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This one sure attracted a lot of attention... Posted by Ari [Email] ![]() ![]() In Reply to: why can't I get into the RED??? (Anders? Ari? help), nt moore, Thu, 7 Mar 2002 19:21:19 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I've read a few of the other posts, but I suspect I'll be repeating some here.
Normally, you should be able to get to the top of the yellow, maybe just touching the red. The turbo boost limiting there isn't exact, and neither is the boost gauge. The boost limiting is set by the wastegate and wastegate rod length, and the boost pressure gauge is a spring. Remember, we're not talking calibrated, precision instruments here.
Here's a very simple way to tell if you're in base boost - find a nice, long uphill, and hit it at about 45 mph in third gear or so. That should be over 3K rpm, so you should be getting full boost, or as close to it as the system allows. Now, with your left foot, LIGHTLY touch the brake pedal - enough to get the tail lights on, but not to engage the brakes. See if the boost gauge drops any.
When the brakes are on, the system drops into base boost. If you see the boost gauge drop some when you hit the brakes, then you know you aren't being limited by the APC system. If you see no change in the gauge, then you probably are in base boost. This trick works OK for the older cars like yours, as the APC didn't modulate the solenoid. Somewhat different for later years, but similar.
If you aren't in base boost and aren't getting full boost, AND you've fully checked out the rest of the system for leaks, run good gas, and have a well-tuned engine, then you might think about adjusting the wastegate linkage. But before doing that, I would get a decent vacuum/pressure gauge, and check the boost pressure against the engine spec (which I don't know off the top of my head, but could find). Remember, the dash boost gauge is not a precision piece of equipment.
IF you are running at less than spec boost, and you're not in base boost, then you can increase the boost level to spec by SHORTENING the wastegate rod. It's a rod from the wastegate to a lever under the turbo. The rod connects to the lever with a cotter pin. Remove the pin, and screw the rod in about 1/2 turn or so. The rod screws into a nut welded to a diaphram in the wastegate actuator. It is IMPORTANT to hold that nut steady with a wrench while you screw the rod in or out - otherwise, you risk damaging the diaphram. Reconnect, and go for a ride with you calibrated gauge. If you did too much or too little, wait for things to cool and adjust again.
Remember, this is a now 15 year old car, probably well north of 100K miles on the clock. Don't expect it to run the same as two weeks out of the factory. And just like a 90 year old man with a 19 year old wife, be careful of turning up the wick too much.
If you are in base boost, check the archives - there are LOTS of posts on the subject. The first thing I would do is make sure the APC solenoid energizes - at idle, unplug and plug the electrical connector, and listen for a click. That tells you there is power there, but doesn't mean the solenoid is working. Neither does measuring the resistance. There are three lines to the solenoid, see the posts, but you should be able (or not able) to blow air through various lines depending if the solenoid is energized or not. Do that test, then move on.
It's a start, anyway.
Good luck!
posted by 140.157....
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