Humm its time to work on her again

[scoobysmak]

Well I guess since I lasted visited the site it has changed a bit. Before when I had a problem there was a "sticky" that had trouble shooting steps in it, now I do not see it anymore. Did I miss something?

Well I quit driving my truck about a year ago when I kept stalling every where I went. I tried to just go out and start it every month but even then sometimes it would start and other times it wouldn't. Before I quit driving it I put a FSD cooler and a lift pump harness on it (I can push a button to make sure my lift pump is working making it easy to replace a filter, plus it has an LED for a visual check). Besides these two modifications the truck is pretty much stock.

This past week I started to tinker and here is what I found. I had a couple of side post terminals that the bolts were worn to a nub (some jerk used vice-grips instead of using the proper end wrench). I went to replace the ends and found two of the cables severely corroded (The ground on the passenger side battery and the positive cable running from battery to battery, this had a section of about an inch and half bad on the driver side). I cut out the bad sections of the cable(s) and hooked everything back up to fresh batteries. The truck started right up, plenty of white smoke for a minute but think I have a few glow plugs that need replacement.

I drove the truck around the neighborhood came home and then ran a few errands. The truck started fine and ran with no problems (about 20 miles total with at least 8 start-ups, now I think to my self I should have replaced the cables a year ago). The next day it’s raining and cold but I had the block heater plugged in and again started right up and I went to work (6 miles). It rained all day and now I am get in it to go home, It started right up and I drove to the security gate and waited for it to open and as soon as the gate was far enough for me to get through the truck died (I had not hit the gas pedal yet but was fixing too). I was able to start it back up and drove out the gate thinking it was a minor glitch in the matrix, nope I got about 30 feet and it happened again.

I must have started it about 15-20 times and it started right up but sometimes it would run for 2 minutes and other times it died within 5 seconds of starting. Before it would just never start back up so in a way this was a plus. I called my buddy to come get me, so for the moment it’s stuck at work (maybe my boss will think I am dedicated and give me overtime, ha-ha).

My next attempt may be to replace the cables completely; I think I remember something about a ground on the passenger side that makes a world of difference. This is where that "sticky" would have come in handy. What should I look at next? I really doubt it’s the lift pump, my LED is on and I went ahead and cracked the filter and pressed the button on the harness and I get fuel and hear the pump working. I think if the FSD module was bad I would have had warm start/running problems Vs the cold running issues I have now. I have never seen any fuel leaks, I believe if the fuel was bad it wouldn't start at all.

If there is any check that I should do and post back, or if someone can locate the "sticky" I am looking for it would really help.

Just in case my signature doesn't show I have
1994 Crew Cab Dually 2WD, auto

[GMC Hauler]

If you have any bad cables, replace them before waiting for a problem.

The ground you speak of is on the passenger side intake manifold bolt.

I would replace any bad cables, clean the grounds on the intake manifolds, use a ohmmeter appropriately to check for any bad grounds, and fix as necessary. After that, see if you have any problems.

[scoobysmak]

In the search for more answers, I see that a new PMD/FSD module is now made. I did not find anyone that had tried it yet and wonder how well it was working (just thinking one day when mine dies, cause its going to happen). The other concern with this is it looks as if you have to change the wiring harness, is this right? Seems a bit odd, after 15 years I have to change my wiring harness cause the part was faulty from the get-go. Humm..I highjacked my own thread, tomorrow I will try new cables.

The only thick cables I saw were from:
the top of the intake/Alt bracket to the drivers-side ground terminal
the positive drivers-side terminal to the passengers-side top positive terminal
the passengers-side side terminal to the starter
last the negative passengers-side terminal to the front passenger-side exhaust bolt.

The other wires that looked important are from the ALT to the positive drivers-side terminal and from the body right connected 6 inches from the passengers-side negative terminal. If I missed one please let me know.

Also in my search how many grounds are critical? From what I have read the rear intake bolt on the passengers-side to the firewall is critical. I thought I saw once there is a ground to the IP pump that is critical. At this moment I feel like creating a spider web under the hood so there is no question.

