rough idle
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ejeffres
- Newbie
- Posts: 11
- Joined: Fri Feb 24, 2012 5:56 am
- My tercel:: 1987 SR5 4wd
- Location: Madrid, Iowa
rough idle
After my 87 starts it idles rough until the engine warms to operating temperature, then all is fine. Does anyone have any experience with this condition? thanks Ed
1987 Tercel SR5 4wd
2012 Chevy Volt
2012 Chevy Volt
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dlb
- Highest Ranking Member
- Posts: 7447
- Joined: Mon Jul 06, 2009 9:03 pm
- My tercel:: '87 sr5, '83 dlx parts car
- Location: bc, canada
Re: rough idle
could be lots of things. first, make sure you step on the gas 2 or 3 times BEFORE starting the engine. i have a hell of a time teaching this to some friends who insist on giving it gas WHILE they start it, and a little bit afterward too. i can then smell the excess fuel coming out the exhaust. stepping on the gas before starting the engine sets the choke, which is crucial to cold engine running.
next, check the choke to make sure it is fully closed when cold, and fully open once warm. set the fast idle using the procedure in the FSM, i think it's in the 'general maintenance' or 'tune up' section at the start. then check the AAP diaphragm on the front passenger side of the carb. there is a simple test for it in the emission section of the FSM so use that. then put a clean hose on the choke opener and choke breaker diaphragms and suck on each one. both should hold air. if they don't, the diaphragms are ruptured and are the source of vacuum leaks when cold. those are the most obvious possible causes that come to me.
the last terc i fixed up would start great, then after a few seconds the idle would start to drop and it would idle crappy for several minutes before coming around and running great after warming up a bit. turned out both the choke opener and choke breaker diaphragms were busted. i was able to replace them with diaphragms from a spare carb i had and it ran great after that.
next, check the choke to make sure it is fully closed when cold, and fully open once warm. set the fast idle using the procedure in the FSM, i think it's in the 'general maintenance' or 'tune up' section at the start. then check the AAP diaphragm on the front passenger side of the carb. there is a simple test for it in the emission section of the FSM so use that. then put a clean hose on the choke opener and choke breaker diaphragms and suck on each one. both should hold air. if they don't, the diaphragms are ruptured and are the source of vacuum leaks when cold. those are the most obvious possible causes that come to me.
the last terc i fixed up would start great, then after a few seconds the idle would start to drop and it would idle crappy for several minutes before coming around and running great after warming up a bit. turned out both the choke opener and choke breaker diaphragms were busted. i was able to replace them with diaphragms from a spare carb i had and it ran great after that.