Weird Idle, after installing cat~back

[Whitehonda]

Well I installed the new cat~back system a few days ago. No problems except being loud as hell.

I went to go to the gym this morning, and my car was idling at like 2000 rpm, then went down to about 1500 rpm, and then kinda went up/down (back and fourth) between 1000rpm and 1500rpm, quite consistently. Could this have anything to do with the exaust? I have a I/H/E and no cat. I was wondering if anyone had any suggestions on what might cause this weird idle?

Cameron

[BoredRec]

Probably has nothing to due with the bolt-on's. Probbly your cold start valve is wound out too much. It's the thing on the back of the intake manifold, has a brass looking cover with 2 philip screws holding it down. Take off the cover and screw down the cold start valve. That should help the idle problem.

[Whitehonda]

Yeah thanks BoredRec,

I did some looking after I posted my question, then I went and played with the car. I found that unplugging the sensor for the fast idle valve and turning down the idle fixes the problem temporaly, I have to work today, so I am gona have to live with the temp fix until after that.

I did notice that the "check engine" light comes on after unplugging that sensor. Will running ymcar without that sensor hooked up damage anything else? I guess I am confused as to what that valve does.

I do plan on taking it off and cleaning it out later tonight.

Cameron

[shepherd79]

if you unplug the sensor, you will run rich. it is not a problem. it is just a waist of gas on EFI cars.

[Whitehonda]

It seems like quite a few people have had this same problem, does that Cold Start Valve just work itself loose/open over time? It' to dark and cold to work on it tonight, so I am gona do it tomarrow a.m.

Is it worth it to take the whole valve assembly off the intake manifold and clean the shit out of it? I think I might do that tomarrow, and then adjust the idle screw and valve screw. Right now I am running with the sensor unplugged, and the idle screw turned down to about 900 to 1000 rpms.

Thanks Alex, I didn't really understand what that sensor and valve did, It's good to know that I can run fine with it until tomarrow. Any other tips/hints from guys who have done this would be helpful. Thanks again guys

Cameron

[BoredRec]

Yeah, wouldn't hurt to pull the cold start valve off the car and try cleaning the spring inside it (should see if thru the holes on the side where it bolts to the manifold). On rare occasions that spring gets stuck and won't adjust, so it's best just to find a new one, or used one at a junkyard, but definitely try screwing it back down before you do that. Yeah, over time they unscrew, or wear, not sure which...all I know is that at least once a month we get a car in with that problem.

[njpeter]

make that two cars, sounds _exactly_ what is going on with my "new" 86-lx-i..can't wait till the sun comes up so I can have a look see to this cold idle valve. Be simple if the light went on..but this is at least a starting point for my gumout expedition

[Whitehonda]

Hey thanks BoredRec,

This was the exact problem, I did have a hella time taking that cover off. One of the damn screws was in there really tight, and I stripped the head. A screw extractor made quick work of that though, and now I have purtty new stainless screws for it!!!Thanks again!!!

Cameron