turbo overboost

[Guest abweiss]

new problem, under hard accelration it cuts out and catches again, almost like i am talkking my foot off the pedal. then stores code for turbo overboost

What gives? so far i replaced map sensor with no change (dealers idea)

[TwinCamFan]

I'd check the hard plastic vacuum lines. They get brittle and crack over time. I'd say the ones that are suspect are the MAP sensor line itself and the one that leads to the wastegate 'can' mounted on the turbo. The can is what controls your boost level, oversimplified there is a quarter sized flapper in the turbo to exhaust elbow, the rod comeing out of the can attaches to it. Usually when the cans themselves go bad you have very low boost. But if the line that feeds the can has a breach, enough pressure can't get to the can to open the flapper. You might also hook a boost gauge up that yo can see while you're driving so you get an idea of how much boost you are running. Likely more than 14.5 if the MAP is shutting down the fun:o

Alan

[Guest abweiss]

where do i get a boost gauge from? and where do i hook it up?

[Guest abweiss]

update: bought a manul vacuum pump, apply full vacuum to turbo, plunger dont budge, have my frind come by with her 2.2 lebaron put only 10 lbs vacuum and rod moved to the open postion, tried to move mine manually (by hand) it wont move its stuck, what do i do now? how do i remove that turbo? or do i work with the turbo still in the car?

[Bill Reichert]

I think the swing valve is stuck. First disconnect the rod from the swing valve and recheck. Get some PB Blaster and soak the shaft of the swing valve on the turbo. If you read the directions on the PB, it's good/safe to 1,200 degrees. (I think?)

[TwinCamFan]

I think Bill is right, the flapper is stuck/rusted shut. i don't see much of this stuff in sunny/dry SoCal but my back east friends deal with it. I'd do the PB Blaster thing and see if you can work it loose. Did the car sit for a long time recently?

Alan

EDIT: Removing the turbo from the motor by itself is near impossible in my opinion. Some will say they do it, but I pull the whole head to do it on a SOHC motor.

Edited June 22, 2010 by TwinCamFan (see edit history)

[Guest abweiss]

how hard is to remove the intake? if i can remove that I have allot more room to work with, it dont look like she is ready to get unstuck anytime soon

[TwinCamFan]

Honestly, if you're gonna pull the turbo, you're gonna pull the head off with it attached. It's nice to get a fresh valve job and seals etc. But those jobs tend to snowball and take on a life of their own:o

Pull the front motor mount and you can then rock the motor/trans forward (floor jack under the transmission 'pumpkin' differential will do it.) This should give you enough room to get serious about unsticking the flapper.

Alan

[Guest george w]

Don't even attempt to remove the intake or exhaust manifolds or the turbo with the head still in the car. This is a recipe for discourgement. It's almost a certainty that you'll snap off studs, strip threads and who knows what else. 20+ years of age insures that you'll have issues not to mention working clearance at the back of the engine is very limited.

If the PB Blaster or similar penetrating fluid doesn't get the wastegate moving then plan on either pulling the head with the manifolds and turbo intact or driving a very sluggish and slow car !

[Guest My TC Toy]

Ab, To go back to one of your questions, you can get a turbo guage almost anywhere and the hook-up is a simple matter if splicing into a vacuum line and a lighting power source. Some will show boost only, others will indicate boost and vacuum.

Hope you get the problem corrected soon. Good luck.

Bob