Mechanics

FLUCTUATING IDEL SPEED

1997 Honda Civic

Engine Performance problem
1997 Honda Civic 4 cyl Front Wheel Drive Manual 96,000 miles

I have an 1997 Honda Civic DX just did a motor swap using the same motor type and old wireing harness. Runs great and has a lot of power, but dosen't want to keep a consistant idel after the car is warm. The car runs high when cold like it soposed to but when it gets warm and wants to kick down the idel goes up and down.
Please help me!
Jeff Ward
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JWard56
June 9, 2010.



Did you use the old intake that was with the car? This will eithe rbe the idle speed controller is sticky from sitting (if used the one off the salvage motor) or the air bleed screw has backed off. The bleed screw is on the throttle body and I have seen them vibrate out and cause what you describe. The Idle speed controller will do the same, you can remove it and try cleaning it with carb cleaner to see if it will work again. Als be sure there are no vacuum leaks

Tiny
Jack42
Jun 9, 2010.
No the motor came from TX and came with the intake manifold and carb on the motor. I did a vacuum test and it's below specs any suggestions? I'll try looking for the bleed screw didn't even know it had one. Thanks Oh is the idle speed controler the same as the mass air flow sinser? It's wierd because if I unplug the mass air flow sinser while the car is running and plug it back in the car idles great but does the same thing after I turn the car off and restart it.

Tiny
JWard56
Jun 10, 2010.
That car should have a MAP sensor not a MAF sensor. Be sure the connectors are plugged int heright spots, some of those had the same connector for theTPS and the EGR I believe.I would swap your old intake over to the new engine, if it didnt do it before that will eliminate anything other than the engine itself. How much intake vacuum does it have? Does the engine rev up ok or is it slow to accelerate then " catches" up?

Tiny
Jack42
Jun 11, 2010.