Crazy Idle Surge Concerned engine my Grenade itself
 

I was changing the timing belt on my D16y8. After putting it back together, I started the car and the rpms just shot into the redline. The rpms never let up! At first I thought I'd pinched the throttle cable, but everything looks fine. I disconnected the vacuum hose from the intake manifold to the throttle body and that dropped the rpms to the 5500-6000 range. I know that's not a fix, but it's better then seeing your baby race into oblivion. I read that air in the coolant can cause idle surge, but is this extreme "normal"? The engine seems to be under so much pressure. Thanks.

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

Is the CEL ON?

Is the throttle plate stuck open?

You definitely want to bleed the cooling system of air as described in the service manual.

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

So is this kind of idle surge normal for air in the coolant? The CEL wasn't coming on until I disconnected the IACV. Now the CEL stays on. The throttle didn't appear open. I made the mistake of stepping on the throttle and she still wanted to rev. I'll look at the plates tomorrow.

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

Trapped air in the cooling system can discombobulate the ECU due to incorrect signals sent from the coolant temperature sensor and incorrect temperature readings by the IACV.

Here how to retrieve the CEL code(s) from the ECU:

http://honda-tech.com/zerothread/1901557

When codes are retrieved, clear the ECU and determine whether the same codes are thrown again. Troubleshoot any repeated codes.

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

Thanks RonJ will do tomorrow after work. I'll keep you posted. Thanks again!

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

Okay, I disconnected the tps to see if my idle would slow down,the CEL came on and you guess it it pulled a P0122 throttle position circuit low input. I'm figuring this code was cause by my disconnecting the tps. I'm goingto clear the code on Saturday to seeif pops againand try the antifreeze fix. A question for you veterans... is there a release valve on the lowside radiator hose? I can't seem to find it. I keep reading that there is some release valve that helps bleed air from the system. Any pics would be really helpful. Thanks again for helping the Noob!

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

The D16Y8 engine does not have a bleed valve. Search the forum for the downloadable 96-00 Civic service manual. It describes the proper bleeding procedure for the cooling system.

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

yes like Ron said, you need to bleed your coolant system, it seems like it has air in it. Good Luck


Btw Ron, are you a mechanic? and why is yoru PM disabled?

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

Thanks RonJ. I was looking at the manual, how critical is the removal of the antifreeze bolt by the oil filter? In the manual the bolt is to be removed, but on the forums not everyone seems to remove it when bleeding the antifreeze.

RE: Crazy Idle Surge Concerned engine my Grenade itself
 

Im pretty sure he is, he has helped so many people and he always knows exactly whats the problem.