How much exhaust crackle is normal?
Oct 31, 2007 | 06:25 PM
#1
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How much exhaust crackle is normal?
This is a 22R carb CA model
Ever since I put my LC Engineering catback exhaust on it crackles on deceleration. The motor is a 22R that is bone stock and passed the stringent California smog check last year with good numbers. I have no exhaust leaks; the converter is a year old along with all the tune up parts. I did a leak down test and came back with good numbers the compression is even and within spec.
I tested the mixture control valve this morning and it passed per the field service manuals directions. I'm going to test the fuel decel solenoid this weekend. I'm concerned I might be chasing a problem that does not exist if this exhaust crackle on deceleration is normal with my new exhaust.
Ever since I put my LC Engineering catback exhaust on it crackles on deceleration. The motor is a 22R that is bone stock and passed the stringent California smog check last year with good numbers. I have no exhaust leaks; the converter is a year old along with all the tune up parts. I did a leak down test and came back with good numbers the compression is even and within spec.
I tested the mixture control valve this morning and it passed per the field service manuals directions. I'm going to test the fuel decel solenoid this weekend. I'm concerned I might be chasing a problem that does not exist if this exhaust crackle on deceleration is normal with my new exhaust.
Oct 31, 2007 | 11:48 PM
#4
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Joined: Sep 2002
Posts: 1,555
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From: Sonora, CA
I have a stock exhaust and my truck use to make a lot of popping noises while going downhill or decelerating. It turned out to be a combination of a few things. The biggest was that my vacuum advance was blown. The next was the O-ring on the fuel cut solenoid was dissolved. My EACV was not working either, but the popping seemed to mostly stop after I put on a new vacuum advance and fuel cut solenoid O-ring. The EACV lets air into the exhaust so the cat can burn any unburned fuel, so it may have had something to do with that.
Check that both diaphrams on your vacuum advance hold vacuum and make sure your timing is properly adjusted. Check that all the components of the fuel cut system are working. This includes the vacuum switch that has vacuum at idle and the fuel cut solenoid itself. Also make sure your idle is adjusted properly. Check that the EACV is not shorted and the the reed valve is ok. To do this, pull the lower hose off of the black round thing coming off of the air cleaner and make sure that it has a pulsating suction at idle on the hose coming from under the intake manifold.
Depending on how large the exhaust piping is, it could be normal.
Check that both diaphrams on your vacuum advance hold vacuum and make sure your timing is properly adjusted. Check that all the components of the fuel cut system are working. This includes the vacuum switch that has vacuum at idle and the fuel cut solenoid itself. Also make sure your idle is adjusted properly. Check that the EACV is not shorted and the the reed valve is ok. To do this, pull the lower hose off of the black round thing coming off of the air cleaner and make sure that it has a pulsating suction at idle on the hose coming from under the intake manifold.
Depending on how large the exhaust piping is, it could be normal.
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