Stalling, fishbites, and no start

[blackonblack]

I know there is a lot of information on TDP regarding this but I am near the end of my rope with this issue I am having with my '99 6.5. I'm going to start from the beginning to give the whole background.

I bought my truck Sept 24 '07 and it ran fine for awhile. I had a a CompuStar alarm and remote starter installed Nov 9 '07. My truck started to act up a few weeks later. It would stall and restart right away without having to do anything.

The problem got worse and worse, sometimes stalling and me having to pull over and restart the engine. Most of the time it would restart right away, sometimes it would take a few minutes.

I began to investigate on the internet and that is when I joined TDP. The first thing I came across was the PMD problem. I promptly purchased a new one and a remote mounting kit. The truck ran well for some time after that. I thought the problem was licked.

Jan 29 '08 the truck shut off on my on a longer road trip. It would not restart period. It was towed to a local GM dealer in Nanaimo, BC. No codes were set. They noticed the Fuel Pump Relay was clicking rapidly and had no communication with the ECM. The dealer disconnected the remote start system and still had the same problem. They again diagnosed a communication loss to the ECM. They replaced the ECM ($670 parts and $360 labor). The truck ran great for 2 days and then started the stall problem again.

I took it to a local (Vancouver) GM dealer and asked them to check the fuel system and replace the fuel filter at the same time. They did this but then could not restart my truck. A technician (keen in electrical problems) diagnosed and repaired a "poor connection to the ECM Battery". I'm not exactly sure what they did. The dealship closed since then and I haven't been able to locate the tech.

The truck ran GREAT, literally not a single problem, for months up until a recent trip to northern Vancouver Island. I drove up about 600 km, 60 km of that off road on logging roads. On the way home the trcuk started to stall/restart while driving. Finally it just died and would not restart. After about 15 minutes on the side of the road I was near having it towed and it majically started without explanation.

I managed to limp home and have had the problem ever since.
I have replaced the Lift Pump, changed the fuel filter again, checked all grounds I can find, changed the oil pressure sensor, and fuel pump relay. When I cleaned all of the grounds the truck was in a no-start situation and when I finished cleaning the truck started right up, but this only lasted another 2 days. Same thing with when I replaced the lift pump and oil pressure sensor.

My options (as I see it) are few at this point. I have read that the ignition switch on these trucks go. I could replace this. I have read it is not uncommon to get another bad FSD when replaced. I could change this again. I have also (just recently) read on TDP that a worn advance piston on the DS4 can cause this problem. Or maybe it is related to the remote starter system (which the dealer swears he has been installing for 20 years and never had a problem).

I am hoping that someone can provide some next steps. I am only into this for about $2000 at this point but I would like to stop the bleeding soon.

Regards,

Marty

[Hubert]

The truck ran GREAT, literally not a single problem, for months up until a recent trip to northern Vancouver Island. I drove up about 600 km, 60 km of that off road on logging roads.

Was this off roading pretty warm weather I have no clue what ambient temps are there but if you experienced extended high under hood temps with appreciable low end grunt making some heat it could have caused heat related FSD issue. Not sure just a thought but I guess if people in LA rush hour with AC on are not hot under the hood and killing FSD's a logging road shouldn't do it. Depends on mount and actual temps. Might get more jolts and vibration to add to heat problem on logging road.

What type of FSD mount do you have and where is it? If its intermittent and fixes itself I tend to think electrical bug either intermittent short or open? (probably FSD bug) especially if no codes are set and it runs good otherwise. But no way to tell FSD/PMD.

Check battery cables and grounds clean'em up good again to start with.

[blackonblack]

I have relocated the FSD on an aluminum heatsink on the drivers side fender between the battery and Fuse block.

I could clean the grounds and battery connections again but I really don't think that is it at this point. I tried doing that again during one of my no-start sessions and it didn't resolve the problem.

I think I will replace the ignition switch and see what happens.
If that doesn't work I'm not sure what to do next.

[JohnC]

Is it setting any codes now?

Have you paid close attention to the ground point on the rear passenger's side of the intake manifold? This is where the PCM and engine harness grounds come together. Make sure the conductors are not broken inside the insulation where you cannot see them.

Check the extension harness for the PMD carefully. Where is the ground wire that was originally on the screw on top of the injection pump?

A volt meter should be able to tell you if the ignition switch is the problem.

[blackonblack]

The check engine light has not come on. I'm not sure if that means there are any codes or not.

I have cleaned the ground wire connections on the manifold but I didn't really look for damaged wires.

I will check the PMD ground wire. I don't recall moving it.

I'm not convinced that it is the ignition switch.

As it stands right now, the truck won't start except for a few times that it will start and then stall 5 to 10 seconds later.

[Artworks]

Check the connection on the extension harness to the FSD, My connection had worked it's way loose. I cleaned all terminals with a shot of conntact cleaner,( may even try rubbing the conntacts real gently with emery), and cover with dielectric grease I installed a tie around the FSD to hold the harness end to the FSD. Any moisture will corrode the connections evough to cause problems. Also check the torque of screws holding the FSD to the 'sink'. remove, clean the contact surface and re- install.

[blackonblack]

So the truck wouldn't start yesterday. Sometimes it would, but only for a few seconds. The I went out today to work on it and it started right away and continue to run. I coudn't get it to stall. It was a very warm day today. I started going over each wire, one by one. I found a severed wire that kept my hood light from coming on. That was nice but not the problem.

Then I found that the cable connecting the two (+) terminals was broken and only holding on my a thread. Could this have caused this problem? Maybe one of the batteries was not charging enough or not at all intermitantly.

