1985-1998 [Subscribe to Daily Digest] |
hello there,
My friend has 1992, with some basic performance modifiations done to it. It has the TCS system also, like yours, and in the past all of the TCS parts including the throttle body have been replaced. He had a very srange situation with his car, exactly like what you are describing, and i witnessed it firsthand, while riding in it with him:
Pedal to the floor, only get's around 10psi...
however...
Pedal to the floor, 10psi, THEN take foot off the gas, and RE-floor pedal... achieves full boost, which in his case was 22-25psi on a good day.
We never bothered to figure out what the problem was, because, we figured it was surely some electrical nightmare situation being caused by the di/apc system communicating with the eletronic throttle body system...
basically the throttle body isn't telling the di/apc we're at full throttle, so the apc doesn't send the right signal to the bpc solenoid... was our first guess... could be as easy as a tps sensor, or not... who knows..
but... we had an easy "work around" to the situation, with the pedal, that wasn't so bad... and worked for now...
So far, you've definately done a lot of the work that we should have done gathering information...
from what you investigated, we know now...
tbe bpc solenoid is doing MOST of the things it's supposed to do..
it will limit boost, to base boost, and thus save your engine... which IMHO is the number one most important thing it needs to do.
But, wether the BPC is gunked up on the inside, getting stuck in a position where it feeds pressure to the wastegate... then... we still don't know that.
you can try a working one from a friends car, or remove yours and spray brake cleaner in it, look up my BPC cleanng post a while back.
You say you disconnected your W hose, and only got 10 psi. That is not good, as this becomes a mechanical problem now. That means, the wastegate actuator or wastegate flap is stuck open a little, or intermittently gets stuck OPEN, letting too much exhaust around the turbine... causing it not to spool,
...or you have an exhaust obstruction... possibly in your CAT or muffler... something plugging up the exhaust would increase backpressure an cause a low boost situation.
In my friends car however, since we were able to achieve full boost, we weren't worried about a mechanical problem such as a stuck wastegate or clogged cat.
in your car, i would try disconnecting the w ohse again, not to insult you any, but make sure you have the right hose... i've disconnected the wrong hose before, and freaked out when i didn't get full boost, only to re-check and find the right hose, get full boost, and laught at myself a little... ;) always a possibility.
if you're cruise control system is not on, then i personally wouldn't worry about the cruise control valve. I suppose though, if you really wanted to be sure it wasn't that valve, you could pull the fuse for the cruise control system in the fuse box...
in 1992 the cruise system was completely electrical, as opposed to the vacuum driven systems from earlier years.
Pull the fuse, and the whole system goes down.
might not be a bad idea, 5 second test... who knows you could be onto something, but that wastegate situation should be your first priority.
Check that again, and report back...
-gavin
posted by 74.76.4...
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