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#1
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RPMs fluctuating at startup???
Sometimes when i startup my 1994 Civic EX (vtec) the engine revs back and forth between 1500 and 2000 rpm a few times before finally settling down at 1500 (then dropping lower as the engine warms up). anyone know what might be causing this? |
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#2
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Electronic air control valve (EACV) (idle air control valve IACV on 92-95
Civics) passages may be clogged or have insufficient cooling. Remove, inspect, re-install. Then thoroughly purge cooling system, letting the radiator fan come on two times (may take 35 minutes or more for the fan to come on). Insufficient purging led to my EACV on my 91 Civic having probably no flow through it this past summer and having irregular idling. I took the EACV off, saw its empty cooling line, and purged the cooling system thoroughly. Great improvement resulted. See www.autozone.com 's free repair guides for specific info about the IACV on your 1994 Civic VTEC. Go to emission controls, diagnostic charts, then Idle Control System, 1992-1995. Note that the second symptom listed is "When cold fast idle out of spec (1000 to 2000 RPM)." It lists possible causes to be 1. Fast Idle Thermo Valve 2. IACV 3. Idle adjusting screw Or the oxygen sensor could be going bad, but the oxygen sensor isn't supposed to have much input until the car is warmed up, so I'd check the IACV first. Or other, but the IACV does come up here from time to time as a minor problem. "User38221" > wrote > Sometimes when i startup my 1994 Civic EX (vtec) the engine revs back and forth > between 1500 and 2000 rpm a few times before finally settling down at 1500 > (then dropping lower as the engine warms up). > > anyone know what might be causing this? |
#3
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User38221 wrote:
> Sometimes when i startup my 1994 Civic EX (vtec) the engine revs back and forth > between 1500 and 2000 rpm a few times before finally settling down at 1500 > (then dropping lower as the engine warms up). > > anyone know what might be causing this? =============== How full is the rad, and how full is the reservoir? Ever bled the air out of the cooling system at the nipple? It may even be described in your owner's Manual. 'Curly' |
#4
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One of the sensors going bad.. forget which O2 ?. '92 and 98 Accords did it after
sitting unused for a month. About a 2000rpm swing even after warmup. User38221 wrote: > Sometimes when i startup my 1994 Civic EX (vtec) the engine revs back and forth > between 1500 and 2000 rpm a few times before finally settling down at 1500 > (then dropping lower as the engine warms up). > > anyone know what might be causing this? |
#5
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The O2 is ignored by the computer right after startup.
"RCM" > wrote in message ... > One of the sensors going bad.. forget which O2 ?. '92 and 98 Accords did it after > sitting unused for a month. About a 2000rpm swing even after warmup. > > User38221 wrote: > > Sometimes when i startup my 1994 Civic EX (vtec) the engine revs back and forth > > between 1500 and 2000 rpm a few times before finally settling down at 1500 > > (then dropping lower as the engine warms up). > > > > anyone know what might be causing this? > |
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