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Ok, here is the problem: I'm only getting half boost. The car is a 1991 CS Carlsson auto 2.3 with APC/DI.
Here's what I've already done:
1. Checked all the vacuum hoses. Look good.
2. Took the W vacuum line off the APC solenoid. I was getting plenty of boost that way, so turbo is ok.
3. Reconnected the W hose and unplugged the APC solenoid. Again plenty of boost. However, I read in several posts and websites that disconnecting the APC solenoid should give me only base boost, I was getting full boost as in (2).
4. Checked wastegate rod. I took the rod off, unbolted the exhaust so that I could see the wastegate. Looked ok, but had quite a bit of free play. I haven't seen another one so I can't comment any further.
5. Checked bypass valve by blowing/sucking in the small vacuum pipe coming out the rear of the valve. No leaks there.
6. Checked spark plugs. Regapped them. No effect.
7. Checked APC voltage, resistance and air flow while on and off. It is definately working, it is buzzing hapilly. Everything is normal.
8. Sprayed APC solenoid with suitable lubricant/cleaner. No effect.
What I haven't checked yet:
1. Knock sensor. Couldn't find the bloody thing! Found two connectors behind the engine, under the manifold and behind the starter motor as someno suggested. One had a single wire, the other more than 2. Is it one of those?
2. Brake pedal switch. But since the cruise control is working, I don't think it's that.
Can't think of any thing else to check. I suppose I could try another DI casette and see if it does the trick. However, I doubt this is it...
I'll try to find another APC solenoid to check with. However, mine has passed all the tests. Could it still be bad?
Observations:
1. While on axle stands, I had someone rev the engine while I was looking at the wastegate actuator. Boost went up to atmospheric pressure, and I could see the rod moving to the end of its travel. Is that normal, or should the wastegate remain closed for longer?
2. I cannot understand why disconnecting the APC solenoid should give you base boost. How would the wastegate open in order to reduce the boost without the APC solenoid? It looks to me that the wild boost I'm getting without the solenoid connected is correct.
Is there anything I've missed? I could use a few good ideas....
I'm sorry for the long post, but I really want to get my Carly sorted!
Thanks in advance
Harry
posted by 194.117.133...
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