Well I'm getting involved in my schools (Cal Poly Pomona) I.C engines lab. They received a donated 99 cummins 24 valve motor from Banks performance to use as a dyno mule for students senior projects. 2 students already did their project on assembling it, adding an air-water aftercooler and hooking it up to one of our dyno's.

They didn't get too far on it because of a dyno issue (pump is from the 50's), they got it idling but said they could open the throttle and the motor would just continue idling basically . They're running just the stock 99 truck injection setup, ECU and all. I'm basically picking up where they left off, I know basically nothing about diesels but I can work my way around EFI pretty well. So anyone have any ideas where to start looking. I assume this system uses some type of OBDII setup yes? Where can I get a good scanner/logger?

Sounds like my 99 cummins did. All of a sudden it wouldnt rev anymore. It was the throttle position sensor. Might not be the same for you. But the voltage wasnt right so wot it didnt even respond

That's what they came up with too, seems weird but I don't know how diesel EFI works yet...

Yep..Most likely you have a APPS issue (pedal position sensor) if the ECM sees is out of range it will default to idle for safety reasons.

Ok cool, they also mentioned that it may be because the security check (from the key). In my experience that shuts down the car completely though... could it be it dis-ables the TPS on this model truck?

What would you guys suggest for tuning/data logging?

Thanks blown . Do you know of any FSM's I can download online for trouble shooting?

Eric
There may be, but since I have all that on hand I honestly have never looked elsewhere to know for sure.

Hopefully someone else can answer that.

Good luck with it

Rick

check throttle position sensor thats what happened to my friends diesel you could push throttle and it would only idle. hope this helps

The rack is also known to stick in those pumps thanx to low sulphur diesel fuel. A buddy of mine was about to replace the pump on his 98 because it was unresponsive to input from the peddle occasionally. Did all the sensor stuff still acted up. He got in touch with a company that remans these pumps locally and was told that about 75% of the pumps he remans really had nothing more than the rack stuck on them. His cure that seems to be working so far is a little outboard motor oil added to the fuel occasionally. Your results of course may vary.

Kevin

HUH ?

The rack is what all the plungers are controlled by which in turn controls fuel. On a non electronic pump the throttle was connected to the rack mechanically. On an electronic pump the ECM controls a stepper motor which in turn moves the rack to add or subtract fuel. The stepper motor has way less power than your foot so if it gets gummed up at all it don't move.

Kevin

Some day when you are bored, take the time to look up how a VP44 actually works.


Rick

I have a good apps sensor from a 2000 . let me know if you need it I will donate it.

Well that is how it was explained to me. I have seen the inside of a few 3406 Cat injector pumps and because they use plunger and barrels with individual fuel lines I assumed the VP44 used a similar arrangement. I saw no reason to doubt what I was told. How the pump works not withstanding, once he added some lubricity to the fuel with the outboard motor oil it quit with the nothing happens when you step on the peddle routine.

If you could post a link to some internal pics and info on a VP44 I promise I won't wait 'till I'm bored to educate myself on its operation.

Kevin

I was sure the pump in my buddies truck had 6 lines in a row on top. It's a 1998 24V IIRC and it's electronic because he has an Edge box on it. If it has the pump in the link on it I obviously did not know from whence I spoke. Thanks for the link.

Kevin