My next problem may lie with the IP pump wiring (I doubt this but figure I would put it out there in case there are a few test I could run), I found they used a zip tie to connect the wiring harness to the plug, I guess the clip on the plug broke that keeps it connected (guess being right on top of the engine makes it subject to a few vibrations). Some of the wires that run under the intake also look like they could be in a bit better condition. Is there a test like remove the connector and check for power to see if that could be a problem? Is this part of the wiring harness expensive or hard to repair (hope that it goes to another connector and I can just buy the right harness, but probably not my luck. I have yet to remove the intake so I don't know what I am in for)? If anyone suggest to remove the intake, to make it easy for me, if you know the parts I need to put it back it would be appreciated (aka things like intake gasket, or some other little thing I might forget).

The only other thing I can think that may cause my problem would be some fuel cut-off solenoid. I don't know much about it besides someone lost a socket and an extension and darn near put a hold in the hood. :eek:

One of these days I might get it back running and be reliable, I actually like driving the truck and may do a few mods to it but figure need it to run right first before it strands me again.

[GMC Hauler]

Some of the bolts on the intake manifold protrude into the water jacket, therefore are sealed with sealant. I have found those bolts to have poor conductivity to ground. You have to check, preferably with an ohmmeter.

The wires on the intake manifold are not large. They also connect to the firewall just behind the engine IIRC.

Use an ohmmeter to check all grounds to the battery negative:

Engine to battery negative
Body to engine negative

First check the resistance of your leads. Short the leads together, and remember that value, as you will subtract it from all future readings.

Check grounds as discussed above. Everything should be less than 1 ohm, really less than .5 ohms corrected. Any above 1 ohm, clean and retest.

I added several ground cables myself, and eliminated all problems.

battery to body (each battery)
battery to engine (the the passenger side one)
body to frame (back at the rear shock)

I used battery cables from Autozone to make the extra grounds. They have cables that are suitable for this.

[arveetek]

I think this is the sticky you're looking for:

Stalls while driving. (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=2938)

It's now located in the 6.2/6.5 tech forum, two clicks down from this one.

Casey

[scoobysmak]

Okay now charlotte's web has be installed under the hood. I have 10 AWG from each battery to a body ground (they seemed to use these screws and figure it wouldn't hurt me to either). I have 1 AWG from both batteries to somewhere on the engine (passenger-side to the front bolt of the exhaust manifold and the driver-side to the bracket behind the ALT, both locations that I believe were stock). From the same bolt behind the ALT I have two 4 AWG wires to the intake, one of which is connected to the the passagner-side rear bolt next to the transmission dip stick tube with all the other grounds. I have one more 10 AWG wire from my driver-side ground to my home-made FSD cooler mount just to make sure it has a ground (I believe my harness carries a ground but better safe than sorry).

I did the Ohm test, I got about .3 Ohms for most of the test, sometimes I had to kinda jab my test lead into the engine to get past the grime on it.

I get in with my fingers crossed and uh.......I believe the only change was my interior lights seemed to be a bit brighter (may have been cause it was getting dark). After about 25 cranks I only got it to fire twice, both runs for under 15 sec each. In the process I did find I have one glow plug wire that was not connected. At this minute all I want is eight sticks of TNT.

Now I will go back and read some more, including the link posted, thanks by the way but have not looked to see if its what I am looking for. In all my days of troubleshooting cars, I feel this problem is like stump the master, but knowing me it is probably something so simple a monkey could do it (has anyone felt like all they wanted to do was SCREAM????)

Signed
Frustrated

[JohnC]

Go through the stalling thread posted above.

When you're done, my money is on the PMD...

[scoobysmak]

Ordered one of the new PMD/FSD modules, should get here by the end of the week. "Shotgun effect" taking over, got to try something but not counting on it. What problems should I look for with the new PMD, the one I ordered is made by Flight Systems according to the website. Crossing fingers on this one.

[JohnC]

Maybe I missed it, but, have you checked for codes? Do you have a scanner? Can you monitor solenoid closure time?

[scoobysmak]

I do not have a scanner, I have not checked the codes recently but last time I checked I don't remember anything showing up. I installed the new PMD/FSD, It ran great for two weeks pretty much until today.

Before this I drove it about 15 miles total with no problems. Today I hop in and it starts right up, I let it idle for about 15 min and let it warm up. I took it around the block a few times and was heading home and poof, the truck just died (I was on a pretty step hill so I let off the gas when this happened).

