d22019

Is your signature accurate about having a vgt turbo? How is it set up? It sounds like the vanes might be opened too much. Your truck is acting just like my friends 2nd gen 12v when it temporarily had a 21cm housing on it. It would make enough pressure to signal the pump for more fuel but it just couldn't flow the air, which made it barrel smoke at random times. He put a 14cm on it an it runs great now.

1992gen1_fan

JimmieD- I did pressurize the intercooler, it held pressure fairly well but I did not soap and water the I/C its self only sprayed the boots and pvc caps that I used to plug it off. I might pull the grill and look it over again.
I hav'nt soaped the boots and connections in the intake with the engine running because the engine fan just blows the soap off the boots. Maybe I can shield them somehow.

d22019- It is a HE351VE vgt. I set it up to where I can adjust the min. opening and adjustable spring tension against a pneumatic cylinder. I have it about 1/3rd the way open now. I will close it a little farther and tighten the spring some so it takes more boost to start opening the slide collar in the comp housing. I'll just need to keep an eye on the drive pressure gauge

1992gen1_fan

I adjusted the turbo for sooner spool up, which it did but still hard to get 15psi and truck is still a doggg. It will hit 6-8 psi easy, I could probably make that much in 1st or 2nd gear for a second if I pegged the throttle. It just don't want to go above that. There has to be a leak somewhere..
I sure thought replacing the ripped up intake gasket would have fixed it.

Thought I'd add that the drive pressure readings are no different than before the problem started.

BILTIT

Are you still using a functioning fss? I had a bad connection on mine and it would do similar things.

1992gen1_fan

Yea, still have the fss, the connections look good. I have installed direct connectors to it. It shuts off good, maybe its not opening all the way. I might buy a choke cable for the manual kill and gut the fss, would be worth a try

1992gen1_fan

I just checked voltage to the fss. With the ignition on w/o engine running, the battery showed 11.66vdc and the fss showed 10.66vdc.

Theres rite at 1 volt less at the fss, would that be enough to cause problems?

BILTIT

Possibly, i wouldnt think so though. Would be easy to jump 12v to it from the battery and take it for a rip to see.

1992gen1_fan

I'll give that a try

Gizmo52

Did you ever figure out what the problem was?

1992gen1_fan

Sorry I havnt updated this in a long time. I did get the boost leaks prety much fixed, however I do believe my injection pump has some internal timing issues because sometimes it runs great other times not so much. And for the last year or 2 it has developed a miss from about 1000rpm to 1250rpm when there is no load on the engine.

At the moment I've been trying to trace down a small air leak in the fuel system with no luck.

Gizmo52

Check the rubber lines at the lift pump I've had a dryrotted return line and it's given me that problem. Also I've had a problem where my fuel pin sticks down and causes it to lobe real bad so make sure that's not sticking either. If you have no fuel leaks I'd check all the return line connections too

1992gen1_fan

I'll check the return line, thanks
The fuel pin seeps to be working fine, I actually just installed a new fuel pin and verified the little slide pin that rides the fuel pin profile is moving freely.

Gizmo52

Just wondering what is your fuel pressure at feeding the injection pump?

1992gen1_fan

With the high volume piston pump at idle the fuel psi stays in the 14-15 psi range, I cant pull it below 9-10psi usually with the extruded stock injectors. That's psi after the filter btw

Gizmo52

What lift pump are you using?