1979-1993 & 94 Conv [Subscribe to Daily Digest] |
Let's see if I can describe this one clearly. I've had the need to check and/or replace the voltage regulator. Only problem was accessibility because of the location. I decided to remove the intake manifold for easy access. I've done it before - general cleaning and replacing of the gasket - with everything going back together without a hitch. All went fine this time... until I started the engine after reassembly. Then all hell broke loose. A very high idle to start with, then a gradual lowering accompanied by what sounded like one or two of the cylinders losing spark (chugging). It eventually sputtered to a halt. Restarting was fine, but it would only stay running at a high idle - above 1500rpm. Just to be able to keep the engine running while I investigated, I had to set the idle high. I thought at first the obvious - I'd forgotten to connect one of the vacuum hoses. But everything was sound. Nice and tight. No hissing or whistling sounds that usually accompany a vacuum leak. All elec connections are fine.
There's also a "lean" burn exhaust smell (as opposed to the rich burn smell). From what I can guess, the ECU thinks I'm running rich, and sends an overly compensating lean signal to the modulator valve, which is only noticed at idle. When driving at normal speeds, the engine runs fine. Acceleration is normal.
Anything come to mind as to what this could be? Does anyone know of any one component or ECU signal source that can cause this symptom? I'm gonna head out to disassemble and reassemble the manifold once more, paying close attention to any and every connection. I'm also going to disconnect and check the ECU connector plug beneath the rear set. Perhaps this will also reset the unit? I also have another working ECU as a substitute if need be.
Thanks in advance!
posted by 64.12.1...
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