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Starting issues

JohnnyT

New Member
Messages
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Location
Mocksville NC
Problem: Explain your problem in concise language (ie: Cranks but won’t fire). _Starts then quickly dies. If I rev the engine and drive fast it will stay on however if I leave it sitting for a bit and crank it it will studder and turn off unless I pump the gas petal and drive___________________________

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

- Year: 1995______
- Truck model and class (ie: c2500) _2500________
- Automatic or Standard __auto________
- Mileage: (indicate miles or km) ____over 200,000_____
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) ___________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? Turbo______________
- Ambient outside temp: (indicate *C or *F) ___70F_______
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) ___Diesel ultra low sulfer______
- What fuel additives are you using? __Marvel mystery oil_________
- Where are you located? ___NC__________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter ____week ago_____
- Fuel filter __week ago_______
- CDR Valve? __unsure_______
- Coolant – last flushed/replaced at ____long time no replacment_________
- Oil – synthetic/regular, changed at _____regular 4000 miles ago______
- Batteries – state of charge, (matched set) replaced at 14_____________
- Battery cables and grounds (removed, cleaned and tightened): _______done_______
- Glow Plugs - how many miles on them? __I don't know sorry_______ What type? _____________
- Injectors - last changed at _______________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? ____driving along and it stalled_________
- How was the truck running fine before this problem appeared? _________great____
- Has this problem ever happened before? ___no____________________
- Describe any related factors that might be part of the problem. ______Just replaced the PMD and the lift fuel pump________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) ____ And? ________Yes and none show up


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? ____few secs_____
1f] Does your glow plug light come on? ___yes______ For how long? _____short time____
1g] Do you see smoke from the exhaust while cranking? What color? ___BLACK_____

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) ? ______I belive so___
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? ___________yes

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) ___intake manifold with a heat sink________
3b] Condition of Extension harness (if used) Vendor or Homemade? _good new________
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. ___good______
3d] PMD Make: __resister # 9 ___stradyne______
3e] PMD Age: ____new_________

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) __only when starting i does stutter tho or hesitates____
4c] Does pouring cool water over the IP seem to help with restarting? _______never tried__
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? _unsure__________
4g] Does re-starting seem to reset engine, restoring cruise and power? _________
4h] Changes to dash lights or instruments during stalling events? ___________none

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _______
5b] Any bubbles or oil film in coolant overflow tank? _______
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? ___yes_______

6] Performance Issues
6a] Do you have gauges? ____no_______
6b] Maximum boost under load? ____________
6c] Have you added a performance PCM (reflash) or Chip? _no_____________
6d] Have you changed exhaust / downpipe / crossover? _____no___________
6e] Wastegate – mechanical or vacuum? ____6.5 TD silverado 1995 sorry I don't know___most likely vacum_______

7] Temperature-related Issues:
7a] Single or dual thermostats? ____________
7b] Have you replaced them lately? Manufacturer of replacements? _________
7c] Have you pulled and cleaned Radiator and coolers lately? ___no_________
7d] Have you replaced the fan clutch? Manufacturer of replacement? _____no___
7e] (winter) Have you tested your antifreeze? Good to what temp? ______-25____
7f] (winter) Are you using a winter grille cover? ____no_______

List and describe any other factors which are not addressed in this checklist. We can’t see, hear, smell, or touch your truck, so the more descriptive information you can give, the more likely it is that somebody can assist you.

_________________________________This truck has a new PMD and Lift pump I thought it would fix the problem but still not able to start without stalling could it be the check valve in the fuel line? THANK YOU
 
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The manifold is the second worst place to mount the PMD. Best is outside the engine bay (IE: Heath kit w/seven year warranty). Sounds like PMD to me but best to wait till someone else chimes in to be sure. You said you wern't sure if you got steady flow from the t-valve whe running the lift pump. the valve is located next to the water crossover manifold and the line runs down next to the vacum pump and can be pulled up to watch the flow if any. Do a search as I think you year has a jumper to run the lift pump located under the hood. Try that lil free test first before replacing parts.
 
