Engine/Transmission (1994 - 1998) No power up to 1700?

[TJarecke]

Working on my brother's 94. He just bought the truck. It has ~185k. I was asked to work on it because it was blowing white smoke. I assumed that this was caused by a weak lift pump and stock timing. I adjusted the timing to 16* and the smoke went away. While I was there I did some other modifications. Afc spring, ground the plate to a 100 (set in the middle), and put in 4k springs.



The truck starts fine idles fine and has some power 1700 to 2900. No smoke at all. Below 1700 it has nothing. You can put it in 5th and lug it and it will not go any faster? And again no smoke.



Could this be a weak lift pump causing this or is there something else that I am missing?

 

[hsmith]

If there are no leaks, I would go for the overflow valve. May have broken spring.

 

[GAmes]

I think it is the timing. When I changed mine to 15. 7 the torque curve moved up a little and the engine bogs at 1700. For that reason I tow at 1900 rpm for the best mileage.

 

[Vaughn MacKenzie]

What AFC spring did you do. . . if you put in a stronger one then it's not letting it fuel much until you get a fair amount of boost. Try adjusting the starwheel full forward. Timing is at 16 deg on my '98 and it has good power by 1300-1400 RPM.

 

[TJarecke]

I will have him adjust the star wheel. I don't believe it is the timing. It has NO power below 1700 not just a power band increase. I will have him check the overflow valve too. Start eliminating things anyway.