i drive a 99 civic coupe with a 99 gsr swap. everything is stock cept lsd clutch flywheel which probably has nothing to do with the idling. im out here in il and it gets pretty cold out here. when its cold out, and im driving on the highway, my temp guage is at the C line. seems kinda too cold for a motor thats been running on the highway for 30 min? or is that normal? it does up a 1/4 of the way if i dont turn on the heat, but once i do, it goes back down to c. when im at a stop and its cold out, it gets somewhat near the middle of the guage...as long as im not driving around. recently, my speedo went out and i think its cause the vss sensor cause sometimes it works and sometimes it doesnt. but besides that, i installed my 99 gsr ecu not too long ago cause ive been running an si ecu. after driving on the highway for about half an hour and i come to a stop, my idle goes up and dowm from 1.5 to 2g. it goes up to 2 then back down to 1.5 then up to 2 again. the weird thing is when i turn off my car while its doing that, then turn it back on, it idles fine at around 7-8. what would make the idle jump around like that? i dunno if this all sounds confusing... if you guys have specific ?'s ill be glad to answer.

 

My Ls/vtec used to do that all the time- and it was my thermostat!

 

which part? the idling or the temp

 

up

 

The thermostat could be missing it's spring and allowing your radiator to be fully open all the time. I think that is it your temp sending unit myself. The little one wire sensor on the side of the head. You can check the circuit by taking off that sensor and connecting a jumper wire to your battery ground. Then turn the key to the on position and your temp guage should go to full hot. If this happens then your circuit is fine and you can replace that sensor(screws right out) for 13 bucks. My temp guage didn't move at all after rewiring and that sensor was the problem. No honda should be running at 0 temp after 30 minutes of idling or driving. However, this will have nothing to do with your idle problem. Believe me, I know.

 

nice thanks for the info..ill check it out. where can i get the sensor at?. my car heats fine when its just sitting there without movement.

 

the wierd thing is, is that when im at a stop in the parking lot or something, my car temp goes towards the middle and stays there until i start to drive again. and when i start driving, the temp need just goes down and even past the 0 line when its real cold out. that just seems reallly wierd and unhealthy for the car. someone help me out!

 

bump for some suggestions as to whats goin on with the temp of my car!

 

Replace that thermostat, its cheap and easy. Regulates your coolant temperature!!

 

thats whats cause my motor to get cold while driving? and warm up a little while im stopped in a parking lot?