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Registered
Join Date: Nov 2008
Location: La Grange, GA
Posts: 5
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Air flow meter isn't working
Hello guys,
I had posted last week about a broken timing belt. Got it all back together and it won't idle. Traced it down to the air flow meter not working. Connected electrically and to the j boot, just not working. Engine sounds great besides this small but major problem. Any thoughts on troubleshooting this? Have a great Thankgiving!! 1987 944 NA 
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11-27-2008, 10:53 AM
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Redline Racer
Join Date: Jan 2007
Posts: 2,444
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What do you mean by not working? If the AFM is flat out not working, then the car wouldn't run, or would only barely run. Do you get voltage from the DME at the connector? Should be 5v for your car. When you check it, you must check it against the ground wire in the connector. Checking it against the nearest metal part on the car will not work.
This should help. It's got all the pinouts, test procedures, specs, etc. http://www.frwilk.com/944dme/afm.htm I also made a video of adjusting the wiper arm. Just search youtube for "Bosch motronic air flow meter" If there's still problems, you'll have to check that the actual wiring between the DME and the AFM isn't broken/shorted out. For testing the AFM response, my favorite way is to test it at the DME connector itself. That way, you simultaneously end up checking the wiring, too. Just take the DME connector's protective cover off the back so you can access the pins in the connector with meter test leads while the connector is still plugged into the DME. Then just turn the key on and move the flap. You should see a steady linear increase from a couple hundred millivolts to about 4.5-5v. Here's the DME pinout. http://www.frwilk.com/944dme/connector.htm You'll want to test between pins 6 and 7.
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1987 silver 924S made it to 225k mi! Sent to the big garage in the sky Last edited by HondaDustR; 11-27-2008 at 05:03 PM.. |
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11-27-2008, 04:51 PM
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Clarkes garage has a nice proceedure for checking and cleaning the AFM. I've used it and it does work.
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'86 944 Turbo You have to be a masochist to love something so frustrating. |
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11-27-2008, 05:34 PM
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Registered
Join Date: Nov 2008
Location: La Grange, GA
Posts: 5
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I understand how it works now. I think I have a vacuum leak near the rear of the head by the firewall. I'll have to find out what's back there. Does that sound correct? Low vacuum so the flap isn't moving unless the rpm is near 4000.
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11-28-2008, 04:21 AM
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Registered
Join Date: Nov 2008
Location: La Grange, GA
Posts: 5
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Just got done putting the intake manifold back on since I made the rookie mistake of not putting the ISV to manifold hose on. Also just got back from a trip around the block. Where I live, around the block is about five miles of twists and turns. What a RUSH!!! I have been down since August. Thanks for all the help!
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11-28-2008, 09:47 AM
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Redline Racer
Join Date: Jan 2007
Posts: 2,444
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doh..I hate when that kind of silly stuff happens, but glad to hear it's running great.
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1987 silver 924S made it to 225k mi! Sent to the big garage in the sky |
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11-29-2008, 12:02 PM
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1986 Porsche 951
