Well, my car has done this for some time now. I noticed that it seemed to get a little better when i changed out my spark plugs for new ones. But it still happens.
Basically, when im cruising in a certain gear, and the rpms are anywhere above 2000. I can take my foot off the clutch and the rpms will drop, but it wont catch its idle. Now, ive gotten used to just tapping the gas pedal a tiny bit as the rpms are dropping to assist it in catching the falling idle. This seems to work okay, but doesnt seem like i should have to do that. My car idles fine once the rpms are caught, and it idles fine when i first start the car. Only a problem catching a falling idle.
It doesnt seem like a vacuum leak to me. Ive got a 94gsr head, and skunk2 IM, with gsr throttle body, with a clutchmasters lightweight flywheel. My current idle is set at about 820rpms. I am also using a 98 crv IACV.
I was thinking that possibly it was the iacv that i am using? Maybe it needs to be cleaned? Maybe i need to get a gsr or typeR iacv? Maybe i need to adjust my idle even higher? Maybe the problem is related to running too rich at idle(im using 310cc injectors)? Maybe this is a normal thing with a lightened flywheel? Any ideas on what to try? Maybe i just need to not worry about it and be happy that my car is haulin ***.

thanks very much

ERIK

 

my "race" LS did this too, when I rebuilt it and "souped up" the head. seems to definitely be related to running too rich; when I backed off the fuel press a little and tuned with the Fields it no longer does this.

I have a fairly mild set of Webb cams in it; idles between 700 and 800 rpm, slightly lopey.

I bet u are running really rich at or near idle.

later,
Todd
#11 H1 Honda Civic DX-LS

 

It's the over rich condition at idle, our setups are very similar, I thought it was a trade off of the light flywheel too, but its not. What is your tps voltage at closed throttle? Check this first, if it's not below the .5v, ecu won't cut fuel on decel, and it'll want to stall coming to a stop. What is you idle fuel pressure w/vac? Try dropping fuel pressure first, then add more air. If the tb adj. screw is backed all the way out, you could use the throttle stop screw to open the blade slightly. Of course you could always just buy a controller, but what fun would that be?

Did you ever figure out what was up with your catchcan filling so quickly?

 

Great, thanks for the replys. Ill let you know 2morrow what my tps voltage is. My fuel pressure at idle with my gsr stock ecu, rc 310cc injectors, is about 27psid at idle with vac. I do have an apex vafc, but havent played with it too much yet, because i have yet to take it to the dyno.

As far as my catchcan setup goes. No, i dont know why it filled up so fast. But it is working fine now. Im using a filter on top instead of the pcv. And it drains back into the block. Just like endyns setup. Thanks for askin!! good memory.

ERIK

Oh yeah, any tips on how to tune my car with my vafc to help my catching idle problem?

 

Drop the idle pressure to 25psi and drive it. If it still does it, reset the idle a lil higher, try again. You could also try pulling some fuel out on the vafc at 0-1000rpms.

 

I checked today, and my tps voltage at idle/closed throttle is sitting right about .52-.53volts. Could that be the problem that you were describing earlier regarding the fuel not cutting off on decel? I will try lowering fuel pressure like you suggested, and re-tuning the vafc.

ERIK

 

Check the screws on the tps, if there is no slot, make one with a dremel. You'll probably have to remove the throttle body to make it easier. Once you loosen them you can adjust the tps voltage by rotating the sensor. Do it with the voltmeter hooked up, key in the on position, engine off, adj to liking.