HELP! my engine is surging at idel. why?
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Burning Brakes
Joined: Oct 2006
Posts: 1,006
Likes: 28
From: Lutz Florida
Make sure your timing is right. Make sure the carburetor is adjusted properly. Check for vacuum leaks.
If the car was running ok and then just started this, check the vacuum advance like others have suggested. If that is not it, then start looking for vacuum leaks. A vacuum leak can cause surge at idle. Is you car an automatic? Check down at the vacuum modulator on the transmission to see if the small piece of rubber vacuum line that connects the modulator to the steel line that runs up to your manifold port is cracked or got knocked loose. That will cause a surge condition for sure. After checking everything else on mine thats what was causing it. Naturally it was the last place I looked....
Good luck finding it.
If the car was running ok and then just started this, check the vacuum advance like others have suggested. If that is not it, then start looking for vacuum leaks. A vacuum leak can cause surge at idle. Is you car an automatic? Check down at the vacuum modulator on the transmission to see if the small piece of rubber vacuum line that connects the modulator to the steel line that runs up to your manifold port is cracked or got knocked loose. That will cause a surge condition for sure. After checking everything else on mine thats what was causing it. Naturally it was the last place I looked....
Good luck finding it.
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Instructor
Joined: Nov 2006
Posts: 115
Likes: 6
From: Carlyle IL
Ive heard that if you store a car with winter gas the car will idle or act diffenerntly depending on the temperature and humidity when you start it up the first couple of times right out of storager. The same would be for summer gas in the winter. Has anyone else heard of this?
Burning Brakes
Joined: Dec 2007
Posts: 952
Likes: 0
Your right. I have capped all ported vacuum ports for so many years, I forgot people still used them.(God knows why)
