Sticking throttle and lopping

[625fireman]

Problem: Explain your problem in concise language (ie: Cranks but won’t fire). ____Throttle sticks when cold and surges at idle when warm________________________

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

- Year: __1994____
- Truck model and class (ie: c2500) __K3500_______
- Automatic or Standard _nv4500_________
- Mileage: (indicate miles or km) _87000________
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) __PMD, ecm, throttle pedal, coolant sensor_________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? __f____________
- Ambient outside temp: (indicate *C or *F) __typical NE ohio ________
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) ____2_____
- What fuel additives are you using? ___none________
- Where are you located? __NE Ohio___________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _spring 2008________
- Fuel filter __Feb 2009_______
- CDR Valve? ___never______
- Coolant – last flushed/replaced at ___aug 2008__________
- Oil – synthetic/regular, changed at ___Rotella faeb 2009________
- Batteries – state of charge, (matched set) replaced at __set Aug 2007___________
- Battery cables and grounds (removed, cleaned and tightened): ______yep________
- Glow Plugs - how many miles on them? __original_______ What type? _____________
- Injectors - last changed at ___orignial____________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? ___driving___________
- How was the truck running fine before this problem appeared? ________normal_____
- Has this problem ever happened before? ____constant since nov 2008___________________
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) _y___ And? ___none_____


Diagnostics:

1] Starting:
1a] Does the engine start? ____yes_____
1b] Does the engine crank over? ___yes_____
1c] Are your batteries fully charged? ___yes______
1d] Have you removed, cleaned, and tightened all battery connections? ____yes____
1e] Does your Wait to Start light come on for a time? How long? ___yes 10 sec avg______
1f] Does your glow plug light come on? __saa _______ For how long? _________
1g] Do you see smoke from the exhaust while cranking? What color? ___no_____

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

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) ____intake_______
3b] Condition of Extension harness (if used) Vendor or Homemade? _________
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _____good____
3d] PMD Make: __stanadyne_________
3e] PMD Age: __new___________

4] Stalling Issues
4a] Do you experience stalling only when hot? ___n/a_________
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ___n/a___
4c] Does pouring cool water over the IP seem to help with restarting? _____n/a____n/a
4d] Is stalling momentary (engine recovers)? __yes_______
4e] Does SES light come on when engine hiccups? _no________
4f] Does cruise control quit working when engine hiccups? ___n/a________
4g] Does re-starting seem to reset engine, restoring cruise and power? ____no_____
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? __yes_______
5e] Excessive black smoke from exhaust under hard acceleration? ___no_______

6] Performance Issues
6a] Do you have gauges? ___yes________
6b] Maximum boost under load? ____15________
6c] Have you added a performance PCM (reflash) or Chip? ______no________
6d] Have you changed exhaust / downpipe / crossover? __yes 3" straight______________
6e] Wastegate – mechanical or vacuum? ___mech___________

7] Temperature-related Issues:
7a] Single or dual thermostats? __single__________
7b] Have you replaced them lately? Manufacturer of replacements? ____aug 2007_____
7c] Have you pulled and cleaned Radiator and coolers lately? ___aug 2007_________
7d] Have you replaced the fan clutch? Manufacturer of replacement? ___no_____
7e] (winter) Have you tested your antifreeze? Good to what temp? ____-35______
7f] (winter) Are you using a winter grille cover? ____no_______

I have tried a bunch if things to try and stop the loping. It only does this when after the engine reaches 100* or so degrees.
1. I changed the coolant sensor on the crossover- no change.
2.swapped the throttle pedal- no change.
3.swapped the ecm- no change.
4. new pmd -no change
5. grouned heat sink to IP- no change
6. cleaned all grounds- no change
7. pulled hair out- no change

If I lugg the engine down at idle(just momentarily to stop the loping) it will quit loping for about 5 mins but it wil eventualy start doing it again.
The newest thing is when cold the throttle will stick if I rev over 2,000 before I shift.
I am thinking my IP is going out what do you think???? Am I on the right road or do I head in another direction??
TIA Joe

 

[buddy]

When you changed to the 5spd did you get an ECM from another truck?

What part number is the PCM you have now, and what is the 4 letter broadcast code on the chip inside of the PCM?

Do you have a 5068 model IP on the truck? Or what model is it?

This would normally be the PMD or a bad IP. If you have a Stanadyne PMD you should get it off of the intake and out of the engine bay, as those PMDs are only rated to 180*F and the engine can run 210*F, but I havent had any issues with the D-tech type rated to 257*F.

I'll run through my factory manual and see if I find any useful tests you can do.....

You should be using some additives if running ULSD fuel, as with no lubrication will kill the IP. Throw in some TC-W3 2-stroke oil and see if it helps, like half a quart for 34 gallons.

