Engine/Transmission (1994 - 1998) Overflow valve or injectors

[Flinty]

'97 4X4 5spd with 309,000 miles. When it's very cold out the truck will not rev past 2000 rpm with any kind of power. It will pull to 2000 then stumble and cut out and send a trail of thick blue smoke behind me at 2000+. Seems like the injectors are dumping fuel but not atomizing it (they are original) or the overflow valve is failing and not enough fuel is being delivered to the injection system keeping it from atomizing properly. What say you guys? My money is on the injectors but I would like to hear from the forum before I drop $600 - Christmas is coming and all that...

Thanks!

 

[Bob4x4]

Test your fuel psi first.then you will have a better idea as to your next step.The 12 valve injectors are very reasonably priced.

 

[KBurgoyne]

Just a theory, but if it wont rev and leaves a smoke trail, that's usually what happens when you hit the rpm limit. If the governor springs are sticking, the pump might think it is at its limit.

 

[GAmes]

How cold is "very cold"? Is the tank still full of summer fuel?

 

[Cummins12V98]

Start with your fuel filter.

 

[CTD12V]

Possibly a timing issue?

 

[Flinty]

Thanks for all the replies. This is the second year that it's done this. The problem will resolve itself as soon as it warms up. The lows are below zero with daytime highs in the teens to low 20s. The truck has winterized fuel in it with Howe's additive. Warming the truck up doesn't seem to help; the issue is intermittent. I will check fuel pressure as soon as I have time and report back. It has been a long time since I changed the fuel filter, though.

 

[Cummins12V98]

Thanks for all the replies. This is the second year that it's done this. The problem will resolve itself as soon as it warms up. The lows are below zero with daytime highs in the teens to low 20s. The truck has winterized fuel in it with Howe's additive. Warming the truck up doesn't seem to help; the issue is intermittent. I will check fuel pressure as soon as I have time and report back. It has been a long time since I changed the fuel filter, though.

Change the filter and report back!

 

[Flinty]

Finally got to the filter today. It seems to have worked, the truck pulls hard to 2700 rpm now. That filter was probably 4 years old! This is the first time in a while where the simple, most obvious fix was the solution. So rarely does it happen to me I have gotten in the habit of going for the more complex expensive options right from the git-go. Thanks for being an extra set of eyes....

 

[Woodenhead]

Good to see you got it fixed. For future reference, if it does it when you bring the RPMs up unloaded (neutral) then there's a good chance it's a timing issue. It happens frequently that the factory timing will slip/retard a few degrees with time.

 

[HHhuntitall]

Lift pump will cause that, too, especially an older one where the spring is getting a little weak, and when it's cold it really doesn't have the snap it used to.... Glad the filter fixed it.

 

[Cummins12V98]

Change the filter and report back!

Did I win anything???????

My truck idled and ran poorly then changed the filter. Runs great now!