I coast into the driveway and attempt to start, it just turned over. I popped the hood and took a look, nothing unusual here. After about 5 min of scratching my head and attempting to start it 2 or 3 more times I unplugged the new FSD and plugged it back in. I hopped in the truck and it started. I now race up the driveway and as soon as I let off the gas it died. I attempted to start it again, the first time it did not fire up, the second time it did but I hit the gas and after I left off it died again. I started it once more but it died about 2 seconds after it was running.

After this I just left the truck in the driveway and went inside (its raining). Now I wonder in my mind does heat, rain, or could it be a fueling issue when I let off the gas have anything to do with my problems. I am now researching where to buy 8 sticks of TNT.

[JohnC]

Lift pump? Fuel filter?

[scoobysmak]

I can prime the fuel filter with my lift pump harness, the LED is on, fuel comes out the top when I loosen the cap. I hear woody woodpecker going to town when I turn the key to ON. Fuel filter has maybe 50 miles on it and looks clean (yes I know what looks clean may not be clean but figure 50 miles to clog, I would see something on it). Doubt these but sometimes its the small things that kick you in the butt. If there is something more specific you want me to try let me know.

[scoobysmak]

Just to go see, I went and did my OBD1 code checks, I got code 12 which of course is no codes thrown. Got fuel to the magic "T" so then I cracked the fuel filter and got fuel. My next attempt might be to crack an injector line. Do I need to do all of them or just a few? If I do get fuel here I assume my injector pump went bad or would it be something else? Any other suggestions?

I found a special on TNT will 3 sticks fit per cylinder (1 case of 24 cheap, just kidding)

[scoobysmak]

Well to update my update, I just went to see if I checked the codes correctly wasn't sure if I waited for the three cycles before I made my code 12 call. I did wait long enough, this time I let it cycle 3 times on code 12 (basically got 9 code 12's in a row). The last time I was outside I tried to start it and it wouldn't start (yes I did have the key off and pulled my paper clip before I tried to start it).

This time just to see, I pulled the plug on the FSD module and plugged it back in (I pull the plug where the stock PMD used to be, not at my FSD, I have a 6ft harness now). This time it started right up, I moved it in my driveway so I would not block myself in, I let it idle for about 10 min while I reved it up a few times to see if I could recreate my gas pedal incident without having to brave the streets. It didn't die, I just wish this thing would run or quit (making it really hard to troubleshoot when it runs and when it dies its usually at a bad time).:rolleyes:

[scoobysmak]

Went to the local sears to get new valve stems put in (the old ones cracked and were leaking, makes it hard to be motivated to work on it if every time I have to pump up the tires first). I played around with the the FSD harness before I left. In the driveway it died twice before I left. I did my unplug/plug the FSD back in and it would start every time. I turned the lights on and made it all the way to sears (only about 3 miles away so not like a big deal). I hung around knowing if it stalled they couldn't start it.

While it took them it seems 15 min to put it on a lift (probably more like 5 or less but if the mech tried every lift in the shop before he finally went to the big rack they had all the way at the end). It stalled 3 times before he got it on the rack, I was hopeful having the headlights on helped it keep running but so much for that idea. It still died anyway, the first time I did the unplug/replug trick it worked just fine. The next time it stalled I had to unplug it twice before it would fire and it only stay running for about 3 seconds. The third time I just pushed the wires in the plug a bit harder. This time it stayed running long enough to move it the foot he had left to get it on the rack so he could raise it (still took him about a min but he cut it off after this time).

After waiting about 45 min they were done and he started it and pulled it off the rack fine and turned it off. About 5 min after that I was paid in full, started it up and drove it home with no problems. I am not sure if it acted up cause I got it warm or it hates my guts.

Before I left for sears I moved this harness around and only twice did it seem like it was going to die for a split second but then kept running, I kept wiggling the harness but it never died on me until I closed the hood. The only other thing I think is a bit off is when ever I shut the key off the engine stops that split second. I remember it turning over once or twice after I turn the key but maybe I just been driving other vehicles too long.

PS. update on the TNT, the Department of Homeland security got involved, for some reason I doubt I can get my hands on any, looking for suggestions??