Engine won't crank

Ford12508 · #1 02-05-2012, 05:54 PM

I have a 2007 F150 XLT 5.4L. Everything electrical in the cab seems to work, my headlights also work, but when I try to crank the truck, nothing happens whatsoever. I do have electric fans hooked up, they only come on when the ignition is in the "On" position. They still come on if I turn the key to "On" so I dont think it is an ignition problem. I hit my starter a few times praying that would be the issue, but it didn't have any effect. Anyone have any ideas what it could be or do you need any more details?

Here is a detailed list of my situation:
Drove to work and truck sat all day
Dont remember if it stumbled or not when I started it after work, but sometimes it had issues wanting to start but it was because of the PATS system
Left work, got to my friends house which is like 250 feet and downhill from my house
Went to leave 30 minutes later, truck wouldn't crank over but all electronics worked. Voltage was fine.
Checked the wiring for the ignition since I have a kill switch. All the connections I made were fine and tight.
PATS system is checking out fine with my keys(I tried multiple)
Swapped the High beam relay and the starter relay(Same relay)
Wiggled the solenoid wire at its connection, no luck
Smacked the starter a few times, I know when they go, sometimes you can hit them.

azmidget91 · #2 02-05-2012, 06:36 PM

There is a little wire that runs along the battery cable down to the starter, near the battery there is a little connector that looks almost like an inline fuse. Wiggle that connector around

SSCULLY · #3 02-05-2012, 10:31 PM

Nothing as in no crank no start ?

When you turn the key from run to start, every thing else turns off, correct ?

Ford12508 · #4 02-06-2012, 09:38 AM

Yes, the radio turns off and everything seems normal, just no crank.

Just checked the PATS system. The light blinks normally with the key out of the ignition. When I turn the key to the ON position, it goes solid for about 3 seconds and then goes off. When I try to crank it, it just stays off.

88racing · #5 02-06-2012, 09:45 AM

What's the system voltage reading?

Ford12508 · #6 02-06-2012, 10:09 AM

Quote:

Originally Posted by 88racing

What's the system voltage reading?

12.2V, tried swapping the battery already on someone else's advice, truck acted the same way. I also left the battery out overnight and reinstalled it this morning, nothing.

Ford12508 · #7 02-06-2012, 10:18 AM

Quote:

Originally Posted by azmidget91

There is a little wire that runs along the battery cable down to the starter, near the battery there is a little connector that looks almost like an inline fuse. Wiggle that connector around

Tried finding this wire, didn't really see anything. I will check again though.

Im also going to swap the starter relay

Ford12508 · #8 02-06-2012, 10:40 AM

Swapped the relay, no luck. Found the small wire from the starter, it was right in front of my face haha. Wiggled that and nothing. I think the starter might be shot.

I didn't think to add this before, but I have gone wheeling with the truck, the starter has probably been completely submerged a few times. Most recent wheeling adventure was a couple month ago.

Ford12508 · #9 02-06-2012, 11:32 AM

Also, there is no click from the starter when I attempt the crank the engine over. Sorry about the multiple posts, everytime I try or think of something I just want to keep everyone here updated in case it makes them think of something

SSCULLY · #10 02-06-2012, 02:51 PM

Seems the ignition switch is working correctly ( as well as PATS, but that would be a crank no start issue ), so next is on to the DTR ( digital Transmission Range ) sensor circuit.

2 tests for this.

1. Turn key to on, press and hold the brake and shift into Neutral, turn key to the start position.

If this is same symptoms :

2. time to check the circuit from the ignition switch to the starter motor relay in the fuse panel.

Pull the starter motor relay, the coil pin ( #86 ) will have power on it when the key is in the start position.
Use a meter to check for + VDC when the key is in the start position.

If you do not have + VDC here when the key is in the start position, either you have fuse # 102 blown or the DTR is no good.

Check at the DTR ( from 2006 EVTM )
Ign switch ( start position ) -> Red w/ light Blue stripe wire -> fuse panel ( no fuse here ) -> Dark Blue w/ Orange Stripe Wire -> DTR -> Tan w/ Red stripe wire -> Fuse panel ( to starter motor relay ).

With the truck off, you can meter for resistance or continuity from the Dark Blue w/ Orange stripe wire to the Tan w/ red stripe wire, and it should show < 50 ohms or continuity.
- If not, the DTR is no good, and needs to be cleaned or replaced.

Something is telling me the 2007 My had the starting diode added to the mix, so this might change things slightly in the layout. The starting diode is for when the key is turned to the start position and held for 1 sec, you can release the key and the truck will continue to keep the normally open contacts on the starter motor relay closed until the truck starts or until 5 ( 8 ?) seconds passes, at which point the normally open contacts return to that position.

Ford12508 · #11 02-11-2012, 12:58 PM

Thanks SSCULLY, I have a factory service manual and looked at all the wiring diagrams and ruled everything out. Turns out my fuse box went bad(Again...). I believe the remote starter was to blame for this. This would have been the third fuse panel on the truck in the last 15 months, but luckily I was able to just wire around the box and install a switch.