[black_k5]

i have a 91 with an auto, the truck has just lately been idleing all wierd. it will idle fine then sometimes it will just drop down to like 300 or 400 rpm. there doesnt seem to be a lack of power anywhere in the rpm range, it doesnt studder or cough. the fuel filter got clogged about a month ago, would that have anything to do with what its doing now? any ideas? thanks

 

[Cummins 67]

:welcome::welcome::welcome:

Fill out your sig so we know what you have.

Is there alot black some coming out when idling?

 

[black_k5]

no it doesnt smoke any at idle. and runs perfect at any other rpm.

 

[Cummins 67]

The easiest thing to try is to run injector cleaner though your engine and see if that helps.

It almost sounds like you have dirty injector or a leaking one.

If your fuel filter stopped up it is very possiable that is what is going on.

 

[black_k5]

i have some in the tank right now, ill keep running it and see. thanks for your help!

 

[Cummins 67]

No problem.

I would put 7gals of diesel in your tank and run 3 bottles of cleaner.

The otherthing you can due is put one 16oz bottle of rubbing alchol to 10 gals of diesel.

Just dont do it alot. If you do it will dry out the rubber seals, but it is good to get any water out of the fuel system.

Also note for people with newer trucks. I dont advise using rubbing alchol at all.:thumbsup

 

[duckfamily]

I just purchased a 91 in Michigan. Drove it all the way to North Dakota with no issues. The only thing is it runs really rough @ idle other than that it was a perfect trip. Any help would be great?

 

[Greenleaf]

I will reply to each of these........

black_ You have home work to do. The last thing to condem is an injection pump so check everything leading up to that. Fuel leaks, lift pump supply psi, throttle linkages etc. even the TV Cable op.

Do you know Piers Diesel? They be near you. They know the first gens REAL well!

The pump can begin self destruct mode and act as you described. If you catch the problem early, you can save it and about a thousand $ with a seal kit and some internal springs.

To say that HP is not effected: if you have factory HP then you likely will not notice. If you have engine performance where it should be (400-450 HP) you will notice a difference.

...and Ducky. If your engine runs fine and seems loapy at slow idle speed, your injectors are out of sorts. This could be wear, dirty, OR new injectors that are not set to the same bar (pressure) They must all be the same or very close to one another. :thumbsup

It pays to have the injectors set by a shop. Sure,,,,,, new injectors are a help, but if they don't calibrate them to all the same pop-off bar, then they never will act right. :thumbsup :$:

Scott

 

[duckfamily]

Thanks Scott, I dropped it off at my local diesel shop this morning. He concured with you on the injector issue. He also said that it could need the valves adjusted. I will post when I get it out of the shop. Thanks again.

Ducky

 

[duckfamily]

Got my truck out of the shop. Bad injectors, ordered BD 40hp+ to replace. Valves were real loose, new fuel filter, and turned up the idle a touch. Already much better. Can't wait for the new injectors next week. Another note; I renewed my Premium Membership today. Sites like these have saved us many many $$$$$'s. If you have benifited from a site such as this, PLEASE PAY YOUR DUES. Thanks to all the good people.:thumbsup:thumbsup