Ask Experts Questions for FREE Help !
Ask
    BnNC's Avatar
    BnNC Posts: 2, Reputation: 1
    New Member
    		  
    #1

    May 28, 2008, 12:39 PM
    1989 Honda Civic Si - Erratic Idle
    The motor will idle down low but never cut off, then correct itself and do it again. Can't tell what the RPM actually is because the tachometer is erratic and all over the place. The motor runs good, just idle issue. Would like to know how to fix both the idle and the tachometer.

    BnNC
    TxGreaseMonkey's Avatar
    TxGreaseMonkey Posts: 16,761, Reputation: 5597
    Uber Member
    		  
    #2

    May 28, 2008, 01:14 PM
    . Erratic tachometer readings can be caused by a failing Ignition Control Module (ICM); therefore, test/replace the ICM:

    https://www.askmehelpdesk.com/cars-t...tml#post265896

    . Ensure the Idle Air Control Valve and hoses are clean:

    https://www.askmehelpdesk.com/cars-t...ml#post1054149
    BnNC's Avatar
    BnNC Posts: 2, Reputation: 1
    New Member
    		  
    #3

    Jul 25, 2008, 11:28 AM
    Quote Originally Posted by BnNC
    The motor will idle down low but never cut off, then correct itself and do it again. Can't tell what the RPM actually is because the tachometer is erratic and all over the place. the motor runs good, just idle issue. Would like to know how to fix both the idle and the tachometer.

    BnNC
    That fixed the tach... thanks
    I cleaned the ACV, which wasn't dirty. Still having the idle issue. Could it be an O2 sensor or vacuum problem?
    TxGreaseMonkey's Avatar
    TxGreaseMonkey Posts: 16,761, Reputation: 5597
    Uber Member
    		  
    #4

    Jul 25, 2008, 11:45 AM
    See if this link helps:

    https://www.askmehelpdesk.com/cars-t...tml#post842969

    Yes, vacuum leaks could definitely cause the problem you describe.

    . Clean throttle body.
    . Run a compression test on engine to check valves and rings.
    . Adjust valves.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

1996 Honda Accord erratic idle [ 5 Answers ]

I have a 1996 Honda Accord. I recently had a problem with an extreme erratic idle. It seems to only do this when the engine is cold. Once the vehicle warms up, It returns to a normal idle. I recently replaced the spark plugs, oil, anti-freeze, and air filter, which had no effect on the...

1986 honda civic erratic idle [ 4 Answers ]

I have a 1986 honda civic that won't idle periodically. Never happens when its cold. Sometimes it runs perfect. At all other speeds it runs perfect. No missing, etc. its only the idle. When it does act up the minute I push the clutch in the tach needle falls down to zero and the car stalls. It...

Honda civic erratic behaviour [ 2 Answers ]

I have a 1995 honda civic with a 1.6 sohc engine (D16Z6) and sometimes when I try to start it the engine turns over but won't fire, then I stop turning the engine after about five turns and try again and it starts reluctantly, if I rev the car up to 1500 rpm it starts to fluctuate but above or...

1989 honda civic [ 5 Answers ]

On the crankshaft, is the bolt reverse theaded or normal

View more questions Search