Engine/Transmission (1994 - 1998) symtoms of worn out injectors?

[jeffg]

looking for advice on a 98 3500 5 speed 12 valve with 260k. This truck spent its 1st 200k delivering rv trailers. (breaking in) ha ha.

It now runs hot and does not idle well or start well without some

throttle. I know the injectors are original and the valves are in need of adjustment. would worn/clogged injectors and/or out

of adjustment valves cause these symptoms? any other Ideas?



thanks for any replies

 

[JJW_ND]

I doudt your injectors are bad.

Unless the previous driver was very obusive and skipped on maitenance, your engine should be very clean and mecanically in excellent shape. Hottshotting or running RVs is as good as gets for these engines. No short trips. Always up to operating temps. Many many miles of straightline nonstop driving. Most fo the return trips are bobtail so no load yet many hours of straight through easy driving.



I think you just some adjuments to make sure everything is still set right. A good radiator flush and coolant change might help the heat problems.



The idle and poor starting should be cured by setting your idle up to 850 - 900 rpms or just increase it a little. Idle adjustment is pretty straight forward. Run a search on idle adjustment to find everthing you need to know. These 12V start much better and never die out with a little higher idle setting.



jjw

ND

 

[jeffg]

Thanks. Its good to know the injectors are not at

fault.

 

[bmoeller]

http://dodgeram.org/tech/dsl/adjustments/2nd_Gen-Idle.htm

 

[Deezul1]

Sometimes the fuel return line gets bad enough to allow air in to the fuel sytem but not leak and this can cause hard starting

 

[jeffg]

I appreciate all the info.

 

[BWilson]

I had the sam eproblems with mine and just bumped the idle up. It cured everything. I was actually hoping the injectors would be worn so I could justify the new ones to the wife! Oh well, at least now I know all I have to do is dial the idle down and show her how hard it starts

 

[dpuckett]

The only way to tell for sure if your injectors are worn out is to remove them and have them pop tested by a shop with a test stand. Not sure of the pressure of the newer 12 valves, but the spec on 1st genns is 3550 psi. My 91 has 250K+ on the originals, and 5 were popping at 3200; on couldnt hold 300 psi. I had a 93 a few years ago that was 2800 psi at 140K. Got em cleaned and recalibrated, and gained 2. 5 mpg. Just depends on maintenace and driving habits. If you can live with the smoke and MPGs, I wouldnt worry too mcuh about it. I would look at return lines, lift pump, overflow valve, etc, like others have mentioned.



Daniel