Yet another stalling problem

[JeffMD]

Demographics: tell us about your truck and your ambient conditions:

- Year: _1994_____
- Truck model and class (ie: c2500) K2500 Suburban_________
- Automatic or Standard __________4L80E Automatic
- Mileage: (indicate miles or km) _________290k miles
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) ___________IP Remote FSD post 97 cooling upgrades 18:1 comp, gear drive cam, Heath chip, turbomaster, marine injectors, ATA intercooler, air filter, peninsular intake, banks exhaust, EGT and boost gauges.
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? ____F__________
- Ambient outside temp: (indicate *C or *F) __70 F________
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _________About B-80
- What fuel additives are you using? _Diesel Service White bottle__________
- Where are you located? _________TX____

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter ___6mo______
- Fuel filter ___2 wks______
- CDR Valve? __3 mo_______
- Coolant – last flushed/replaced at ___2 mo__________
- Oil – synthetic/regular, changed at __Syn_about 5k ago________
- Batteries – state of charge, (matched set) replaced at __Questionable___________
- Battery cables and grounds (removed, cleaned and tightened): 2 mo ago___
- Glow Plugs - how many miles on them? __65k_______ What type? ______unk_______
- Injectors - last changed at ___227k____________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? ___idling___________
- How was the truck running fine before this problem appeared? _normal____________
- Has this problem ever happened before? __no_____________________
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) __Y__ And? __35 (OBD1)______


Diagnostics:

1] Starting:
1a] Does the engine start? ____Y_____
1b] Does the engine crank over? ____Y____
1c] Are your batteries fully charged? ___unk______
1d] Have you removed, cleaned, and tightened all battery connections? __Y______
1e] Does your Wait to Start light come on for a time? How long? _Y 10 sec__
1f] Does your glow plug light come on? _________ For how long? _________
1g] Do you see smoke from the exhaust while cranking? What color? ________

2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____________
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? _________
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? ___________
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ___________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) _Heat sink in front of passenger battery__________
3b] Condition of Extension harness (if used) Vendor or Homemade? _good____
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _Good________
3d] PMD Make: _Stanadyne via SSD__________
3e] PMD Age: __about 30 months___________

4] Stalling Issues
4a] Do you experience stalling only when hot? __no__________
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) __no____
4c] Does pouring cool water over the IP seem to help with restarting? ___unk______
4d] Is stalling momentary (engine recovers)? _no________
4e] Does SES light come on when engine hiccups? __no_______
4f] Does cruise control quit working when engine hiccups? __unk_________
4g] Does re-starting seem to reset engine, restoring cruise and power? _yes________
4h] Changes to dash lights or instruments during stalling events? ____no_______

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? __no_____
5b] Any bubbles or oil film in coolant overflow tank? _no______
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? ___no_______
5d] Excessive white smoke from exhaust on cold start? __no_______
5e] Excessive black smoke from exhaust under hard acceleration? ___no_______

6] Performance Issues
6a] Do you have gauges? __yes_________
6b] Maximum boost under load? __15psi__________
6c] Have you added a performance PCM (reflash) or Chip? _____yes________
6d] Have you changed exhaust / downpipe / crossover? __Y/Y/N__________
6e] Wastegate – mechanical or vacuum? __Mech____________

7] Temperature-related Issues:
7a] Single or dual thermostats? _Dual___________
7b] Have you replaced them lately? Manufacturer of replacements? ___No______
7c] Have you pulled and cleaned Radiator and coolers lately? __yes________
7d] Have you replaced the fan clutch? Manufacturer of replacement? _Y unk via Heath_______
7e] (winter) Have you tested your antifreeze? Good to what temp? _Y -20F______
7f] (winter) Are you using a winter grille cover? _N__________


I have had an intermittent DTC for the fuel solenoid response time. While cruising when light trips the cruise drops out. After light goes out the cruise will re engage. Light will trip almost constantly on one short trip, then after shut down, sitting for an hour, will restart fine and not come on for a week.
I do not have a box that will show me the response time like a Tech1.

I know my current placement for FSD and heat sink is not optimal, but it does get air flow from the former duct work that fed the snorkle in the fender.

So I am wondering, FSD or the solenoid itself? If it is the solenoid, how much of a pain is that to replace?
And while I am at it I guess I will clean my grounds again......

 

[RadioMan]

Charge up them batteries, let them sit over night, and test each cell with a hydrometer. That will end the questionable part of the batteries...

