Engine/Transmission (1994 - 1998) low boost/power

[PetesonM]

94 auto new to me. 260,000mi well maintained. I had some "miss" like issues decided to check the timing it was off a little. set it to 15deg + fixd the kdp while i was at it. added tst fuel plate, boost gauge. went for a test drive and the boost is low (10psi) and slow. the wastegate seems to be moving fully and the fuel filter and lines all good. (new and no leaks) intercooler boots good. any thoughts?? lift pump? afc adjustment? would a weak lift pump cause this? still waiting on the egt guage to arrive, but i have an anolog one that i can plum in for now.

 

[fest3er]

Yes, a weak lift pump can definitely cause low power and low boost. Of course, at 10PSI boost, the wastegate shouldn't be opening.

 

[budnate]

your fuel solenoid is probably not opening all the way, willing to bet its about to fall apart, after it is running reach in and lift on it, it will most likely slide up aways farther and open and pull the fuel shut off all the way open or fall apart in your fingers... if you feal it move up then go and lift lift on the valve lever and make may sure its all the way open, then take it for a ride... . should run well.



if its broke order a new one from Larry B. I chose a new one over messing with the old one and on some jerry rig fix last month, I didn't want to be stranded if it chose to crap out again.



lots to read on the subject use the search engine.





B.

 

[KYOUNG]

what is your fuel pressure after the filter ?

 

[surfbeetle]

Did it drive okay before the TST fuel plate? When you installed the plate did you also install the boost elbow (not too far forward or backward)? When you put the new plate in, is it in the same spot as the stock one was? You have to make sure that you have boost coming over to the lift pump from the turbo so that the fuel increases as the boost increases. Also, check all of the intercooler boots on the intake system, make sure they are all tight. Check the exhaust manifold, make sure the gaskets are good and sealed at the head. Change your fuel filter. One last item to check is your valve adjustment.

 

[hsmith]

Make sure the lower inlet to cooler boot doesn't have a hole rubbed in it.

 

[PetesonM]

Working on the fuel press guage now. Not the fuel shut off solinoid. Yes I did move the plate foward a bit could that be it? I will report back with fp readings.

 

[PetesonM]

Fp at idle is 8-10. 15@ rpm

 

[PetesonM]

Fp at idle is 8-10. 15@ rpm

 

[Bob4x4]

You want about 25 psi @ idle should climb some with more rpm,pinch off the return line-if it climbs replace the overflow valve if not and the prefilter is clean possible pump time

 

[PetesonM]

Checked the overflow valve and the spring was broke. got a new one, (21psi @ idle) truck ran better but still low on boost about 15psi. Did some further checking of pump linkage now that I finally had some help out in the shop to push the accel and discovered that the accel to pump linkage was not opening all the way. I spent some time adjusting just right and then went for a drive and power and boost is there now!! this truck for having high miles and a heavy dump box almost moves out like my '99. a few more things to fix and this ol work horse will be ready to clear snow. thanks to all for your help this would have been a long road with out your quick replies.