Ford Completly Stumped

CVPI06

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Hey everyone I could really use some help. First off I am not a master technician. I know a ton on suspension and brakes,
electrical and engine performance are not my strong suit.
I have a 2006 P71 (Crown Vic interceptor) currently around 109k miles. The issue is;
temps below 20 degrees and the car sits for about 2.5 hours it will not start the first time. If it is warmer the car will fire up without issue.

Vehicle cranks and cranks and cranks but will not fire up
until the 4th or 5th try. I have taken the car to 3 ford
dealers in the past 3 years with no answer to what the problem
could be.

Parts I've replaced in the past 2 years (maint. and just recently trying everything to cure the problem); Intake, maf, tps, tb motor, completly cleaned tb and plenum, fuel pump (1.5 y/o), fuel filter (1.5 y/o), new cop's, plugs, coolant head temp sensor, egr, camshaft sensor, and finally what I thought the fix would be - the fuel pump driver module (I got this at the junkyard to test my theory, it did not work. Figured I can't get a bad one what are the chances?) Next only reasonable option would be a new/used pcm to test?

Anyone here able to help me figure this out??
 

tinfoilhat

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Battery?

When my battery was starting to go bad it wouldnt start when it was cold but would start everytime when warmer.
 

daturbosix

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with it being an ex squad, there are always possibilities of wiring issues.. i would check the PCM relay and the fuel pump relay as both are known for getting lazy with age.

also make sure your fuel pump is infact coming on with key-on before starting.
there is a inertia switch the interrupts the fuel pump circuit in the trunk that is also known to become weak with age, however they usually fail to the point that you have to physically reset the switch for the vehicle to start.

there is no fuel pressure test port on these cars. so the only way to check is with a scanner.

also ford computers can be very picky about how much voltage they get. ive seen some that will start at 10.8 volts, but if theres 10.2 volts, she wont run. so if there is a excessive amount of resistance in a circuit you would see a voltage drop..

check all the main grounds for the car. there are a few behind the rear seat, and ALOT behind the passenger side kick panel.

and i also like to gut all the police wiring from the vehicle when i buy one. i dont want anything extra in that car causing issues down the road.
 

CVPI06

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Fuel Pressure is good. Pump kicks on. Ive never looked at the relays. I guess I can just go and buy them they cant be that expensive. There are no extra wires that Ive came across. Only wires disconnected but those were under dash
 

Dasfinc

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I see you replaced the cam sensor, don't these cars have a Crank sensor as well that can cause random no-start conditions?
 

Zack

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Someone is having this exact issue on Facebook,
The dealer disconnected the EVAP system last I checked and he was going to see if that fixed it.
 

CVPI06

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I have the crank sensor on hand. Going to get to that hopefully today. That person on Facebook is me lol. I am tapping into all areas!
 

daturbosix

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you can swap the relays with your defrost and a/c ones.. to try.. i like to use a paint marker and write what position they were originally in to help keep track
 

daturbosix

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There are no extra wires that Ive came across. Only wires disconnected but those were under dash
do you have a harness that does nothing and goes to nothing in the trunk, comes up on the passenger side of the rear seat area?
 

daturbosix

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ImageUploadedByTapatalk1424798331.553052.jpg

This is the extra police harness that I pulled out of my car when I got it
 

CVPI06

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Nope. The only wires in the trunk are the auxilary power. Ive had my seat out and never saw that.
 

CVPI06

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you can swap the relays with your defrost and a/c ones.. to try.. i like to use a paint marker and write what position they were originally in to help keep track
From what i'm reading in the owners manual they all have different amperages. I read this was a possibility but that was on a 05.
 

DJ

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I feel in this situation you need to start from the beginning and see if you are missing your spark or fuel because it's obvious one has been taken out of the equation. Can always go old school, pull a plug, ground it to the block and have someone bump the ignition.
 

Wrencher

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Fords turn the ses of cranking with a valid crank synch signal just FYI. < look for....
I'm betting it's not building fuel pressure on a cold start.

Tried cycling the key on those cold starts (without cranking engine) to see if it alleviates or lessens the symptom?

If you have a scan tool you can what the fuel pump command to the FCM.
Also can check the fuel rail pressure sensor build up with the scan data.

But usually I end up with a flow/pressure gauge & a oscilloscope to find these.
Checking the pressure/flow & current ramp the pump with a scope on a cold start.
Those & the pcm's commanded duty cycle to the fpm.
You put a pump in...a decent one?
 

CVPI06

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Problem solved. Turns out the junkyard fpdm was also bad. I guess I should play the lotto now since I found a panther in the yards with possibly the same issue. Anyway I used that credit for another module and presto problem solved.

Thanks everyone for the ideas and help. I'm going to call the last dealer i left my car at for two weeks and brag about I how found it but not tell them the exact problem.
 

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