Idle Problems???

[Special K]

What's going on everyone?? Sorry i haven't been on in while!!! But i do have a problem that i can't find an answer to in my cheat manual. Recently it's been cold out and so i would turn my heater on. The heater works fine and makes the engine idle high and then go back down. Which i thought was normal because it's making it work harder. But if i put my heat on as hot as it will go and have the fan on high then it would idle high and then drop really low and studder or conk out. I tried the heater at different levels of hotness with the fan at different speeds and found that if i have the fan on high with the heat any where more than half way up than it'll idle above 1rpm and then drop in between 0-1/4 ways up of an rpm. I'm not sure if it has something to do with the heater, hoses, or what? I can't find no other info on it and i've searched through a ton of threads on here too. I did check my IAC and it's at 11.9V, so it's good. I'm still working on more mods though. Thanks for the help!

[bosscityboy86]

I know wut cha mean, I've been having the exact same problem with mine. I've been searching the forums also and haven't found anything either. I just moved up to Idaho from louisiana last week and it's been really cold up, plus snowing almost everynight since i been it feels like. but i keep the car in a carport.

[SpectorV]

is the car really cold when you crank the heater up?

[Herbstang]

Just a shot in the dark But have you checked for a vacuum leak ????

[bsmith782]

maybe the iacm (idle air control module/motor) i have had to replace mine twice for the same problem, however mine does what your explaining when i have the ac on.

B

[Special K]

Thanks for some help guys!! It doesn't matter if the car's cold or warmed up already. It still wants to die out if i have the fan all the way up with the heat on. I was thinking there could be a leak on one of the vacuum hose seals or something. I'm not really sure but i could try to replace the hoses and or call the dealership...but i didn't want to have them tell me i needed to buy so much stuff or that they didn't know. They don't always know everything. I haven't had the ac on b/c it's been really cold here in Texas lately. We moved here a few months ago from NC and i believe it's warmer there right now. We've had alot of snow and freezing rain here! Hard to believe. Anyways i'll keep searching and if i find something than i'll let ya'll know. But then again i am do for some maintenance.....i just hit 60,000 mi!

[1234]

run better gas the problem goes away like 93 octane or 91 if you dont get 93.
I had the same problem with my 03

[MonteCitan]

Quote: Originally Posted by 1234 run better gas the problem goes away like 93 octane or 91 if you dont get 93

You only need higher octane if your car calls for it, octane has no effect on how the car idles, octane is a measure of how efficiently a fuel burns... higher octane is only used to reduce spark knock in higher compression/boosted applications that are tuned to work with 92/93 octane and want more aggressive timing curves..

Just a FYI

[1234]

not true if you are running a cai your car wont idle right. It idles lower. Then the idle jumps around more if you heat of ac is on. Ive known a couple of people with the same problem and running better gas has stopped it from happening.

[MonteCitan]

Quote: Originally Posted by 1234 not true if you are running a cai your car wont idle right. It idles lower. Then the idle jumps around more if you heat of ac is on. Ive known a couple of people with the same problem and running better gas has stopped it from happening.

I can see this going from citgo gas to sunoco perhaps, but not 89 to 93

[bbunt302]

Going to a higher octane without changing your timing to take advantage of it is a waste of perfectly good money. To help people out who want to spend money on things like this, I have instead set up a trust fund to which they can send their money. The fund will support all of our poor local strippers.

For more information, PM me or something like that.

[1234]

Then explain why better gas solved my problem as well as my buddies

[MonteCitan]

switched to a better station that used more detergents which possibly cleaned up an injector, or whatever... Could be percieved to be better (like the resistor chip on ebay.. add 20 HP! buyers believe it because they expect to feel a difference, mentally they do)

Aside from that.. Octane rating tells you how much FUEL can be compressed before it ignites, if it ignites by something other than the spark plug, it's called detonation, two flame fronts colliding = spark knock = bad for motor

This really only plays a role in higher temperatures/higher loads when something OTHER than the spark plug ignites it (5th gear up a hill under boost, wide open throttle allowing for extra timing advance, etc WOT and high loads = higher cylinder temps = more susceptible to pre ignition) (or if you have something wrong in the cylinder, say a part of a metal head gasket hanging in a bit, or some carbon/etc that gets hot on an edge and ignites the fuel), it will ignite it, the spark plug will ignite it causing the two fronts to collide and again cause knock...

and still it's effect on engine RPMs/ idle quality is slim to none, temperatures aren't typically high enough/ get enough fuel/air for octane rating to matter much at idle. If you use shitty gas with massive amounts of water/other crap in it, it could mess with your 02 sensor readings (or sensors themselves) which could theoretically cause a lean or rich condition to be read... possibly causing the idle to screw up