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Registered
Join Date: Sep 2005
Location: Utah
Posts: 100
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85 Rough Idle
I'm not really sure whats goin on. but if you start her up and let her sit you can sit and watch the idle bounce between about 1500 and 300 and sometimes it sounds like it is going to die. I am getting ready to do a tune up on it as a first atempt to fix it but is there something that I'm not aware of that i should check for idle stability???
85 911 Carrera |
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12-11-2006, 08:56 AM
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Join Date: Oct 2005
Location: Birthplace of Bix
Posts: 1,145
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Check for a loose vacuum hose(s) first...
Could also be a bad sensor, DME/chip. You might have to hook it up to a diagnostic analyzer or go through the Bentley troubleshooting checklists. Good Luck! Regards, BTW, my 85 Carrera idles a little rough, too, but not the extreme case you describe.
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Joe 85 Carrera 64 Honda Dream - for sale 71 Hodaka Super Rat - keeper |
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12-11-2006, 12:33 PM
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1985 Carrera Coupe
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Jbagel2,
Did you fix this problem? What was the source? Did you try replacing the intake manifold gaskets?
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Art |
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08-18-2007, 04:56 AM
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Location: Utah
Posts: 100
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No i have not fixed the problem, no i have not replaced the intake manifold gasket. but i have checked for leaks. i have checked the idle control valve and it seems to pulsate open and closed, but i'm not sure if that is normal. or if it should just be open if its "Open" and be closed if it "Closed".
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08-18-2007, 10:50 AM
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Member 911 Anonymous
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I replaced my DME relay and it worked great for a week or so then the hunting came back once and rough idle when cold start. But driving is perfect except when cold and at stop, rough idle.
I am planning a CHTS replacement. I have the older single wire so I am hoping this will fix it. I did drive her in really hot temperatures previous to the DME relay replacement. I read the CHTS will burn out and especially if it is the single wire so that is my next labor of love.
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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10-01-2007, 05:08 PM
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1985 Carrera Coupe
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DRACO,
CHTS = cylinder head temperature sensor???
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Art |
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10-02-2007, 04:52 PM
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Join Date: Jul 2002
Location: Southern California
Posts: 5,067
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Have the mixture checked.
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1984 Targa |
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10-02-2007, 05:13 PM
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Member 911 Anonymous
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Quote:
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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10-02-2007, 06:02 PM
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Join Date: Sep 2005
Location: Utah
Posts: 100
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So did that fix it?
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10-04-2007, 10:34 AM
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Registered
Join Date: Aug 2006
Location: Albany, NY
Posts: 155
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Try spraying some parts cleaner in ICV. Cleaning it could help. I cleaned mine and it was better for about a month and now the idle is bouncing pretty hard again. I just ordered a replacement from our host. I was told the valve can be come lazy when it gets old.
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1987 911 Carrera 2006 Audi A3 |
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10-04-2007, 03:32 PM
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I've got an '83, so may be slightly different, but had similar problem.
Mine used to cycle badly on cold start up, until warm. It was too rich and loading up - which drops the revs, and almost dies on gear changes. Once it was tuned right the problem went away. So, it could be rich mixture, or WUR faulty, or not enough auxilary air on warm up - if your system has Aux air valve. Alan |
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10-04-2007, 08:14 PM
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Member 911 Anonymous
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Quote:
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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10-11-2007, 12:00 AM
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Member 911 Anonymous
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Update:
It was my Idle Control Valve I did the ghetto check and tapped the ICV with the but of a screw driver when it hunted and it went away. Metered it, center registered proper OHMs but the two outer connections did not register proper OHMs. Bought a new ICV at Autozone for $124, yes $124. I was surprised. I was skeptical it was manufactured by Wells/Duralast. When I opened the package it had a Bosch Label on it and "00" stamped at the inlet/outlet housing. My old one had "84". I metered it at the store and registered perfectly. It must be a re-furbished unit but the manuracturer warrants it for 1 year, Autozone for 30days replacement guarantee. (Sorry host) Installed it in 10 minutes, checked for leaks using ether, no leaks. Started my baby cold. To my pleasant surprise, it idled at 1200 RPMs then about 30 seconds later idled down smoothly to 800 RPMs, exactly the way it is supposed to work. No more rough idle or hunting. Going Good for a week now. Problem Symptoms History: It never cold idled at 1200 RPMs when I bought it, always 800 RPMs, hunted occasionally (thought it was old car characteristics, duh) Alternator Died Jumped Started Alternator Replaced Extreme hot weather driving, heard buzzing (AAV, found out later, pending replacement) While warming she died Replaced DME Relay 2 weeks later rough idle and more hunting Improperly replaced new CHTS (did not tighten on to cylinder head #3 and twisted the wires, did not have the special tool) Properly re-installed CHTS (with modded 4" deep socket) and new DME Relay (1st replacement burned out due to improper installation of CHTS) Still rough idle and Hunting Checked for air leak at manifold using ether, no leak present Took off ICV and cleaned the heck out it & light lube Hunting at cold start now (doh) Replaced ICV, Problem Solved and added 1200 RPM warm up, no more hunting and quick starts and acceleration. 
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC Last edited by DRACO A5OG; 11-10-2007 at 01:20 AM.. |
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11-10-2007, 01:16 AM
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Marble Grey
