Losing boost in 3rd gear...why?!?

[Snorman]

The combo is in the sig. I put on the Powerplate about 2 weeks ago and the IC a few nights ago.
I went for a ride today to check out everything. The car pulls hard and holds ~19psi of boost in 1st and 2nd, shifts into 3rd and drops down to ~12-13psi then starts creeping back up the 18-19psi over about 4-5 seconds. This has never happened. What the heck is happening?
When I put on the plate, the passenger side rear bolt started to turn a bit on me, but it's not stripped and is snug. I double checked all the IC hoses.
Is this maybe a problem with the wastegate solenoid? What should I check?
S.

 

[UNGN]

It could be knock retard. Have you ruled that out with a scantool?

The extra load from the 2-3 shift can cause the car to knock and even a little retard can kill boost.

 

[strikeeagle]

If you suspect the solenoid you might try hooking the turbo up tuner style. Don't try it w/o a scan tool though...

 

[1985GN]

hey snorman i might be out and about tonight if your out ill take a look at it and maybe i can help. if you need help hookin it up tuner style we can do that in 2 seconds thats how i have my car setup. cant remember if you had a scan tool or not. maybe ill see you out tonight

 

[Snorman]

No knock retard. Readings are 780mV and 0.0*.
I really don't think that issue with the plenum bolt has anything to do with this, otherwise it wouldn't hold boost in 1st and 2nd.

Ryan,
I won't be out tonight. Maybe we can catch up this week.
S.

 

[BADINBLACK6]

Same thing happen to me about a month ago, hooked turbo up turner style held boost fine, replaced solenoid and hooked everything back up correctly and all is fine.HTH

 

[Snorman]

It's a new damn solenoid. I replaced it about a month after I bought the car (August).
I'll have to figure out how to hook it up "tuner style" and give it a shot.
S.

 

[strikeeagle]

Tuner style:

A single length of high quality, 7/32" diameter vacuum tubing, running from compressor to wastegate actuator...

Do NOT use windshield washer fluid tubing or the like. It's flimsy, and will collapse, or grow and blow off...

Zip tie both ends for extra security, to avoid k-a-b-o-o-m-s...

Leave the wastegate solenoid plugged in, or it will throw a code...

You can leave the stock wastegate hose assembly (i.e. hoses, elbow, Y) "dangling" from the wastegate solenoid for the time being, until you figure out which way you want to go...

 

[tstolze]

This used to happen to alot of me and my friends, what we found was a combination of the third gear shift with the torque converter locked and some chips pull some boost out on the third gear shift also... This can be solved by shifting into third later, locking the converter later, or by the above threads with the tuner style boost control...