AcIdBuRn02ZTS

Hey guys...

Sorry if this is in the wrong spot, but couldn't really find a good area for the questions.

Ive got a 4bta swapped into an '03 Tahoe... its compounded, etc..etc..

Recently the ve pump started leaking so I decided to do a reseal on it. Pulled it apart and went through it without any issue.

Reset everything back to how it was before it was pulled apart (except the gov. shaft... I didn't realize it was adjustable before pulling it apart so I reset it based on memory but its probably not right)

Anyways, reinstalled the pump and it was a nightmare to get it to fire. After I finally got it it start, I had to hold the throttle half open to get it to idle.. which at that point it wasn't missing or anything.. but throttle response was very sluggish.

I asked around and it was suggested that I reindex the throttle shaft.. so I ended up moving it two marks counter clockwise. Now it will start and idle.. but the throttle response and power are still lacking.

I then bumped the power screw in a good bit which brought back some throttle response but now its idling too high even with the idle screw backed all the way out and power is still lower then it was before pulling the pump.

Before pulling it, at idle, I could wrap the throttle up and it would smoke a good bit.. now it barely puts out a haze which means I'm certainly not getting the fuel I was before the reseal.

Where should I go from here??

If this is in the wrong spot, please relocate it.

Thanks in advance.
-Chris

AcIdBuRn02ZTS

Any ideas?

93-12Smoke

Could be a ton of things. So many things could have changed. Throttle indexing could still be off. One click off makes a difference. Are you sure the fuel screw was put back to the same spot as before the rebuild, was the star wheel adjusted? Are you sure the fuel pin is back in the same spot. Do you have the timing in the same spot as before?

oliver foster

Search reindexing throttle shaft.
I am guessing that it is still not right after your re-seal.
Do you get full throttle travel when using the pedal?

I would get the throttle set right before adjusting power screw.
Do you have a Pyro and a boost gauge, or are you tuning blindly?
If you have no gauges, I would install some.
A "compounded etc...etc..." 4BT with a worked pump in Tahoe could be running some pretty hot EGT #s.

AcIdBuRn02ZTS

Yes I have gauges.. EGTs are running cool at idle.

I now have the throttle shaft indexed so far counter clockwise that it idles high even with the idle screw backed all the way out.

Indexed where it is now and the power screw **** near bottomed out, I can only get a light haze out of the exhaust cracking it to WOT... previously it would smoke a bit so I know its not getting the fuel it did previously.

As for timing.. everything was locked down when pulled apart... didn't pull the main shaft out of the pump so it couldn't have moved and I marked the pump body and the timing case and everything lined up dead nuts when the pump went back on.

Throttle shaft index was set by turning the throttle shaft counter clockwise until I could feel the gov. spring, then set at the second notch just like it was done when I installed the spring in the first place which it ran great then.

thrashingcows

Here's the measurement from the face of the body...to the rear of the Governor shaft. This is the stock setting from the rebuild I did on my 93 6BT.



It's 0.310".