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fuel pump wont prime sometimes

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Old Dec 2, 2009 | 01:00 PM
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Default fuel pump wont prime sometimes

For the past few months at random times my heads/cam car will not prime. i turn the key to run and nothing. of course, if i try to start it it doesnt run. but if i unhook the battery, wait 30 seconds, and hook it back up the pump primes and it fires right up. It very rarely does it on cold starts but seems to happen mostly on 5-30 minutes starts after running.

I figured it was my fuel pump so i replaced it with a direct replacement racetronix fuel pump but it didnt help. Also i can hear the relay clicking even when it doesnt prime so ive pretty much ruled them out. this is my third post about and no one has been able to help or even give me some plausible solutions. ive tried everything and nothing but reseting the battery helps. Ive damn near given up on the car. someone please help
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Old Dec 2, 2009 | 02:00 PM
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Without the signal from the key resistor the BCM won't enable the starter or
send the signal to the PCM to enable the fuel pump.

Sometimes if I don't have the key fully seated in the ignition
the engine won't crank or it will start and immediately die.
A dirty key resistor can cause this as well.
Attached Thumbnails fuel pump wont prime sometimes-701417.gif  
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Old Dec 2, 2009 | 02:54 PM
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this makes so much sense! because sometimes i cant get the starter to crank either but after a few seconds it will finally kick in. you say the key resistor may be dirty, is that the small black box on the key near the grip?
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Old Dec 2, 2009 | 04:22 PM
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Yes.
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Old Dec 2, 2009 | 05:59 PM
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Is there a way to remove this feature (PIA) with tuning?
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Old Dec 2, 2009 | 06:21 PM
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Not just with tuning.
Change parameter {G1201} type of anti theft system the vehicle uses from PWM to None and bypass the BCM to the starter relay. (diagram)

Most people install resistor(s) that match the key
between the BCM and the ignition cylinder.
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Old Dec 2, 2009 | 06:39 PM
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Originally Posted by shoemike
Not just with tuning.
Change parameter {G1201} type of anti theft system the vehicle uses from PWM to None and bypass the BCM to the starter relay. (diagram)

Most people install resistor(s) that match the key
between the BCM and the ignition cylinder.
How can you find out what resistor is needed?
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Old Dec 2, 2009 | 08:05 PM
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Measure your key.
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