Engine/Transmission (1994 - 1998) No RPM (rev's) after accident repair

[SFPADGETT]

1995 2500, 2wd with service body, auto. Had front end accident (headlights,fenders, radiator, bumper, etc. ; no frame damage) was running great before accident, but not after body shop repairs: Rev's fine in park and netural, but not in D,R,2 or 1 (can mash pedal to floor in D,R,2 and 1 no increase in RPM's); have changed fuel filter, cleaned fuel screen, no fuel leaks visble. Idle in Park /Netural is about 1100, when in D,R,2,1 it is about 800. Fuel solenoid pulls all of the way up and stays up when running, 28-30 PSI from lift pump

 

[Skydiver]

Had the same thing happen to a friend of mines 98 12 valve. Minor wreck, all smoke no power. You have a turbo boost (boot) knocked off.

 

[SFPADGETT]

Thanks for the suggestion, however we have checked the boost hoses and found nothing wrong. Also--NO smoke at all. It acts like it is not getting fuel when in D,R,2,or 1.

 

[LandShark]

Your 95 has a rather simple throttle system - not computer controlled in any way. It's just a mechanical linkage from foot to injection pump. Have someone watch the top of the pump when you push on the pedal and see whats going on, then do it again with the transmission in gear.

 

[fest3er]

Thanks for the suggestion, however we have checked the boost hoses and found nothing wrong. Also--NO smoke at all. It acts like it is not getting fuel when in D,R,2,or 1.

A diesel needs fuel, air and compression to operate. I'd hazard to say it's not getting fuel. Check the boost line from the manifold to the AFC. If the AFC sees no boost, it'll allow very little fuel.



It revs up in N. Can you build any boost at all in N (5-10 PSI, perhaps)? If not, the turbo wastegate could be stuck open. If you can't build any boost in N, I'll also hazard to say that the engine's rate of (day I say it?) rev gain is not what it was before the accident.



Hmmm. Fender damage. I'll bet a intake heater relay (or both or them) stuck on, heating up the intake manifold and melting the boost line to the AFC, closing it off.

 

[SFPADGETT]

Landshark--the throttle lever and linkage move the same--in Park or Drive



fest3er--I will check the boost hose to the AFC and heater relays. It does build boost in P and N

 

[Missouri Mule]

SFPADGETT, I take it the 28-30 psi is at idle.

Is the fuel pressure being taken before or after filter?

What is the fuel pressure when revved in neutral?

What is the fuel pressure when go pedal is pushed down in gear?

 

[SFPADGETT]

MM--after the filter, fuel pressure is staying the about same (+/- 1-2 psi)--netural and in gear. Yesterday afternoon if started running "normal" and would rev and build speed in gears. This morning it is back to "no rev's" when in gear--but we can now hear a whistle near the AFC boost hose, but cant find a leak in it. (we changed the gasket on the air horn also) I went ahead an ordered a new AFC hose from Cummins --I think we have a bad fitting and during all of the moving and checking of things that the boost hose may have a small leak. I will know for sure Monday morning when we install the new boost hose. I will report back then on the findings

 

[Missouri Mule]

I was thinking if the fuel pressure wasn't going up or going to high while revving in neutral that your overflow valve mite be acting up.



Pressure at idle is good.

 

[SFPADGETT]

Update delayed due to Cummins getting in the wrong part--.



Installed new AFC tube with a little improvement in building rev's (rpm's). Also swapped the overflow valve from one of our other trucks--but no change to either truck. The truck is driving better, but still will not build rev's when in gear--some of the time. Turbo is working fine, as is the wastegate. It still does NOT blow any smoke when is does not build rev's

 

[budnate]

this may sound stupid, is there anyway it sucked a rag into the intake and its all the way over to the grid heaters and has it about choked off now?



most body shops are hacks and dont watch the details when rigs are tore down.

 

[SFPADGETT]

Not stupid--as we all have seen or heard some of the "horror" stories. No rag, or other "extra" item in this case (we had the air horn off and replaced the gasket)

 

[KRStone]

Crap got knocked loose from the jarring of the accident and the dislodged crap made it's way to clogging the injectors..... ? Could anything with the timing have been knocked off in the accident?

 

[surfbeetle]

Since mine's a stick and not an auto, I could be way off. Was the crank position sensor behind the fan damaged? Would it have any effect on anything?

 

[fest3er]

You have air and you have compression, since you can build some boost in neutral. All that's missing is fuel.



Now start moving from the boost line to the p-pump. Is the AFC in good shape? Is the diaphragm in good shape? Is the fuel plate where it should be? Does the fuel rack travel as it should? Do the governor springs function properly?



Get a stethoscope (screwdriver handle to the ear, perhaps) and listen to the injectors and delivery valves. Do they sound normal, compared to a similar vehicle?



In fact, dial your shop air down to 5 PSI and gently apply it to the AFC, engine off, slowly dialing it up to 20 PSI. If you hear lots of air hissing, you'll know what to fix next. If you don't hear hissing, start the engine and, with the AFC at 20PSI, see if you can generate smoke with the trans in gear. Smoke or not, you'll have a better clue where to look next.

 

[SFPADGETT]

KRStone--possible, we have put a gallon of grey bottle Power Service fuel injection cleaner in the tank and it seems to be doing a little better



Surfbeetle--fan wasnt damaged, but we didnt check the sensor. Will check it Monday am



Fest3er--great idea with the shop air, We will perform the tests Monday am. We will also check the fuel plate, rack, etc.

 

[SFPADGETT]

Update: truck is running better after the Power Service injection cleaner; sensor wasnt damaged. We couldnt find any air leaks with the shop air, fuel plate / rack was fine. We are going to check and adjust the timing of the injection pump this morning