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Registered User
Join Date: Oct 2014
Posts: 5
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83 944 run in start position only
I have a 83 944 that runs only when key is in start position. I replaced the ignition switch, speed and ref sensors and temp sensor and dme relay. It has good spark, 30 psi fuel pressure. When running in start position, the noid light at the injector blinks bright. when key is released to run position the noid gets very dim and the engine seems to wind down until it dies. All grounds have been checked and cleaned. With key on and all injectors disconnected it has battery voltage on one term. and 10.4 volts on the other term. i hope someone can help. Thanks
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10-14-2014, 04:13 PM
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944 addict
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What terminals are you measuring?
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3 944's, 2 Boxsters and one Caman S, and now one 951 turbo. Really miss the Cayman. Some people try to turn back their "odometers." Not me. I want people to know 'why' I look this way. I've traveled a long way and some of the roads weren't paved. |
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10-14-2014, 06:37 PM
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Registered User
Join Date: Oct 2014
Posts: 5
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measuring the terminals at the injectors, with all injectors unplugged
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10-15-2014, 03:24 AM
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Registered User
Join Date: Oct 2014
Posts: 5
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update : The car will idle if propane is feed through the vacuum port on the intake. it seems to be starving for fuel while in the run position.. Im thinking the dme /ecu is bad. thanks for any and all suggestions
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10-15-2014, 04:31 PM
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Registered User
Join Date: Oct 2014
Posts: 5
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Come on someone give me some advice, even if its wrong , i'll take it
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11-05-2014, 02:25 PM
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Registered
Join Date: Apr 2007
Location: Fairbanks, Alaska
Posts: 345
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ok. It sounds like you've already tested your fuel pressure.
How about getting the injectors rebuilt? I guess they could have some buildup that is restricting flow. I used witchhunter performance for mine. Pull the plugs and see what they look like. Check the AFM - does in move freely? is the variable resister swipe worn out? Is the exhaust plugged? Check for a vacuum leak - others have rigged up a vacuum cleaner discharge or air hose to pressurize the intake and/or exhaust (carefully). I'm sure others will chime in.
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Red 83 944 |
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11-10-2014, 04:18 PM
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Registered
Join Date: Jul 2007
Location: Ontario
Posts: 22
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Not sure if this applies to 944s or not but in Bosch fuel injection with a mechanical AFM the ECU must see a signal from the AFM to keep the fuel pump relay operated after the key is released from the start position. The pump runs for 10 seconds when the key is first turned on which is enough to run the car for at least 15 seconds at start which causes the AFM vane to move and send the signal to the ECU. So... check your AFM with a ohm meter. I like to use a analog meter for this because it is easier to see momentary opens with an analog meter.
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11-10-2014, 04:50 PM
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Registered
Join Date: Feb 2001
Location: Buzzards Bay, Ma, USA
Posts: 620
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Jumper out the dme relay at terminals 30, 87, and 87b.
This will cause the fuel pump to run continuously (remove after test!). If the engine then runs you might look at another relay, the ECU or the AFM as mentioned above. The staff at ECDdoctors.com (800 328 1425) were very helpful when I got towed home and might have some advice. They can also send you a checklist for all the inputs/outputs of your ECU that may be helpful. I had a copy but lost it somehow. Jon Jon
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87 924S 82 924-Gone. 80 924 parts car-Gone. |
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11-10-2014, 05:23 PM
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Porsche 944 NA
1986 Porsche 951