You changed the LP but have you changed the OPS. In 95, the OPS run the LP during engine run after cranking. Try jumping the LP first and see if you can keep it running. If yes, then OPS is bad. Changed it with ACDelco OPS not other brand.
 
How long have you been using Marvel Mystery Oil? Apparantly it does nothing for lubricity according to testing, so you may be killing your IP with ULSD. Try using some TC-W3 2-stroke oil instead.

Also sounds like OPS may be inoperable. You can see if it is working if you get the truck running and its idling check for voltage on contact G of the OBD port. That will show you how much voltage the OPS is sending to the LP. You can even monitor it while driving I guess to make sure its always working. (This is only true on 94-95, and on 93 it is on pin A)

I also would believe your injectors may be leaking since you get so much black smoke at startup. leaking injectors can cause a lot of damage, like scratched cylinder walls. as it dries out the rings and removes all the lubricating oil.

Also, Stanadyne PMDs only rated to 180*, I wouldnt leave it in the engine bay. My D-tech, rated to 257*F seems to be happy enough, as Ive never seen it get over 150*F. For now, at least make sure the black ground on the harness is secure, and it should be connected to the top of the IP where it started. If you have the kind where its on the side of the heatsink, extend it back to the IP or at least run another ground back to the IP.
 
Hmm, black smoke at startup.

Sounds like its starving for air right off the bat...

Are you sure nothing is clogging your intake path? (end cone off aftermarket filter, or anything else?)

Injectors leaking would be white smoke, raw fuel. Black smoke at startup means for sure its struggling hard for air, (unburnt or partially burnt fuel).

Hows the exhaust side, clogged soot trap?
 
Thank you for all the info I do intend to move my PMD or FSD just not sure where to put it. I will try and detirmine if it's the OPSU and I am really hoping it is. The truck is at the shop so I can only tinker with it while there. anyway if air is getting in the fuel then it's doing the right thing by shutting down right? you see if I rev the engine to start it then quickly shift it into drive I can usually get it going but it stutters when accelerating to much. but other than that it has not stalled while driving. so I am guessing that you are right it is the OPSU. I will get back to you all when I have tried all your suggestions. Thanks alot. O and by the way I think the black smoke was my revving the engine to much on start up usually it just has a little white smoke when properly started
 
The LP is good and so is the OPS I belive. tstill won't start if left for 10 minutes I think it has somthing to do with the fuel lines. is there a check valve in the line that stops the fuel from going back into the tank when the engine goes off? in order to start it I jump the LP to prime the fuel flo. even then I have to hit the gas petal and take off in drive to keep it going. it stutters and hesitates like it wants fuel then after a minute or two it evens out and runs well could this mean my injector pump is on the fritz??? my guess is that it is the check valve but I don't even know if a 6.5 has one.
 
To see if your ops is good when you have it idling, check the voltage on pin G of the OBD port. Its the bottom left one. that shows you how many volts the OPS is sending to the LP.
 
will do buddy thank you for the quick reply. so if the ops is not working then the lift pump isn't activated when I start the engine right? so by jumping the LP I am bypassing the ops. even by jumping the LP I still need to pump gas petal to keep it going. does the ops run the LP even after It's done cranking? like right after it turns over?
 
OPS runs it after cranking, when you have oil pressure. Lift pump relay runs it while cranking.

If you can find the lift pump relay, there is a purple/white wire to it that send the signal to start the LP when the IGN is in the START position. You could hook up the glo plug signal to that wire so you get it during glo.
 
could be something in the turbo if it had sat very long:eek::eek:....lol

it will cause a little smoke at startup...
 

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wow did a mouse get in the turbo? so I checked the ops and then replaced it, problem solved! Thank you for all the help this site is great. If I had taken this to an auto mech that only worked on gas engines then it would have been 700$ for parts at the least. OPSU 23$ had to look for the right tool though. I feel sorry for the people with this sensor under the intake manifold.
 
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