Searched but didnt come up with what I was looking for.

My idle on my ZC is going up and down, but only somtimes, it seems like if I baby it, its fine. If I get on it, then stop at a light, it goes up and sits levle for about five seconds then goes down, then back up for five seconds levle, then down again. Also when I hit the defroster button for the rear window, it will start to idle fine. Someone told me this means its the thermomiter for sure. Any truth to this? Any other ideas on what this is? Sounds like a vacume leak, but I dont think it is.........

Thanks for any help

 

I'm having a very similar situation with my 1st Gen B16. It started out just like what you're saying, now it doesn't ever stop going up and down. I posted in here but got only one response. Maybe this post will get some more attention.

 

lol, I dont think so, no response yet. If its not responded to all at once, then no one cares usually.

 

i am having the same problom on my zc. i put it in a few days ago. and when the engine is cold it will idle at like 1500 then when it warms up the idle goes up and down. I am running my pm6 ecu (pg7 was fried) i don't have any codes. How can u tell if the thermastat (sp?) is bad and where is it located on the car?

 

most likely you all have minor vacuum leaks and the ecu is compensating for the leaks by increasing the idle until normal vacuum is acheived.. and then idle goes back down because the computer realizes that the idle is too high for 'normal vacuum' and the process repeats over and over. also when you put load on the motor ie. turning on the defroster, the computer senses a voltage drop and increases idle to spin the alternator faster to compensate.. which will null the vacuum leaks... so dont worry too much.. check your hoes *****aa

 

vacum leak or coolant temp sensor . check ecu 4 codes . Let us know

 

I didnt think eaither of those would give a code? Ill have to go check my hoses better, Any easy way of doing this? And is it the thermostat or coolant temp sensor that would need to be replaced? Like I said, no code for that so I thought it was the thermostat...........


[Modified by ZCcivic91, 3:22 PM 3/16/2003]

 

start your engine.. and spray brake cleaner on your hoses, and fittings, and anywhere that you could have a vacuum leak.. and when you hear the motor change idle.. thats where your leak is.. takes some time but thats the easiest way.. or you could just replace all the hoses

 

should i just check all the hoses that go into and from the intake manifold?
what dose brake cleaner do?

 

check all hoses by the intake manifold , brake booster . And yes i think u can get a code for a coolant temp sensor

 

no CEL here..

 

this site is good..it help me solve my problem
http://www.g2ic.com/forums/showthrea...threadid=42969

 

Could be the TPS sensor on the throttlebody or a minor vacum leak somewhere, double check the rubber lines on the map sensor

 

Good news..

I fixed my problem. It was the FITV. (Fast Idle Thermo Valve) I followed all the things on that link, step by step, until I found my problem. The little white valve things inside was completely unscrewed, so I screwed it back on.

It took me 2 tries because the first time I didn't take my time. I knew it didn't feel like it screwed on, that's because the thermo switch inside has a pretty heavy spring on it, I discovered this upon taking it completely apart.

You've gotta pretty the white thing down inside the valve as much as possible, and hold it while you turn it, if not, it will just turn and not tighten.

This made my idle perfectly smooth now..

That is a VERY good site BTW, thanx for sharing it with us.

 

im glad everything worked out for you, it seems like a lot of us have had that problem, for me, it was the same symptoms, but i had a very minor leak in a vacumn hose. that took forever to find.

 

Ill be looking for my problem tommorow, thanks for the good how to site.

 

ok i am one step closer to fixing my idle.

I read the stuff on that link and on my TB (89 si) it only has one hole befor the throtle plate and when i plug the hole while the engine is running the idle goes back to normal. what dose this mean? i belive that the hole goes to my AICV, but it is new. Is there a way to check the AICV or should i replace it?

 

Never mind! i fixed it!!!! i had some **** on my screen and o ring seals so i just cleaned it off and it is perring like a kitten. i am so pumped!!