My Taurus has a similar issue when really cold... Turn the key to Run and listen for the pump. I need to cycle my key 20-30 times sometimes to get the pump to kick in. Once started she's fine. I have done all of the tracing, relay swapping etc. I have a new ignition switch on order as everything else checks out fine. Above 20 degrees, and it never does this.
coincidence ??? crank no start. Ignition vs. fuel pump
- Thread starter rfm77555
- Start date
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update:
Fuses all check okay (using a volt meter).
Already tried the relay swap.
Vehicle was pushed in to my unheated garage, I leaned cardboard all around the outside perimeter of the vehicle, aimed a propane salamander heater under and after 4 hours got a old mercury thermometer on the dash to move from below 15 up to above 35 degrees. At this point I tried to start and it at least fired (not even close to a start) but definitely more than just turning over. (the ignition key by the way, still stayed in the start position the whole time until I manually backed it off to the run position ????)
I still cannot hear the slightest sound at the tank (fuel pump noise)
fuel pressure check attachment point on the fuel rail......removed cover (looks just like a tire valve stem) depressed valve pin and the smallest amount of fuel came out but only once. I expected more pressure here ...am I wrong ????
Going to look for the power supply to the fuel pump to check for voltage there (any advise on this)
Does the power supplied to the pump go to the inertia switch first, as it is easy to get to to check there ???
After that I am gonna try the starter fluid to see if she fires and if so would more likely indicate a fuel supply issue correct ????
The air intake "plumbing" is such a pita....where to disconnect and spray a tiny shot of starting fluid ??? again the cold is no help here at all, everything is so brittle I hate to apply much pressure at any point.
thanks again for all the replies
Fuses all check okay (using a volt meter).
Already tried the relay swap.
Vehicle was pushed in to my unheated garage, I leaned cardboard all around the outside perimeter of the vehicle, aimed a propane salamander heater under and after 4 hours got a old mercury thermometer on the dash to move from below 15 up to above 35 degrees. At this point I tried to start and it at least fired (not even close to a start) but definitely more than just turning over. (the ignition key by the way, still stayed in the start position the whole time until I manually backed it off to the run position ????)
I still cannot hear the slightest sound at the tank (fuel pump noise)
fuel pressure check attachment point on the fuel rail......removed cover (looks just like a tire valve stem) depressed valve pin and the smallest amount of fuel came out but only once. I expected more pressure here ...am I wrong ????
Going to look for the power supply to the fuel pump to check for voltage there (any advise on this)
Does the power supplied to the pump go to the inertia switch first, as it is easy to get to to check there ???
After that I am gonna try the starter fluid to see if she fires and if so would more likely indicate a fuel supply issue correct ????
The air intake "plumbing" is such a pita....where to disconnect and spray a tiny shot of starting fluid ??? again the cold is no help here at all, everything is so brittle I hate to apply much pressure at any point.
thanks again for all the replies
Clemson82
Full Access Members
I'd go straight for the starter fluid. How much gas do you have in the tank? With these temps, if there is water vapor in the tank or line, it could freeze things up.
There should be voltage at both wires on the inertia switch with the key on. If you have power in but nothing going out the switch is suspect. I am not sure where the fuel pump driver module comes into play regarding the flow however.
Bedrck47
Full Access Members
Attached is a copy of the fuel pump circuit As you can see power comes from Fuse #32 Thru the contacts in the fuel pump relay
Then to the shut off switch and then to the fuel pump
Power for the coil off the fuel pump relay comes from fuse #71 and the coil is controlled by the PCM
Then to the shut off switch and then to the fuel pump
Power for the coil off the fuel pump relay comes from fuse #71 and the coil is controlled by the PCM
Bedrck47
Full Access Members
The 07 doesn't have a FPDM
Also if the engine isn't running you may not see a full 12 Volts going to and coming from the shut off switch
This happens due to the PCM not sensing a running engine and limits power to the fuel pump so as not to flood the engine
Very good point! Voltage will be present for the prime only if she doesn't crank and fire up.
UPDATE
Thanks All for the information received.
So all things pointing to fuel lacking after spraying combustible aerosol into intake line and it started and stalled.
Dropped the tank and found fuel pump with obvious heat damage on the negative side.
Install new pump assembly, reinstall tank, and it started right up.
![IMG_0586[1].JPG](https://www.expeditionforum.com/data/attachments/21/21611-a9b72e923f6e3217f8600d835682d988.jpg "IMG_0586[1].JPG")
![IMG_0605[1].JPG](https://www.expeditionforum.com/data/attachments/21/21612-10d60c5f670412d0300711617c59ed6e.jpg "IMG_0605[1].JPG")
Thanks All for the information received.
So all things pointing to fuel lacking after spraying combustible aerosol into intake line and it started and stalled.
Dropped the tank and found fuel pump with obvious heat damage on the negative side.
Install new pump assembly, reinstall tank, and it started right up.
17LimitedExpy
Full Access Members
Wow...that’s a little scary seeing that much heat damage. Glad you fixed it and are back running.