[Hubert]

Tough to say might have caused some goofy stuff if voltage jumped around.

I think the PMD/FSD will function down to about 9 volts and the truck can operate off of one battery. But if one battery intermittently jumped in or out voltage may fluctuate and caused issue.

Battery voltage issues may shorten life of PMD/FSD never heard anyone say that explicitly but I suspect it might.

Grounds are just as important so check them too. I kinda still suspect FSD as once it goes it can get real sporadic and unpredictable. It might work then not then be fine for weeks to fail badly and no start wait 1 day and start then stall intermittently again.

What kills me with these trucks the voltage can be all screwy and dang if my battery light ever comes. Only time is when I am on run at start up (when all functions come on to check for bulbs ok). Otherwise not sure when battery light comes on.

[blackonblack]

Wow. I replaced the battery cable yesterday and the truck fired right up. I drove it a few places with no problem. Took it to work this morning, again no problems. Went to leave work and the truck will turn over but not start! Ahhhhh!

I have checked every ground (to the manifold on both sides) and to the frame. I have check the ground to the body above the ECM in the glove box. All of the battery terminals are fine.

I never see any voltage problems on the instrument panel but I guess that doesn't mean anything.

The only things I can think of (in order of what I believe the cause may be):
1. Bad battery (I still have to check the voltage and amps for each battery)
2. Bad FSD/PMD (kind of expensive to just change)
3. Bad Inition Switch harness (not really cheap and not the easiest to replace)
4. and I hate to say it, a bad injector pump. (everyone says this is not the problem)

I just don't know where else to look. I've run out of options that I know of. Anyone with any more words of wisdom would be greatly appreciated.

Marty

[More Power]

So the truck wouldn't start yesterday. Sometimes it would, but only for a few seconds. The I went out today to work on it and it started right away and continue to run. I coudn't get it to stall. It was a very warm day today. I started going over each wire, one by one. I found a severed wire that kept my hood light from coming on. That was nice but not the problem.

Then I found that the cable connecting the two (+) terminals was broken and only holding on my a thread. Could this have caused this problem? Maybe one of the batteries was not charging enough or not at all intermitantly.

As a first step, gotta fix any and all obvious electrical issues you've discovered so far, like bad battery connections, stray wires, etc. You'll have to trust that the remote start was disabled correctly, and I'd leave it disabled till all this is well behind you.

Second, since the engine will run OK at times, the mechanical components inside the fuel injection pump are also OK. But there could be an electrical/electronic issue, but there are other items to consider before replacing the DS4.

The PMD/FSD has always been the single-most problematic component in the entire fuel injection system. If you don't have a "known good" spare to swap in to help in troubleshooting, remove the module from the cooler, and loosen then retighten the 4 screws holding the two power transistors to the module. These screws have a way of loosening due to thermal cycles. Then try running the vehicle to see if that helped....

If the stalling/no starts continue, I'd recommend another getting new PMD/FSD - probably the new DTech replacement module you've heard about. All reports are good for the time it's been out. DS4 owners really need to have a known-good spare anyway.

Do this, then let us know what develops... We'll get you through it.

Jim

[blackonblack]

Truck started fine after work today. I ordered the Dipaco Dtech PMD.
A local dealer here (Vancouver) was selling it for $320.00 + 12% taxes.
I bought one online (ebay) new with extension harness for $209.00 + 5% tax. Paid a little for shipping but in the end I probably saved $75.00.

I am going to locate it in the bumper this time. My old PMD was a 34583. I don't think I like the "limp mode" that it has. I would get the 34264 if I were to get the Stanadyne next time.

Thanks Jim. I'll let everyone know how it goes.

[blackonblack]

I put the new DTech PMD in last saturday. Mounted in the bumper this time. Truck has run flaflessly since.

Thanks everyone. I can't believe this is my second PMD replacement in since I have owned it for 10 months.

Marty

[blackonblack]

When I ordered my new PMD it was supposed to come with a new #5 resistor. When it arrived the resistor was missing. Pissed off and too impatient for them to send the missing item I decided to get the one out of the PMD still mounted on the IP. I had read in some forum where someone took a chissle and easly knocked the old PMD off. So I thought I would take a chance and try it. It only took a few moderate whacks with a regular hammer and chisel on the top right of the PMD and 3 of the 4 bolts gave way. The 4th broke with one more tap. Recovered the resistor and away I went.

[More Power]

Are you saying you installed the resistor pack in the DTech module?

Do they use one?

Jim

[arveetek]

I put the new DTech PMD in last saturday. Mounted in the bumper this time. Truck has run flaflessly since.

Thanks everyone. I can't believe this is my second PMD replacement in since I have owned it for 10 months.

Marty

I had the exact same symptoms as you with my FSD. I had installed a new remote-mounted FSD when I bought the truck, and then two years later, it suddenly stalled and would not restart. Let it sit a while and it would start and run for 30 seconds. Installed a new Dtech and all has been fine since.

It was hard to believe that the FSD was failing again, so I was looking elsewhere for the problem. Turned out I should have started there!

Casey

[blackonblack]

I assumed the resistor resistor was required but questioned the assumption after your post. I contacted DTech and they replied that the resistor is required and the one from the old PMD can be used or you can purchase one from them.

I also noted on their website that they claim that GM has announced that the DTech PMD is now the approved PMD replacement to be used by GM and NOT the Stanadyne PMD.

Are you saying you installed the resistor pack in the DTech module?

Do they use one?

Jim