Weird idle problem.. voltage related

[Supra-Man18]

Id turn the car on and it would rev up to the normal 1500 rpm for warm up but it would drop very quickly 5-8 seconds... so i hold the rpm at about 1500 as a type of manual warm up.. When i get off the throttle the idle drops straight to 450-500 and wants to die..
***Heres the funny part.. I turn the head lights and fog lights on and then back off.. when it turns off the idle goes up to about 700-750...***

 

[Supra-Man18]

bump up ! want to figure this out !

 

[str8_6]

check the wires going to your alternator on the positive side. sometimes it'll get brittle causing very little connection...giving you that affect. also what is your voltage reading at idle?

 

[Supra-Man18]

Not sure i dont have a volt gauge 8 /.. but im going to check those 2morro and let you know

 

[rj_conerly]

i don't think it would be the alt because its causeing more loading on the engine to maintain the voltage. but i agree check the voltage. if you want to you can read it on both ends of the positive wire going to that alt. i'm thinking its going to be the same. to me it sounds like when you first start it either its not reading the temp kinda like in the summer when its warm out side the warm up is really quick. so maybe the air temp but then again it should still do some kinda warm up. but check connectors and make sure that your not losing any fluids and maybe you need to tweak the idle cause that seems way to low to me. i know in my old rx-7 if i played with the idle screw it would sound like it was gonna die so try that also. other than that check your codes.

 

[Rennat]

my car idles at 650.... when the headlights are on, it idle's about 750-800...

my first thought would be to verify timing at 10 degrees with the connector in the diagnositc port thing

 

[tlo86]

check the wires going to your alternator on the positive side. sometimes it'll get brittle causing very little connection...giving you that affect. also what is your voltage reading at idle?

+1 to this. not enough power is not enough power

 

[Supra-Man18]

I checked everything out.. Ran into sum other probs so had to get those out the way first.. but anyways the cables are in tact, and the so is the positive side of the Alternator... I also cleaned out the IAC valve n connectors.. Still nothing. What next ?