High Idle

[ramell86]

Alight, heres the deal.

My 89 Galant GS DOHC idles fine once shes warmed up, but it seems to take forever for it to happen. We are talking probably longer than a few minutes with the car idleing sometimes higher than 1500 and then it gradually decreases to normal level.

Is this alright considering its winter and pretty cold outside?

Thanks for the help.

[seth98esT]

Yah pretty normal with older cars. Let me guess, it only does it around 15F and lower temperatures? Back when it was 5F my 90 Talon TSI idled at 2k untill it warmed up and then dropped to its normal 900. The weight of your oil should play a part in it too. In winter weather you should use a lighter oil like 5w-30...

[Edit]
BTW I am using 10w30 in the Talon. Just changed the oil before winter in Nov and should have used 5w30 arg

[ramell86]

actually it seems to do that above 15f.
But I guess theres not much you can do with an older car.

I didn't know about using a lighter oil, you should have told me when i changed it a month or so ago lol

[3diamonds]

There can be a number of possible problems:

1. FIAV-fas idle air valve, inside your throttle body there is a thermostat-like device, which is open when its cold, and closes when coolant warms up, basically it lets more air in when the cair is warming up...hence the coolant lines comming into the TB, they go bad after a while, or IF YOU DISCONNECTED cooling lines they obviously get stuck in open.

2. ISC-idle speed contrloller (motor) it is also on your throttle body, and with a 12 year old car it can AND DOES fail, most of the time intermittenly, so it works sometimes, sometimes it doesn't, get a used one off ebay for 40$ iuf yours doesnt work.

3. BISS-base idle speed screw, this regulates the idle maually, there is a orange looking plastic screw on your throttle body that you can twist with screwdriver that will adjust idle, NOTE:YOU MUST GROUND the IDLE WIRE in order to set timing OTHERWISE THE COMPUTER WILL TRY TO COMPENSATE.

4. Have you changed the capacitors on your ECU (comp) after a while they tend to leak and cause some really wierd things, take your ECU out and check it, it is behind radio.

5. Boost leak..if you have turbo.

6. Mass airflow meter dying, the big thing connected to airfilter and airhose, that measures the karman vortex (basiacally generates a frequency between 100 and 1600 hz, whuch your ECU uses to calculate the amount of air comming into the system.

7. Sensors, make sure all connectors are plugged in and that all sensors are grounded and working.

8. Timing!! check your base timing, go to a mechanic if you cant do it, it should be 5 degrees BTDC.

[ramell86]

could someone help me locate the Idle control valve in relation to the throttle body. I can't seem to find it.

I believe this is what is causing the weird idle, so any help could be appreciated.

Thanks