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Driving member
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Finally...problem solved, hesitation etc
Well I hope that I am not posting here too early. I thought I had this problem solved several times. I know a lot of you guys have had similar problems.
Symptoms... Hesitation, surging and stalling or almost stalling. Mine did this mainly going from idle/dead stop as I gave it gas to pull away. Sometimes at a slow speed would also do it in 2nd gear but mostly in first. It sounded like a vacuum leak. As I would step on the gas the car would suck air and then almost stall. You could definitely hear the air sucking sound. After having the engine out for a clutch replacement among other things, I replaced most of the vacuum hoses. They were 20 years old anyway. So no loss. Anyway with out making it too much longer the symptoms came back. Finally out of desperation I removed the afm and opened it up. I bent the potentiometer needle inward to get it off the old track and put a spot of dielectic grease on it for better contact. BY GEORGE I THINK I FIXED IT!!! Here is a pic from a 944 afm that shows the same needle. Just posting this for others that may have the same problem. Your results may very  
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Jerry '86 coupe gone but not forgotten Unlike women, a race car is an inanimate object. Therefore it must, eventually, respond to reason. |
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03-25-2006, 04:31 AM
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Registered
Join Date: Dec 1999
Location: Novato, CA
Posts: 4,740
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Congartulations.
But be careful with the dielectric grease. It's mainly used for it's insulating (dielectric) properties and not intended to improve conductivity. Cheers, Joe |
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03-26-2006, 06:49 AM
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Registered
Join Date: May 2000
Location: Los Alamos, NM, USA
Posts: 6,044
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In this application dielectric grease is not for insulating, it is to keep an electrical contact area free of corrosion. If there is sufficient needle pressure to "wipe" the contact, the grease will help not harm.
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03-26-2006, 07:11 AM
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RETIRED
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The Throttle Positioning Switch by any other name is always a PITA to diagnose....once fixed you keep smacking yerself in the head....
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1983/3.6, backdate to long hood 2012 ML350 3.0 Turbo Diesel |
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03-26-2006, 07:17 AM
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Driving member
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Thanks guys. It has been a real head scratcher for over a year. I hate to just throw parts at something until it is fixed.
So I have been trying to find it through diagnosis. Does anyone know where one might get the afm rebuilt? At some point this will wear down as well. I don't really want to pay the price for a new one if the one I have can be rebuilt.
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Jerry '86 coupe gone but not forgotten Unlike women, a race car is an inanimate object. Therefore it must, eventually, respond to reason. |
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03-26-2006, 08:58 AM
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Registered
Join Date: Dec 1999
Location: Novato, CA
Posts: 4,740
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"In this application dielectric grease is not for insulating, it is to keep an electrical contact area free of corrosion."
Contact cleaner? |
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03-26-2006, 10:57 AM
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Driving member
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The problem is the needle or vane rubs on the same arc over and over cutting a groove in the contact surface. What would be ideal is to have this area resurfaced.
The other parts don't really need to be replaced. At least not yet The grease helps to: A. Not cut a groove as much, and B. Keep an electrical contact. These parts are now over 20 years old so it is understandable. In the picture you can see 2 small grooves in the little black arc/contact surface.
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Jerry '86 coupe gone but not forgotten Unlike women, a race car is an inanimate object. Therefore it must, eventually, respond to reason. |
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03-26-2006, 11:20 AM
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1986 Porsche carrera coupe 3.2
Da cab
