So I tried searching google and I can't find my problem. So I purchased the car in April. Boosted 10-8-10 perfect. Occasionally when the secondary turbo kicked in it would hit 12psi for a second then drop back to 10. Then I had a problem with my intake air temp sensor heat soaking. Replaced that with a fast acting one. Now I boost 10-8-12-7. It goes thru the primary fine, drops to 8 then boosts to 12 then holds 7.

Also I drove the car to Point Reyes a few weeks ago and it was a cold foggy day. It boosted 10-8-10 the whole time I was there. Got back into the valley from the coast and went back to dropping to 7.

Car is pretty much stock. Fluidyne radiator, air separation tank, fast acting iat sensor. Has anybody else had a problem like this?

 

I'd suggest you have a solenoid going bad when it gets too warm.

I have exactly this problem at the moment(and for the last year actually).

It can present as zero boost on the secondary - usually after prolonged periods of stop start traffic in +20c weather, or it can present as low boost on the secondary.

Sometimes after cruising at say 60mph for a while, boost returns to normal.

 

What solenoid could it be tho. I was thinking maybe it was the blow off valve solenoid.

 

Turbo Control solenoid - solenoid E in service manual - that'd be my bet.

 

Blow off valve solenoid sounds intuitive, but the blow off valve does not control boost on this car.

I'm with Marf, the turbo control solenoids are frequent offenders.

 

Ok I'm going to have to invest in one a new solenoid. Now the next question is, can I drive it regularly and be ok? It feels fine just a little slow.

 

Yeah no bother, you'll just have no power up top