odd boost problem...stock engine
 

Bone stock 93 touring, stock intake and exhaust.

I just rebuilt the engine not long ago, which is bone stock except for 3mm seals and solid corners for added strength. During reassembly I replaced all the vacuum hoses, any broken checkvalves, and checked all the vacuum solenoids by applying voltage to the terminals to be sure they switched. I'm about as confident as one can be that everything is placed properly under the intake.

The only questionable things are 1) one of the nipples on the front vacuum chamber (behind alternator) was broken, and I glued a vacuum tee type deal onto it (pretty well sealed up) in order to connect the vacuum hose. 2) the car is missing the cylindrical chamber under the intake elbow...it was gone when I got the car. IT doesnt appear to be important, and it's vacuum hoses are laying loose.

The car is otherwise bone stock, stock twins spun freely with very little shaft play. Stock exhaust and intake. The car boosts great sometimes, both primary and secondaries seem to be working well. For instance, in 2nd gear at low rpms I can floor it and I get a solid 9-10psi boost pretty much to redline.

Say for instance, after that hard 2nd gear run with good boost, I shift to third and get right back on the throttle...the car falls on it's ass and I get 1-2psi of boost all the way to redline. If I realize I am not getting boost, let off the throttle completely, then ease back into it, I have full boost again, all the way to redline.

This shit has me puzzled. Searches of the archives/old posts brought up too much information to ever use in a lifetime, and there is not really a way to search for my specific odd problem, so I didnt get any help there.
My intake path is nice and tight, with some aftermarket repalcement couplers in trouble spots. I am sure I do not have a boost leak, though it is possible I could have a vacuum hose off somewhere, or a solenoid making poor connection.

IT doesnt seem to be one of those random things, though...you can bet that one gear/run you will have full boost, and the next you will not, and the next you will.

Anybody got ideas? Thanks in advance.

^

TCA. Not functioing properly and not re-closing the flapper door to the 2ndary turbo once its opened.

See here: http://www.autosportracetech.com/RX-...leshooting.htm under the section entitled "Actuator, Turbo Control."

if it isnt what gt2 said. check the front turbo air inlet flex hose, approx. 3" dia. with ribs. mine was weak and was collapsing during acceleration and did what is happening to you. i solved it by coiling a piece of 1/8" s.s weld wire and snaked it inside to reinforce it . no more problems

that catch can under the elbow goes to the charcoal canister and the purge controll selonoid