Let me apologize for the length of this post right now.
So I posted a thread awhile back about what I had thought was a choke problem, and went through all sorts of hell with that. It was fixed... for a little while, but it's acting up again.
Let me first start by giving the symptoms, and then what I consider to be the probable cause.
When I first start the car after sitting, it runs great... for awhile. No stumbling, no flat spots in the throttle, nothing. And it stays that way so long as I never have to idle at a stop light or anything. As soon as I have to sit somewhere for more than a few seconds, the idle becomes rougher, and it sputters and bogs when I accelerate at anything other than WOT.
I took it to a mechanic who hooked it up to... something, and found out that the computer works fine when the key is in the ON position, but approximately 5 seconds after the car is started, the computer shuts off... every time. He told me that it was probably a dead ECM and that it was running in open loop, and was under the impression that the motor was running lean and therefore dumping fuel in like crazy, and causing a rich condition which would explain my symptoms.
So I took his diagnosis and bought a new ECM and plugged it in. Things were absolutely fantastic; like I had a whole new car... for a day or two. Now, I'm under the impression that the same thing is wrong, and that whatever killed my last ECM has killed my new one.
.
Does anyone know what I can check to see what's killing my computer? I have a shop manual for '81 Buicks, and I imagine it's not that much different, and the only thing I got out of it was that it might be the M/C solenoid (mixture control, I guess), but this is a brand new carb, so I'm kind of at a loss.
Also, what exactly could my mechanic have plugged in to monitor the computer status just so I could maybe see if I could see it for myself?
Thanks in advance for any help.
Scott
So I posted a thread awhile back about what I had thought was a choke problem, and went through all sorts of hell with that. It was fixed... for a little while, but it's acting up again.
Let me first start by giving the symptoms, and then what I consider to be the probable cause.
When I first start the car after sitting, it runs great... for awhile. No stumbling, no flat spots in the throttle, nothing. And it stays that way so long as I never have to idle at a stop light or anything. As soon as I have to sit somewhere for more than a few seconds, the idle becomes rougher, and it sputters and bogs when I accelerate at anything other than WOT.
I took it to a mechanic who hooked it up to... something, and found out that the computer works fine when the key is in the ON position, but approximately 5 seconds after the car is started, the computer shuts off... every time. He told me that it was probably a dead ECM and that it was running in open loop, and was under the impression that the motor was running lean and therefore dumping fuel in like crazy, and causing a rich condition which would explain my symptoms.
So I took his diagnosis and bought a new ECM and plugged it in. Things were absolutely fantastic; like I had a whole new car... for a day or two. Now, I'm under the impression that the same thing is wrong, and that whatever killed my last ECM has killed my new one.
. Does anyone know what I can check to see what's killing my computer? I have a shop manual for '81 Buicks, and I imagine it's not that much different, and the only thing I got out of it was that it might be the M/C solenoid (mixture control, I guess), but this is a brand new carb, so I'm kind of at a loss.
Also, what exactly could my mechanic have plugged in to monitor the computer status just so I could maybe see if I could see it for myself?
Thanks in advance for any help.
Scott
