Ford Mustang Forums banner

1 - 3 of 3 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter #1
I have 2002 Mustang GT I just purchased Someone took wiring harness at engine off so I replaced that and hope it is all correct. Problem when I try to start car I can not hear fuel pump and have no pressure I checked all fuses they are good.Changed fuel pump and checked it before installing it is good I checked inertia switch it has 12 volts from both wires when trying to start but still no sound from pump What would you advise me to go next One more question someone said it may be theft system not letting fuel pump come on I can spray starting fluid in throttle body and car will start for a few seconds but then die Would the theft system let the car start spraying starting fluid in throttle body Please advise me on what to do next THANKS for any help you can give me
 

·
Registered
Joined
·
191 Posts
Yes, the PATS disables the fuel pump. Is the theft light flashing?
 

·
Registered
Joined
·
283 Posts
For the 1996+ Model year Ford factory PATS does not disable the fuel pump. PATS works by with holding fuel injector pulse.

The older model year Mustangs do disable the fuel pump.

After initial prime the PCM will wait until it detects motor has started before restarting the fuel pump. This is why it's important for the fuel pressure to hold between starts.

For the 1996-1998 model year with a return based fuel system the PCM controls the fuel pump via the CCRM. What will be seen is +12 volts at the trunk mounted IFS switch that follows the fuel pump "prime". So when testing at the trunk mounted IFS switch the power will be seen at initial key on for a few seconds. The PCM will switch off power to the fuel pump until motor start is detected.

But why Guess? Test!.

Turn the key but do NOT crank.

Does the check engine light come on? IF not suspect a PCM problem.

Does the theft light go out after a 3 second "prove out"? If yes, then the PATS key has been accepted and as far as PATS is concerned, it's OK to start. There fore if there is a problem with a successful PATS "prove out", it's not PATS related.

Want more proof? When ever the motor is not allowed to start due to PATS reason, the PCM always stores a DTC indicating the reason. Are there any stored DTC codes?

Does the check engine light go out during cranking? IF so, the PCM is receiving a valid CKP signal.
 
1 - 3 of 3 Posts
Top