Engine dies when you tap throttle...sumtimes

[86trbolancer]

My buddies '97 2500 2wd auto...

Only maybe every 10 or 20 starts when you tap the throttle it will die...starts, runs, and drives fine. I've already changed his ff...So I'm assuming its one of the solenoids or that fuseable link

Can I get some ideas or ways to verify the problem please

Thanks

Ryan

[shadow88]

What's the idle speed? It should be around 700 in gear or about 750 with a stick.

[03 3500]

go to www.cumminsforum.com (http://www.cumminsforum.com) i have a cummins and its the best site for the 1st gen upt to the 4th gen cummins. they will help you out

[jonnyb]

That's actually normal for the 12V engines. When the motor is cold it chokes itself off a little bit (just like any other vehicle on a cold start), and those year diesels with the mechanical pump can't seem to handle a cold throttle blip very well. Now, if it does it when it's warmed up, then you probably need to make an idle screw adjustment to bring the idle up a bit.

[86trbolancer]

Thanks for the replys guys!!!

I'll have to check what idle is at, but i'm pretty sure its good. It's an auto btw. It isn't really cold where the truck is at, but it definitely does it more/easier when its cold.

I'll check idle sometime in the next week or so when I get up to the ranch again

[Subliminal]

That's actually normal for the 12V engines. When the motor is cold it chokes itself off a little bit (just like any other vehicle on a cold start), and those year diesels with the mechanical pump can't seem to handle a cold throttle blip very well. Now, if it does it when it's warmed up, then you probably need to make an idle screw adjustment to bring the idle up a bit.

Interesting...I've never experienced this.

[shadow88]

Probably because your idle is set correctly. I have never found something that's repairable by following FSM idle setting procedure to be normal.

The reason why it affects these trucks with age is the paint on the idle stop screw wears away causing the throttle linkage to close too far. That screw needs to be readjusted to compensate for the thickness of the paint. It's a one shot deal.

[jonnyb]

Interesting...I've never experienced this.

I should probably clarify, I've seen it happen on every 94-98 12V I've checked out. I'm pretty sure the fuel delivery system is different on your earlier 12V so whatever causes it may not be present on your truck Damon.

Also, I've never really checked out/drove one of these when they were new and most that I have been in were around the 200-300K mile mark, so if shadow88 is right about his description of why it happens (sounds like a wear item is the cause), then that would make sense as to why it seems "normal" to me....LOL!

[shadow88]

It's adjustable with 2 10mm wrenches. I haven't done it in a while, so I forget the exact procedure, but it's basicly a stop screw and a jam nut, both 10mm sized. It only takes about 1/8 to 1/4 of a turn counter clockwise. Once you locate the stop screw on the rear of the injection pump it's pretty straight forward. Adjust tiny bits at a time.

Edit, that link to cumminsforum probably covers it in detail.

[Evilancer]

I should probably clarify, I've seen it happen on every 94-98 12V I've checked out. I'm pretty sure the fuel delivery system is different on your earlier 12V so whatever causes it may not be present on your truck Damon.

Damon's truck has a Bosch VE pump. The truck in question has a Bosch P7100 pump.

Jon

[shadow88]

^^ Good catch. I didn't take note of the year of Damon's truck.

[DOHCRT]

www.TDR1.com

[Subliminal]

Right...totally different fuel pump...when you said 12v, though, I figured I'd jump in. ;)

[86trbolancer]

well i bumped up the idle and it runs fine now thanks for the advice guys!!

I also learned of the killer dowel pin. How i'd never heard of it before it don't know. anyway my buddy has had a bad oil leak for a long time in this truck so i get a frt timing cover gasket/seal kit. Figured it had to be one of the gaskets or the frt crank seal leaking. Well nope. Right under the bracket the fan attaches on to top side of the frt cover was a big hole. The dowel pin had came out, rolled over the gear, jammed between the aluminum housing popped the hole, rolled down and when i got the cover off was just sitting between the crank, oil pump, and cam gears. I was told this usually cracks the block.

[Evilancer]

Damn that sucks man, but yeah that is just some of the carnage that can happen when the pin comes out. I'm pretty sure the block should be ok, but the gear housing needs replacing now for sure, wich is a pretty involved job.

Jon

[shadow88]

Glad you got the adjustment right. It shouldn't ever happen again.

[86trbolancer]

Damn that sucks man, but yeah that is just some of the carnage that can happen when the pin comes out. I'm pretty sure the block should be ok, but the gear housing needs replacing now for sure, wich is a pretty involved job.

Jon

Eh, its 600+ for the frt cover. I just JB welded it, put the frt cover back on, and put some gasket sealer over the jb weld where it met the front cover. Hasn't started leaking yet !!! FINGERS CROSSED


Glad you got the adjustment right. It shouldn't ever happen again.

Thats what i'm hoping :)