Next time you get it run let it get up to temp, shut it down, wait 5 minutes and feel the FSD. If it's not cool - Move it... Sure sounds like FSD, but I imagine you know your truck pretty well if you did the mods. Sure reads like a super truck.
Good Luck!

 

[JMJNet]

Can you guarantee air movement when the truck is shut down to the PMD?

That is the cause of most PMD/FSD failure. Heatsoak after the truck is shut.

I did a rough test one time, there is an increase of 10 degrees temperature inside the engine compartment. The heatsink suppose to shed the heat but it will soak the heat and transfer it to the FSD.

If you still don't believe me, read up on the recent thread by TurbineDoc on his PMD experiment.

 

[Tookie]

Can you guarantee air movement when the truck is shut down to the PMD?
That is the cause of most PMD/FSD failure. Heatsoak after the truck is shut.

I have mine in the bumper, I have no air movement when it's shut down

 

[JeffMD]

As far as airflow when the truck is shut down, no I cant guarantee it. However, the passenger side battery is between the heat sink and the engine, so I am not getting direct radiated heat. It is located behind the passenger side headlights where the duct was that diverted the ram air coming through the grill over to the snorkle in the fender. If I had it to do over again I would have bought the longer extension harness and gone either in the bumper or on a frame rail.

 

[Rodd]

A faulty pmd won't allow your cc to work. In addition on some (not all) gm vehicles the cc will not work w/ the ses light on. When it stalls does it throw a code? The fuel response code is an IP code. There are 3 different codes you get for the IP. Opt sensor, fuel metering, and one other that isn't coming to me at the moment. They are basically the 3 electrical plugs that plug into the IP. You didn't post if you checked the tvalve to make sure the lp is working. On your truck both the LP and the oil pressure switch bring the fuel to the IP. If you get fuel from the t valve then the next step is the ops. The ops is only $25 at most parts stores. If those are good then the cheapest way to figure it out would be to mount a known good fsd outside the engine compartment and see if it dies again. If it does then I would replace the IP. If it doesn't you have found your problem.

 

[JeffMD]

Lift pump was good as of two weeks ago, but haven't checked in the last couple of days. One of the things I was wondering is if it is possible that it is the fuel solenoid itself and not the driver. If so how big a deal is that to swap it out? I have factory service manuals but they don't say anything about it. I think GM's solution is to swap out the pump.

Of course this could be used as a convenient excuse to upgrade some stuff, but if I have to replace the IP again it will be a loooooong time before the Mrs lets me get my A-Team Turbo!

ETA: I was also wondering about the OPS as the stalls were so soon after starting. But, that wouldn't explain the code. But, are the two necessarily related?

 

[JMJNet]

I have mine in the bumper, I have no air movement when it's shut down

No but there is no engine compartment shutdown heat either. So the ambient will be less than the heat generated by FSD and completely disspated by heatsink.

The argument that people have is about air movement. Air movement is sufficient but not necessary if there is a way to dissipate heat.

Study TD thread. That was the first thing I read when i joined DP 2 years ago. It is quite interesting and remind me on some basic thermodynamic in college.

 

[JeffMD]

Well I went ahead and replaced the FSD (PMD) with a D-Tech. That seems to have been the issue. I guess I had been running in limp mode for a while because it was a completely different animal when I took it for a spin. No codes, no stalling, and this truck really runs!

So I guess about all thats left is a new lift pump, cross over, feed the beast, and a new turbo!

 

[Dan Hunter]

Darn. I'd really like the next person that remote mounts the FSD inside the engine compartment to remove the hood and drive it as part of an analysis. Seriously, I'm enormously curious.

 

[Turbine Doc]

Lift pump was good as of two weeks ago, but haven't checked in the last couple of days. One of the things I was wondering is if it is possible that it is the fuel solenoid itself and not the driver. If so how big a deal is that to swap it out? I have factory service manuals but they don't say anything about it. I think GM's solution is to swap out the pump.

Of course this could be used as a convenient excuse to upgrade some stuff, but if I have to replace the IP again it will be a loooooong time before the Mrs lets me get my A-Team Turbo!

ETA: I was also wondering about the OPS as the stalls were so soon after starting. But, that wouldn't explain the code. But, are the two necessarily related?

No as a bad lift pump will not shut down a truck, a healthy IP will pull it's own fuel provided the IP is healthy and the tank sock is clean, the fuel filter is clean. will make it run like it's "limped" at power but engine should not shut down as a result of it.