Car won't start after swap to A4
08-26-2003, 01:10 PM
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Car won't start after swap to A4 A buddy of mine swapped in an A4 tranny from my car. We traded everything, ie: PCM, engine harness, pedal assemblies, shifters...
His car is all put together, cranks over but won't fire. Does the chip in the ignition key have anything to do with the PCM? Could the PCM from my car require my ignition key? Just wondering before we take apart our steering columns.
TIA..
His car is all put together, cranks over but won't fire. Does the chip in the ignition key have anything to do with the PCM? Could the PCM from my car require my ignition key? Just wondering before we take apart our steering columns.
TIA..
08-26-2003, 02:04 PM
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Re: Car won't start after swap to A4 It doesnt sounds like VATS to me. They measure resistance in each key but I thought they were all the same. I had the VATS problem and my car would start for about 2 seconds then die. Is your fuel pump priming? Good fuel pressure?
08-26-2003, 03:05 PM
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Re: Car won't start after swap to A4 It's funny you mention fuel pressure. He says the injectors aren't squirting fuel. He thinks it's related to the security chip in the key.
BTW..I haven't finished installing everything on my car. So I don't know if there will be the same problem.
BTW..I haven't finished installing everything on my car. So I don't know if there will be the same problem.
08-26-2003, 05:00 PM
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Re: Car won't start after swap to A4 There are several differant resistance vales for the security keys. I doubt the two are the same. I used to measure the resistance of the chip in the key, go to Radio Shack and buy a resitor of that or real close value. Connect the resistor between the two orange leads going to the key switch assembly. Don't know if the F-bodys are the same but I used this method so I could buy cheap extra keys before. I am not sure if the newer vehicles will reconize this as the key still in the ignition and prevent the door locks from working. If you try this to see if the cars start be sure to use the key that went with the PCM.
08-27-2003, 09:01 AM
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Re: Car won't start after swap to A4 change the pcm's back to the original car and get them programmed for the tranny. it won't start bc the pcm does no recognize the key. swap them back and it will start. i have been through this already but i did not swap pcm bc i knew it would not start.
08-27-2003, 09:39 AM
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Re: Car won't start after swap to A4 are you sure the PCM does not recognize the key..
as far as i know, the PCM does not recongize the keys, the BCM does, did you swap those? If so, swap those back, and you should be fine.
the BCM supplies the PCM with the 50hz Square wave when the keys match, to allow the car to run.
Ryan.
as far as i know, the PCM does not recongize the keys, the BCM does, did you swap those? If so, swap those back, and you should be fine.
the BCM supplies the PCM with the 50hz Square wave when the keys match, to allow the car to run.
Ryan.
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08-27-2003, 03:49 PM
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Re: Car won't start after swap to A4 Maybe this is REALLY stupid advice, but you know the switch that detects the clutch position? When you removed the clutch pedel, did you make sure that switch was set in the proper position? I believe it has to be closed, but I can look later today on my car.
08-27-2003, 06:25 PM
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Re: Car won't start after swap to A4 Well, the BCM tells the PCM that the keys match then the PCM sends fuel to the injectors. (one of two things it does upon startup) So, just because the BCm is involved, doesn't mean the PCM isn't either.
08-27-2003, 08:28 PM
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Re: Car won't start after swap to A4 actually it was not the key at all, it has something to do with the PCM. when we move the PCM around it tries to ground itself, and when it is grounded the car starts up just fine. We double checked all the grounds and they are all hooked up. can anyone else think of a way to ground it that will work? I am thinkning about running another ground wire from the pcm box screw to the firewall, it will start up then but will it fry the elctrical system??? thanks could use the help as soon as possible.
08-28-2003, 11:25 AM
#11
Re: Car won't start after swap to A4 it has nothign to do with the key, i have swapped 2 diffrent pcm's into my car from junk yard cars with no problems.
that doesnt make sense that you need to ground the pcm to the car...i know you checked that all the grounds are in, but it could be a signal wire instead of a ground, just cause theres a wire on the pin doesnt mean its a ground.
that doesnt make sense that you need to ground the pcm to the car...i know you checked that all the grounds are in, but it could be a signal wire instead of a ground, just cause theres a wire on the pin doesnt mean its a ground.
