pumps a second or so before it is bled. Once it is bled out it will start as long as it is started every hour or so. So going to town can cause problems if you stop for very long
I checked and cleaned the ground on the pass rear head and both battery grounds and pass side frame by down pipe. After this I pulled the codes and all I got was a 12. I took it for test drive it seemed fine at first. Then it started lunging and bucking I was on the pavement and it was chirping the tires and carrying on real pain in the rear. After it did that I did get a dead pedal a few time and sporadic. When I got back to the house I would put it in 1st and let out on the clutch and the rpms would jump from 700 to 1200 or so for a second. I feel if I would have not pushed the clutch in it kept bucking like it did on the road. After I pulled back up I pulled the codes and I am now getting a 35 36.
I went to the wrecking yard last weekend and found 2 pedals one was out of a 95 burb and the other was out of a 95 truck just like mine. I have tried all the pedals and the one out of the other truck seems to be a little better but still not great.
Other things its doing but I have no idea if they are related is the Low coolant level light is on and it smokes like crazy at about ¾ throttle cruising down the road or getting on it. It smokes worse than my 98 12 valve that is turned up.
Any other suggestions? The motor was supposed to have been rebuilt by PO but yall know how that goes. Do yall think the optic sensor filter or the sensor its self could be causing problems? I have read they do some crazy things to these trucks.
Are there other grounds that I can check? The PMD that is relocated on it is one that the PO said was new but I am starting to think they were full of pooh since it was relocated but not plugged in!

[racer55]

Sounds like flight systems PMD failure symptoms but could also be a failing IP.

Air in the filter is a leak in the fuel heater O-ring or the water in fuel sensor O-ring most likely but could also be from the filter O-ring-filters are 1 time use only-if you remove it for any reason it must be replaced.

A plugged filler cap could also be a factor for the fuel leak if there is vacuum in the tank?

You have fuel while cranking I take it,but have you checked LP operation when the engine is running?
OPS powers the LP at that time and it is common for them to burn out-more so if not AC Delco.

[gomer]

I will check the orings might even put a new filter in since I don't know the history of it. What is the best way to check the operation of the LP while the truck is running? For some reason someone has taken the thandle off the engine. Is there a shrader valve somewhere I can tie in to? Thanks again for the help!

[racer55]

You could use the bleeder valve on the filter for testing LP performance while running or Tee a pressure gauge in between the filter and IP.

[gomer]

Well I changed the fuel filter and it looked bad looked like it had motor oil in the bottom of the filter housing. And replace the orings on the sensor and fuel heater. While I was at it I decided to see if it had the optic filter thing and it did not. I went ahead and cleaned the optic sensor too. I put everthing back together and when I got ready to start it I beld the air out by using the lift pump. I jumped it at the relay. As I was bleeding the air I decided to take the fuel cap off and it had a pretty good vaccum. I got air out. I started the truck and it started right up. After a few minutes it started ideling rough. Now when I rev it to 2000 and try to back it off slow it just falls off to 700 and idles rough again. I killed it and checke the code and only code it has now is 36! I guess it could still have air in it but I figured it would not start with air in it. All the electrical connections I unplugged I plugged back in but they all had a broken keeper or snap on them. I have looked back through them and made sure they are plugged in could it be possible I have a bad connection somewhere? The only light on is the low coolant level light. Any suggestions where to go now.

[racer55]

Sounds like time for a new IP.

You could try a new PMD first since it won't be wasted money-everyone should carry a spare.

[gomer]

Thanks thats kinda what I am thinking but I guess I just dont want to admit it. haha I think I will try a new PMD first and see what happen. Thanks for the help if you can think of anything else let me know. Thank you

[DmaxMaverick]

You may want to address your fuel quality issue before anything else. No matter what else you do, it has to be addressed. The dark sludge in the bottom of your filter housing is likely biological (algae). It will only get worse until you get rid of it. You'll need to flush the tank, replace with fresh fuel, and treat it with a biocide for a few tankfuls. If it's minor, treating the existing fuel may be all that's necessary, but you'll go through a lot of filters. If you plan on being on the road a lot, and don't have the time or convenience for frequent filter changes, it's much quicker to flush the tank. Bio-contaminated fuel will cause all sorts of issues, including a pump that doesn't act nice.

[gomer]

Well I finally got around to getting a good pmd and tried it and still no start. I guess the IP finally bit the dust. My dad used to run 6.5’s and he found all the old PMD he kept for spares so I tried them too.
I was given a parts motor that had a DB2 4911 mechanical pump on it. So you guessed it I swapped it out. I put the pump and lines on last night and everything went on well. But now I am having trouble bleeding the lines. For some reason I cannot get fuel to the injectors. I hooked the pink wire up to the fuel shutoff and when you turn the key on you can hear/feel the plunger moving. I only hooked up one wire to the injection pump since its is grounded to through the housing. I did not hook up any other wires to the pump I am not worried about the cold start stuff right now since I am in Texas.
On bleeding the lines I have hotwired the LP so that I know its pumping fuel also by loosening the filter water separator and fuel is coming out. I took the return line off the pump to see if it has any fuel returning to the tank and nothing is coming out of there. I tried bleeding the 4 lines on the driver side since they are easy to get too. I then closed all but one to get the one bled still no luck.
I have read the Bobbie Martian book a few times on swaps like this. It seems that the book is more geared towards the automatics. I have a NV4500 in mine and other places I have read say that its as simple as pump, lines, pedal, and cable. Is there anything yall can noticed I missed right off the bat? Any help would be great! Thanks

