Help!! my engine revs up and down at high rpms
 

hey there
i just bought a 96 accord 25th anniversary edition. the car has a rebuilt motor in june of 2008 so i know it cant be the motor. but reccently i have been having a problem that after i drive it the engine starts to rev up and down after i park it.when i start the car up it idles at 1200-1400 rpms and when i put it in park or neutral it goes up to like 1900 and starts going up and down between 900-2100. i was told it could be my iacv. i also have a radiator problem where my overflow tank is completely empty even after i fill it up. does anybody have any ideas on what it could be??:crook:

and no i dont have a radiator leak because i have a brick driveway and i would have seen it on the floor with all this cold weather and dry brick.

Re: Help!! my engine revs up and down at high rpms
 

Well it could be you ICV witch you can take apart and clean the screen or take a can of brake cleaner and spray it where your intake bolts to the motor and see if it clears it up for a second and if it does your going to need a new intake gasket. As for the anti-freeze check your oil and make sure it looks good and dont look like its mixed with something also check your anti freeze and make sure theres no oil in it cause you could have a blown headgasket or a crack in your radiator thats only leaking while driving! hope this helps man

Re: Help!! my engine revs up and down at high rpms
 

You're low on coolant.

Remove the cap from the radiator and fill it. The overflow bottle is just that, an overflow. You don't use it to fill the cooling system.

Fill the radiator and bleed the cooling system for a bit. The idle fluctuation should stop.

Messing with the IACV is not going to do anything at this point, because it isn't receiving enough coolant supply to work properly.

You may want to have the cooling system pressure tested for a leak.

Why was the engine rebuilt?

Re: Help!! my engine revs up and down at high rpms
 

that actually sounds like a pretty good idea..lol i will try that first thing this weekend ..i will fill it and then fill the overflow tank too.. and follow the rest of your steps and get back to you asap..thank you alot

and i have no idea why the rebuild was applied.. my bro took a ride in it before it got rebuilt and it was good i was told.. it was my bros friend that i bought the car from. but her put high compression pistons or something like that..

the car drives really nice ..its just that idling issue i have and i dont think i can pass my up coming inspection with the engine revving up and down can i??

Re: Help!! my engine revs up and down at high rpms
 

I had recently the same issue with my 91 accord.
I bought it like that and thought it was a matter of cleaning the screen. When I pulled the iacv out, the screen was dirty, but the coolant passages of the IAC and Fast Idle Valve, were 100% clogged up.

Now about the coolant issue, check your muffler. If they had to rebuild the engine because it overheated, you might have a water leak into one of the exhaust valves; from either a blown head gasket or a cracked head.