lower boost after increasing fuel

[hamold1]

:confused:Had 11 psi boost before today...just turned the metering screw not quit 1/4 maybe 1/8-3/16 of a turn then drove the truck...boost was down 6-7 psi...I've got a performance waste gate acuator????? ,4" exhaust, performance air cleaner, new delphi injectors(stock) 1993 mech ip....Any thoughts?

[Hubert]

Notice any change in smoke during moderate throttle?

My first quess is that turning up the fuel actually increased boost and you opened the wastegate faster or more than its use to and now its stuck slightly open and or just not sealing like before. Early models had a problem with pivot shaft of wastegate woller'in out the bore and then has some binding issues might be it too and this change brought issue out.

Could be a piece of soot or carbon blocking the wastegate from seating etc.

[Hubert]

2nd thought... Something about the "turn up screw" has an affect on base timing and you could have gotten it out of range of good time.???

[Hubert]

:I've got a performance waste gate acuator????? ,4" exhaust, performance air cleaner,

To be clearer I should have said it like this....

What is it? Similar to a Turbo Master or other? I know when I initially set my TM it took a while to settle in and I had to readjust it once or twice over a day or 2.

Like I said before you increased fuel and more than likely increased the back pressure on the turbine and pushed on the wastegate different than before so it might be as simple as resetting it and seeing if it will resettle in at 11 psi Just the wastegate opens farther now than before because of ineffeciency of turbo. You are burning more fuel and making more power but limiting boost by wasting turbine drive pressure. You might just need to readjust to this new drive pressure. It shouldn't be lower boost but you may some type of hysterisis going on with wastegate mechanism.

[JohnC]

Are you sure you turned it the right way? You should have either more boost or more black smoke or both. Otherwise, you can't have more fuel...

[hamold1]

I've got a little black smoke now on accel, I turned it clockwise....my timing was slightly advanced before this....