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Registered
Join Date: Dec 2005
Location: Riverside, CA
Posts: 463
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What's up with my idle?
Hey guys,
Sometimes...yes...sometimes, my idle is hunting... Usually, the car starts up great and idles perfect (after about 5 seconds), but sometimes lately, the idle hunts up and down (1200-700-1200, etc) for about 15 sec or until I step on the gas a bit. After that, never a problem. What could this be? I'm planning on refreshing the complete fuel system and vacuum lines, so hopefully that cures it. Any ideas?
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Horsepower is how fast you hit the wall...Torque is how far you take the wall with you... 1994 BMW 325is M-Technic 1986 Porsche 944 N/A |
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12-11-2007, 11:36 PM
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Registered
Join Date: Sep 2002
Location: Barcelona
Posts: 136
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It sounds to me like your idle stabilizer valve is gunked up. It's located underneath the intake manifold, but can come out with some manual contortion if your fingers are not too big.
Pull it out and give it a good cleaning with WD-40 or some solvent. Make sure it's dry before you reinstall it and see if that improves any. |
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12-12-2007, 01:54 AM
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Let's go shooting.
Join Date: Feb 2003
Location: United Kingdom.
Posts: 1,200
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You could also try cleaning up your engine grounds. There's a quick test for this - start the engine up and then clamp a booster cable to the engine and a decent ground or to the earth (ground) terminal of the battery (if it's mounted in the front). If the idle improves then you know you need to clean up your strap points.
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1983 944 Lux (manual) 2.5 litre 8 valve na and no pas 1991 944 (automatic) 2.7 litre 16 valve na and pas "I have only five words for you: From my cold, dead hands." |
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12-12-2007, 02:05 PM
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Registered
Join Date: Jun 2003
Location: Fresno, CA
Posts: 7,769
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Quote:
I noticed that my ground point is corroded (a little) on the engine block and my idle gets erratic when I turn on the rear window defroster - I've been planning on cleaning up that ground point when I replace the vacuum hoses under the manifold (soon). But, I'm going to try your suggestion just for kicks - it certainly couldn't hurt. Vern |
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12-12-2007, 03:24 PM
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unindicted co-conspirator
Join Date: Jul 2007
Location: Fresno, CA
Posts: 1,660
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I installed a Wilk PP2 2 weeks ago & now when the motor is cold, the idle hunts for about 2 or 3 mins. until warmed up.
I know that the chip ignores the O2 sensor, & that was probably hiding whatever problem was making the cold idle hunt is there any easier way to clean the ISV than taking off the intake manifold to remove the ISV?
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'03 996 - sport exhaust, sport seats, M030 sport suspension, stability control, IMS Solution ‘86 928S3 - barn find project car |
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12-12-2007, 03:43 PM
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Registered
Join Date: Sep 2002
Location: Barcelona
Posts: 136
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You can remove the ISV without pulling the intake manifold. It's a bit@#, but it can be done unless you have large hands.
Thanks for the tip, Dark Skies. |
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12-12-2007, 11:43 PM
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Join Date: Jul 2007
Posts: 79
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My idle did that so I ran some carb cleaner through it...lots of smoke but cleared it up after a few smokey minutes.
Otherwise, you have a vacuum leak or a bad ground as stated.
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Rick, Chatsworth, Ontario, Canada 1988 944S 18" 993TT wheels Magnaflow hi performance exhaust K & N air filter and MaxHP Kit chip |
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12-13-2007, 06:09 AM
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Registered
Join Date: Dec 2005
Location: Riverside, CA
Posts: 463
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Thanks guys for all the tips. I'll get busy with it and start checking the ISV first.
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Horsepower is how fast you hit the wall...Torque is how far you take the wall with you... 1994 BMW 325is M-Technic 1986 Porsche 944 N/A |
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12-13-2007, 08:23 PM
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Mein Gott!
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Quote:
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Johnny 1987 944S 1984 944 (R.I.P.) 1972 Triumph TR6 - 100% trouble free between breakdowns 2003 BMW 325xi |
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12-14-2007, 05:30 PM
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Registered
Join Date: Sep 2002
Location: Barcelona
Posts: 136
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Quote:
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12-14-2007, 11:02 PM
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What would Darth Vader do
Join Date: Feb 2001
Location: Orange, California
Posts: 1,324
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Here in California, to cut down on emissions, the fuel suppliers at state regulation will re blend the gas with ethanol during the winter. To get better firing and cleaning out the left over deposits, you need to run a few tanks of Chevron fuel or a bottle of "Techron?" to your fuel occasionally. Other states may do the same but I am not aware.
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1983 944 (2002 to now) 3-924's (Sold) 1967-912 (Traded) NEVER put a used water pump in your car... |
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12-15-2007, 01:51 PM
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Registered
Join Date: Dec 2005
Location: Riverside, CA
Posts: 463
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Hmmm...that might not be a bad iea.
Also, I have the feeling that when it's parked with its nose down, it fires right up, but when parked nose up, it cranks about 5 times...Does that give anybody any clues?
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Horsepower is how fast you hit the wall...Torque is how far you take the wall with you... 1994 BMW 325is M-Technic 1986 Porsche 944 N/A |
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12-15-2007, 04:49 PM
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What would Darth Vader do
Join Date: Feb 2001
Location: Orange, California
Posts: 1,324
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I'd try the Techron first. And then see if for some reason your fuel pump pressure is light if the techron doesnt work. I think you'll see a vast improvement if you switch to Chevron though (Or the techron additive)
Quote:
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1983 944 (2002 to now) 3-924's (Sold) 1967-912 (Traded) NEVER put a used water pump in your car... |
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12-15-2007, 08:02 PM
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