[DmaxMaverick]

Are you getting fuel TO the IP? Disconnect the inlet line at the IP, and run the lift pump. This will bleed the line to the pump, ensuring a supply of fuel to the pump, making IP and injector bleeding much easier. Even with everything correct and working, you won't get any significant fuel return unless the engine/IP is turning, either by running or cranking. It can take a lot of cranking to clear an airlock, but usually not too bad. The glow plugs should be removed during this process, to increase cranking speed, and reduce starter/battery load.

Also check the fuel inlet filter at the IP to be sure it isn't blocked.

If you have fuel flow to the pump (at any pressure), and still no fuel through the pump, the ESS isn't opening, or the IP is bad.

[gomer]

Well I took the intake off again and checked to see if I was getting fuel to the IP and I am. Fuel is coming out of the return line now. The check valve on the return side was stuck. I pulled the glow plugs on the drives side. I have a little fuel on the driver side but nothing to be excited about. I have 5 injector lines cracked and only have a seep from a few of them. That is after about 35 mins collective of bleeding. Where is the ESS located I have looked for information on this but cannot find anything. Thanks

[DmaxMaverick]

The ESS (Engine Stop Solenoid) is located at the front of the pump, up top. Should be the pink wire. Disconnecting it prevents the pump from pushing air through it and the injectors while bleeding the upstream supply.

[gomer]

Ok I see take the power away from the shut off solenoid and with the lift pump pumping fuel it will fill the IP with fuel and air will come out of the return line. Is that right? I won’t have a chance to try that until next weekend I am headed back to work first thing in the morning. Thanks again for the help I will let you know if that helps. One more thing do I need all the injector lines cracked or will the 5 I have cracked open work? Thanks

[DmaxMaverick]

Uh, no. Removing power from the solenoid only prevents air from pumping IN, and pushing it TO the injectors. This allows the lift pump to push fuel to the IP, without displacing the existing fuel in pump, injector lines and injectors with air. Without a fresh supply of fuel (or air), it won't be able to pop the injectors. It won't fill the IP until the inlet line is reconnected, and powered. The object is to supply ONLY fuel, no air, to the pump. It takes a LONG time to move air through the pump and system, compared to mostly fuel.

When I change filters, I remove power from the pump, replace the filter, bleed to the pump inlet, reconnect the line and power, and it'll almost always fire up and run like the system was never opened. It saves a lot of time, batteries, and starters, despite the time used to disconnect/reconnect things. I've been meaning to install a Tee at the pump inlet (at the pump), with a valve and discharge line, for the purpose of expediting the process. I never got around to it, over 20 years. It's just never been THAT big of a deal, and cleanup is easy.

[gomer]

Thanks again for all the help. I think it is a never ending battle with this truck. The first db2 IP I put on there that I could not get to bleed ended up being bad. I had it tested at a local injection service and he said it failed the first two tests he performed so he stopped testing and said that’s why I could not get it to bleed the lines.

So then I got on trusty craigslist and found a 93 single cab with a 6.5 and 5 speed 4x4 with a locked up motor and he had sold the turbo off it. I bought it and put the pump on my truck. It was a difference between night and day on bleeding the injectors. It tried to crank as soon as most of the air was out so I put the intake and all the pieces on it and it started up fine had a little air in it but it cleared up. I finished the DB2 conversion and started driving it.

It drove around the house and up and down the street great no problems but as soon as I killed it at the tire store it would not start again. I turned over great but would not fire off. I walked home and then hauled it home to work on it again. It was still getting fuel but would just not start. I started with the batteries and had them tested they tested fine. So then I took the started off know that I read somewhere it has to be turning fast enough to start these 6.5 just like a 6.2. I took it off and had it tested and they said it tested fine. But you know the test they do puts no load on the starter so it won’t show if the starter is dragging. When I got home I took the started off the parts truck and hooked them both up to a battery and turned them over. You could sure tell a difference in the rpms it was turning just by the sound. So I put the one off the parts truck on there and it started right up.

Sorry for such a long explanation but I wanted to let you know all I had done before moving on to my next problem. After it was starting again well multiple times in the driveway. I decided to drive it about 15 miles and killed it and it sputtered and then started up. So I drove it home and when I got home I killed it and it won’t start. I jumped the LP relay to make sure the LP sill works and it was still pumping fuel. I messed with it for just a little while before it was too dark and now it just sits. The next thing I am going to try is to bypass the OPS and see if the fairly new one has gone bad. Any other suggestions would be greatly appreciated