|
|
|
|
| Author |
|
|
Registered User
Join Date: Feb 2017
Posts: 16
|
Warm idle hunting
Hi all
I have a 2001 carrera 4. My car has a hunting idle(sits at 800 for a few seconds and then drops to maybe 720 for a moment and then goes back up) only when it’s fully warm(at 190 degrees). Anything below that and the idle is perfectly steady. My car also fires up pretty unsteadily when fully warmed up. Ive rules out: MAF, Throttle(clean), and vacuum leaks(idles too well when cold) I suspect: O2 sensors and emissions related components(I’m wondering if there is emissions valves that kick in once up to temp) Not sure: AOS- it would cause equivalent warm and cold issues if it were failing I think Any input? Thanks! |
||
10-23-2018, 08:31 AM
|
|
|
Administrator
Join Date: Aug 2016
Location: Los Angeles, CA
Posts: 6,087
|
Hi Neil - have you tried pulling any codes? This may give you some insight as to where the issue is coming from.
|
||
|
10-23-2018, 12:03 PM
|
|
|
Registered
Join Date: Feb 2011
Posts: 568
|
Not sure if it has one but did you clean the Idle Control Valve?
|
||
|
10-23-2018, 01:41 PM
|
|
|
Registered User
Join Date: Feb 2017
Posts: 16
|
You mean check engine/pending codes? There are none right now. Thanks
|
||
|
10-23-2018, 01:41 PM
|
|
|
Registered User
Join Date: Feb 2017
Posts: 16
|
No idle control valve on my car
|
||
|
10-23-2018, 01:42 PM
|
|
|
unindicted co-conspirator
Join Date: Jul 2007
Location: Fresno, CA
Posts: 1,660
|
there is a check valve from the secondary air injection that gets crudded up and will cause a warm idle fluctuation, especially when coming off of the freeway to a red light
PITA to get to, have to remove the alternator
__________________
'03 996 - sport exhaust, sport seats, M030 sport suspension, stability control, IMS Solution ‘86 928S3 - barn find project car |
||
|
10-24-2018, 03:09 PM
|
|
|
|
Of the Moby Gang
Join Date: Apr 2013
Location: USofA
Posts: 132
|
From the 996 tech articles:
"One poor-man's way to check for vacuum leaks is to artificially create a leak and see how the engine reacts. There are two primary vacuum systems on the Carrera engine--crankcase vacuum and intake manifold vacuum. You can test for proper crankcase vacuum by removing the oil cap while the car is idling. The engine should change idle and begin to run a bit rougher with the oil cap off. If there is no change in the running of the engine, then you might have a crankcase vacuum leak somewhere (sometimes caused by a failing air-oil separator--see Pelican Technical Article: Porsche 911 Air Oil Separator). To induce a vacuum leak into the intake manifold, you can disconnect one or more of the hoses that connect to the intake. One example would be the hose that connects to the air-oil separator. If you crack one of these hoses open just a bit and the engine rpm doesn't change, then you might have an intake vacuum leak somewhere." |
||
|
10-25-2018, 08:49 AM
|
|