 

[Turbine Doc]

Try to run with cruise control as that takes the APP out of the loop, no such thing as "sticking throttle" on these as it is a"fly by wire" electronic speed control, if your engine is running away and sticking at 2000 rpm then most likely culprit is broken armature shaft in the IP's fuel solenoid armature, which means a new IP. Call Bill Heath www.heathdiesel.com he has a handy diagnostic tip involving warm up & revving at different rpms to help diagnose this, I don't recall the tip in full, I'll get with him later today as well, may be on his blog also, been a while since I had to look for it.

 

[625fireman]

BUDDY no I did not change the ecm with one from a manual trans. I swapped it with the other truck in my sig. They are sister trucks( both originaly ordered by the same city). For the first year after I swaped the trans I had no issues with this is started after I had a bad load of fuel (water) SORRY I didn't mention this before. The lopping at idle is something I was living with but now with the throttle sticking when cold I have to do something. As for the pump model I dont know still have to look at the tag. I know I need to get the fsd out of the engine bay just haven't had time to. but swapping it out with a new one didn't change anything. I ahve the three red and white service manuals but I tried everthing I found in them, but maybe I missed something.

TD I dont have cruise so I cannot try this. Calling Heath is my next step if no can come up with different ideas than what I tied already.

 

[buddy]

How long have you been running it on #2 fuel without additives? And then water in the fuel, sounds like you may have a damaged IP.

It would be good to know the IP models, of each and then the PCM part numbers youre using. In 94, depending on the build date, a K3500 could have the 5068 pump which used different signals from the PCM. And even if one of them came with a 5068 pump if it had been replaced in the last many years a technician may have replaced one of them and the ECM EPROM to the 5067/5521 compatable IP type. The build date is on the drivers door on the top right of the sticker.

The IP model can be found on the side facing the intake, so using an inspection mirror or any little mirror and a light you can read it off of the tag. The PCM part number can be seen by removing the glove box liner. There will be a service/part # and then another number which contains the EPROM code that came with it. But you should see what EPROM code it actually has in it, by pulling the PCM out (which you can do with the wire harnesses still plugged in) and opening the flap on the back and seeing what code the chip/EPROM has on it.

 

[buddy]

Hey fireman, did you find a solution to the issue, or those part numbers?

 

[625fireman]

No not yet had the flu over the weekend. Didn't get anything done. This bug was reall asswhopper. Put my boy in the hospital for 2 days, then me and the wife on the couch for 4 days. Hopefully today or tomarrow.

 

[Turbine Doc]

Sorry to hear that fireman, hope you all get well soon, it ran through the house here but it did not take us as far down as it got you guys.

 

[625fireman]

Thanks TD Things are better today.
As for the part no. Here is what I found. On the IP: It is kinda hard to read it has been punched over top the oringinal so appeartly its been "rebuilt"
C6 DS4831
5088 (probably 5068) Originally looked like it was 52_7 can't read the third no. very well

As for the comp here is the stick on the outside

serv No. 16183977 BMRM

86BMRMM241400188

16209955 BMRM

86BMRMM241400188

then the chip(it is blue)

4144
BMRM
0073

Joe

 

[buddy]

Thanks, if it was 5068 youd have a real issue with the EPROM not being right, but more than likely you have a 5067 or 5288 IP and it should be fine. Youll want to verify if you can.

If you find that you do have a 5068 then your EPROM is wrong, that BMRM.

So the problem truck still has its Auto tranny? Edit, saw it has NV4500. That is an Auto tranny EPROM and youd have a bunch of ghost codes probably if you did that swap. Does that use the same Vehicle Speed Sensor and buffer module?

I just wanted to verify you had matching IP to EPROM before pressing, will ponder more.

Throw some 2-stroke oil in the fuel, about half a quart to the tank, and make sure PMD is grounded to top of IP.

 

[gmctd]

First, this could be caused by really old fuel, or contaminated fuel, or plugged up fuel filter, or dead lift pump, which can make running noises but pump no fuel as pressure increases from 0 - or failed IP (could be all rusty inside from watery fuel)

- definitely need to verify 5068 or 5288 IP - Prom is drastically different - no such DS4 as 5088

- good IP could be on ragged edge of timing, or\and TSM is sticking or jammed or failed - PCM controls cold-advance and load advance via Timing Stepper Motor

- ESO solenoid should be exactly vertical to plane across valve covers to be within spec - hi-mileage engine should get new timing chain-set so crank\cam timing will be correct for IP timing at that point

- look down on turbo-side of IP at the TSM, should be slightly ratcheting up and down at idle - make sure actuator is not jammed by the fuel-return pipe or wiring harness - if it's free to move, but never moves at crank or run, the TPS motor is jammed\frozen

- running at cold but not warm sez IP outta time, or TPS jammed, or both - with good IP matched to prom and good fuel

 

[625fireman]

Thnaks for replies finally gat a chance to talk to Bill Heath late yesterday. He gave me a few things to check out. I did them and the IP is shot. So now comes some big bucks. Thanks for everyones help.