Backfire on deceleration

[al shapiro]

I have an occasional hellacious backfire from the exhaust when I take my foot off of the accelerator after getting on it. Does anybody have any ideas? Thanks.

 

[pdzz]

Check the cam sensor. Make sure the tab is intact.

 

[dank GN]

Make sure the cam sensor is properly installed and didn't move

 

[al shapiro]

Thank you for the reply. I recently changed the cam sensor cap trying to detect a problem that ended up being the Big Stuff 3 ECU. DO you think the cap that I put on can be bad?

 

[al shapiro]

It wasn't a new cap

 

[pdzz]

Not the cap, the reluctor. That little tab that indexes it, breaks off, then your injector timing is off, then backfire.

 

[al shapiro]

I kind of remember replacing that tab with a stronger one that was connected to a washer underneath the cup. Anyway I will check it. It does seem weird because I just swapped cam sensor caps and now I have this problem. Does the cap ever go bad? And what happens if it does go bad? How would it act? Again, thanks for the help.

 

[al shapiro]

Do you know who sells that tab these days?

 

[pdzz]

Yes, caps go bad. RJC racing.

 

[dank GN]

Is it adjusted correctly 25* ATDC ?

http://www.vortexbuicks-etc.com/cam_sensor.htm

 

[al shapiro]

Yes. It was running perfect and then one day it just died. I never touched the cam sensor itself but I did change the cap (with another one that I had laying around) to see if that was the problem. It's got Big Stuff 3 engine management and the ECU fried something inside. I had to send the ECU back to Big Stuff. I got it back and now the car starts but now this problem.

 

[TurboTdr3.8]

Have you looked at the spark plugs ?

 

[al shapiro]

Well changed out the cam sensor cap with the original one that was on it and problem is solved. I guess the cap was bad. Thanks again for the info. You guys are the best.

 

[dank GN]

glad to hear it