2.2L

I just put in a new head gasket and got things pretty much back together.

I turned the car over and it "idles" up to 5000 rpms, settles down to around 1500, then surges back up to 5000.

All vacuum hoses are on where they belong, all electrical is hooked back up.

I have not seen similar symptoms in other places in this forum. If I have missed something please feel free to direct me to the proper thread.

The intake manifold had some crud in it which I sprayed with some cleaner when it was off the block. Did I maybe gum up a sensor or something up inside there?

Thanks for any leads you can provide.

I used the propane test to check for vacuum leaks and nothing changed. I removed the intake hose from the air filter and the throttle plate remains closed while it does this revving. I "cleaned" the IACV (the screen was full of crud) but no change. There are no Check Engine lights unless I remove a sensor.

I am tempted to do a 180 on the distributor, but if I do that I expect the car won't even start.

 

Have you removed any air pockets from the cooling system? That seems to confuse Honda's idle-control system.

There's a bleed valve at the thermostat housing where air seems to accumulate. Between that and the radiator cap, and open the heater to full-hot to get air out of the heater core.

Any vacuum leaks?

There's 2 different intake manifolds. What model/trim is your car? Does it have the IAB valves in the manifold?

1993 also has that air-boost valve at the far end of the intake manifold. I bet Poorman has some experience setting up those things.

 

Hey, Jim! Thanks so much for the reply!

I have a funnel mounted on the radiator top and I have been continuously bleeding the system throughout this mess. As I added in the original post I have checked for vacuum leaks—and I forgot about opening the heater valve until this morning, but that was done and there has been no change to the surging.

My Accord is an SE. You have me stumped on IAB valves...I'll go look as soon as I post this. I have seen a couple of YouTube videos on the air-boost valve. Should I block that off?

 

Is IAB the same as IACV?

Here's a picture of my setup:


MORE NOTES:

I took off the air boost and put my fingers over the holes. With my fingers on it the surging is the same. When I take off my fingers the RPMs go even higher. I have spun the disk on the FIT down to the bottom. Maybe I should pull the IACV/IAB and see if I can get the current pattern to change. Twice I have taken off the battery cable to reset the ECM.

I've gotta think this has something to do with the intake...it just acts like there's a little man stomping up and down on the accelerator.

Otherwise, I have run out of ideas on how to lock down this surging.

 

I gave up and scrapped the car.

 

Wow, hope you got some of your money back out of it....

 

Ouch! I go out of town for a few days & people start throwing away their cars.