GnubberLang

Hey, sorry I searched around and didn't find much information. I've got a occasional exhaust "pop" noise, Not really sure what it is, it's not really very loud or regular but the idle hesitates when it happens. It's like... pop....pop pop.... pop ... poppoppop.............pop. Thing sounds great when it's revved though, stops the popping anywhere above 3k. Going to test TPS right now but what else could cause this?

go_jesse

iTrader: (1)

I have a similar question, not trying to hijak thread :-) 86 base model

I get popping at 1000-2500 RPM (maybe higher) with no load. At idle, no pop. checked my timing, it might be very very very slightly advanced.

I have yet to try the fix the joints in the cpu, thinking that is maybe next.

BlaCkPlaGUE

If you've checked the timing, why not put it dead on?

Popping in the exhaust is either

1)timing
2)TPS out of adjustment

It can also be related to the dashpot, but im certain that if you check the above two and get them to spec, you won't have any more popping.
If your unsure how to change the timing jesse, but only know how to check it, all you have to do is loosen the one nut on the crank angle sensor. Its that cylinder thing sticking out of the engine at an angle with a wiring harness near it. Loosen the bolt and physicall twist the whole sensor left or right. Using the timing gun on the L1 lead, match up the SECOND mark on the pulley (the mark that is furthest away from you) with the light. Tighten the bolt, check again, your finished.

tps adjustment can be found at www.fc3spro.com, really easy to understand.

go_jesse

iTrader: (1)

thanks for the response, timing is now dead on. Still pops. I'll check the TPS, the link you sent is for the turbo, but i can figure it out.

BlaCkPlaGUE

The turbo and NA are the same. I should have asked what year your car was? if its an 89-91 then your TPS is quite different.

I can't find a guide for the series 5, but if you have a haynes, check in there. You should have a haynes if you own a seven... seriously

Finally check out the FSM on the dashpot adjustment. The linkage should start to touch the dashpot at like 2700rpm

Do this after the tps is adjusted.

good luck.

*edit*

Finally, there is a solenoid on the ACV that pumps air into the intake after the throttle plates close to prevent afterburn during this rich condition. (plates closed, no more air, but still fuel left).
Anyways there is a test in that FSM as well to make sure that its working. The air pump is the source of the air BTW.