This is a hybrid. A 4.6 dohc Cobra in a 1956 Chevrolet. My first two Cobras went into a 1955 Ford F-100 and a 1995 Ranger. This project has a fuel problem. When I turn the key on, the fuel pump cycles for about two seconds. However it doesn't pump up pressure. If I hook 12 volt directly to the fuel pump wires, it comes on, loads down and pumps up to 40# in a few seconds. The engine then runs for about 5 seconds until the fuel runs out. I traded out the fpdm. No luck. I get a P1639 code. I'm wondering if the PCM could be commanding the driver to keep the pulse regulated voltage low so the car won't start. PATS is disabled supposedly. On a regular Mustang, what would be the symptom if someone tried to start the car without the correct key? Would the pump cycle? Thanks for any help.
Fuel pump doesn't pump up pressure
56heretic
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This is a hybrid. A 4.6 dohc Cobra in a 1956 Chevrolet. My first two Cobras went into a 1955 Ford F-100 and a 1995 Ranger. This project has a fuel problem. When I turn the key on, the fuel pump cycles for about two seconds. However it doesn't pump up pressure. If I hook 12 volt directly to the fuel pump wires, it comes on, loads down and pumps up to 40# in a few seconds. The engine then runs for about 5 seconds until the fuel runs out. I traded out the fpdm. No luck. I get a P1639 code. I'm wondering if the PCM could be commanding the driver to keep the pulse regulated voltage low so the car won't start. PATS is disabled supposedly. On a regular Mustang, what would be the symptom if someone tried to start the car without the correct key? Would the pump cycle? Thanks for any help.
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This thread is useless with out pictures !!!! hahaha sounds like some bad ass rides
It would really help to know what model year PCM is providing engine management and if this is a return or return-less fuel system.
FWIIW, for the 96-02 model year, PATS does NOT disable power to the fuel pump or fuel pump driver module. There should be power at the trunk IFS switch the ENTIRE time the ignition switch is on.
PATS disables the motor by with holding the injector and spark pulse.
A couple of pieces of information would make short work of this if you have an ODB2 scanner.
Does the RPM's change during cranking?
Does the air flow (MAF) change during cranking?
If a "noid" style test light is used on the fuel injectors and the COP's, do they pulse?
FWIIW, for the 96-02 model year, PATS does NOT disable power to the fuel pump or fuel pump driver module. There should be power at the trunk IFS switch the ENTIRE time the ignition switch is on.
PATS disables the motor by with holding the injector and spark pulse.
A couple of pieces of information would make short work of this if you have an ODB2 scanner.
Does the RPM's change during cranking?
Does the air flow (MAF) change during cranking?
If a "noid" style test light is used on the fuel injectors and the COP's, do they pulse?
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