Average Idle Speed

**TransAm11973** · 08-29-2009, 10:32 AM

Whats your guys average idle speed, working on adjusting my TB. I have a stock cam......and go!

**TransAm11973** · 08-29-2009, 03:54 PM

no one??? I guess you guys dont have working engines....mine was around 500rpm's and I raised it to about 750rpm's seems to be running better. Tomorrow I will hook it up to obdII to get the exact rpm's

**2001NBMZ28** · 08-29-2009, 04:08 PM

Guessing A4? Open loop or closed loop? In gear foot on the brake or Park/Neutral? Before tuning mine was 646-676 P/N, 525-585 in gear on a scanner.

**TransAm11973** · 08-29-2009, 04:17 PM

A4, closed, park

**pajeff02** · 08-29-2009, 05:58 PM

I want to say it is right around 580-ish in park. I just remember thinking it has kind of a low idle rpm after we bought it. Will try to check it with my scanner tomorrow.

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Just checked it with my scanner about an hour ago. Engine warm, in park, A/C off, cooling fan running and it was 630-650.

**Firebirdjones** · 08-31-2009, 06:52 AM

I bumped mine up in the tune on both cars. Didn't like how low they idled. One's an auto and the other a manual.

I have the auto idle about 650 in gear with AC on and off,,, and 750 in park.

I have the manual idle at 800 because it has a smallish cam, and I wanted to smooth it out a bit. But it idles down to 600 if you want it to.

**rbob93** · 08-31-2009, 07:08 AM

As per the stock tach, a4, in d, foot on brake = between 500 to 550

**Frost** · 08-31-2009, 11:20 AM

A few things about this thread....

1. Your stock tach is not accurate, so if you are going by that, you are ill-advised, you must use a scan tool.
2. You can't raise the idle with a set screw, the PCM fights for what it is programmed to idle at. If you jack it open far enough, your TPS will not read 0% which will cause an issue.
3. If you actually GET a raised idle, you will get a code and you are causing issues that are not apparent to you now. A side is that your IAC is now fully closed as it fights against the extra air you are letting in. On a hot day, your idle will idle wander higher and want to hang, especially with the car moving.
4. Your extra un-accounted for airflow will make the car 'push' when it is moving.

**pajeff02** · 08-31-2009, 11:22 AM

Originally Posted by Frost

A few things about this thread....

1. Your stock tach is not accurate, so if you are going by that, you are ill-advised, you must use a scan tool.
2. You can't raise the idle with a set screw, the PCM fights for what it is programmed to idle at. If you jack it open far enough, your TPS will not read 0% which will cause an issue.
3. If you actually GET a raised idle, you will get a code and you are causing issues that are not apparent to you now. A side is that your IAC is now fully closed as it fights against the extra air you are letting in. On a hot day, your idle will idle wander higher and want to hang, especially with the car moving.
4. Your extra un-accounted for airflow will make the car 'push' when it is moving.

Out of curiosity, what should stock idle be on an A4 equipped car?

**Frost** · 08-31-2009, 11:28 AM

It's very low, at full temp it's 650 in P/N and 550 in gear.

**TransAm11973** · 08-31-2009, 02:41 PM

Originally Posted by Frost

It's very low, at full temp it's 650 in P/N and 550 in gear.

frost after I installed my ported TB, my car seemed to be idling too low, it just didnt sounds right.....So I adjusted the screw on the TB, now it idles around 750 and in gear around 550 to 600. It seems to run better now. Do you think this is ok. I still havent hooked it up to my scanner. Being lazy may do it later

**TransAm11973** · 09-02-2009, 05:17 PM

frost?

**Frost** · 09-02-2009, 07:39 PM

Originally Posted by TransAm11973

frost after I installed my ported TB, my car seemed to be idling too low, it just didnt sounds right.....So I adjusted the screw on the TB, now it idles around 750 and in gear around 550 to 600. It seems to run better now. Do you think this is ok. I still havent hooked it up to my scanner. Being lazy may do it later

You want to log IAC counts. Stock cars have more lee way, but look to adjust for 65-85 counts at hot idle. This is the proper way to setup a TB.