I'm looking for help on a strange issue that we've been trying to stop for quite some time.
83 Hurst Olds, original drivetrain, no rebuilds, 42k miles.
Brought it in to have a number of things fixed, to include valve cover gaskets, a leaking transmission, TCC solenoid, and a peculiar surging issue.
The mechanic buttoned it up and I drove it home, but I found the surge was still there. When just holding the speed at 30, 40 or 50 there is a surge/ inconsistent engine feel. It's always within the 1000-1500 RPM range. You don't have to be driving, it'll do it when parked as well.
I brought it back and he had me test drive it with him to demonstrate. I left it there and he has been trouble shooting ever since.
I had already replaced the O2 sensor and MAP sensor. He pulled the vacuum off the MAP sensor and saw fuel in the line. He traced back to the carb.
The carb had been replaced, and he pulled it off to check it out. What he found was that the base plate was bent, and under certain circumstances was sucking fuel into the vacuum system. I was able to find an original 83 HO carb to replace this and be back to the numbers matching carb on the car, which was a bonus. Mechanic rebuilt the 83 Carb. Still no joy, the surge issue was still there.
Car was running excessively rich, and he figured it could be the ECM. Replaced that, no joy. He is going to replace the O2 sensor next but is running out of ideas.
What else could cause this?
83 Hurst Olds, original drivetrain, no rebuilds, 42k miles.
Brought it in to have a number of things fixed, to include valve cover gaskets, a leaking transmission, TCC solenoid, and a peculiar surging issue.
The mechanic buttoned it up and I drove it home, but I found the surge was still there. When just holding the speed at 30, 40 or 50 there is a surge/ inconsistent engine feel. It's always within the 1000-1500 RPM range. You don't have to be driving, it'll do it when parked as well.
I brought it back and he had me test drive it with him to demonstrate. I left it there and he has been trouble shooting ever since.
I had already replaced the O2 sensor and MAP sensor. He pulled the vacuum off the MAP sensor and saw fuel in the line. He traced back to the carb.
The carb had been replaced, and he pulled it off to check it out. What he found was that the base plate was bent, and under certain circumstances was sucking fuel into the vacuum system. I was able to find an original 83 HO carb to replace this and be back to the numbers matching carb on the car, which was a bonus. Mechanic rebuilt the 83 Carb. Still no joy, the surge issue was still there.
Car was running excessively rich, and he figured it could be the ECM. Replaced that, no joy. He is going to replace the O2 sensor next but is running out of ideas.
What else could cause this?
