Help need a ford expert
 

Damn truck. My Ford F150 has an intermittent no start issue. It has left me stranded 4 times and has been to two different shops. The first shop claimed it was the chip reader for the keys. Now the second shop has had the truck for more than a week and can't find the problem.. no codes. The truck start every time and they want me to pick it up, telling me they've gone through everything and can't find the problem.

It's very intermittent. The truck cranks but, no start. The first time this happened, I was at the Lake working on a Friday at 3:30pm. It would turn over but, not start. My insurance covered towing and arranged a tow. While waiting for the tow, I tried starting several times. The tow truck never showed up, the company wouldn't answer the phone. I called a friend to pick me up. He came and arrived at 10:30pm. I then tried one last time to start the truck and it fired right up.

I couldn't get the truck into a shop immediately, the local shops were booked for weeks. So, I had no choice but, to take the risk and drive the truck. I missed 2 days of work because of the no start issues and had the truck towed to my home once...it started after the tow truck driver delivered.

Then on another Friday, the same thing happened at 3:30. Only this time I took a walk to 7eleven and came back to the truck, started it and drove home.

So, Saturday morning the truck wouldn't start. tried again on Sunday, no luck. Bought another truck on Sunday. Had the new truck for a couple weeks. On Monday dropped the F150 off at the second shop. I drove it to the shop. The truck started. They've had the truck for a week and have gone through everything. Starts every time and throws no codes. They checked everything and want the truck gone. The owner says he'll try one more time on Tuesday and that's it.

Maybe I should pick it up and leave it parked by the road with the keys in the ignition.

Anyway, a shop down the road told me they'd look at it if nothing is found on Tuesday. This will be the 3rd shop.

How could a pick up truck be that complicated.

It's a 2007 F150 Lariat with the 5.4L

I had an older Ford that would do that. At first it seemed like a ground issue. I replaced the ground wire and also the negative battery lead. Worked for a while but then after driving it then turning it off it would not start. Turned out I had a bad fuel pressure regulator. Fuel pressure was so high it would flood the engine after I turned off the engine. If I waited a few hours it would fire right up. Check your fuel pressure with a gauge to a schreader valve on the fuel rail.

Check the fuel pump fuse in the engine compartment. The wire is undersized and heats up the fuse box connection. This loosens the fuse and the fuel pump doesn’t work.

There’s a Ford kit you can buy online to move the fuse to another location and splicing it into a heavier wire.

I have a 2000 F-150 that does exactly the same thing. I swear, I take the key out, and flip it over a couple times, and it will start. I have always assumed it has something to do with wear in the steering column, and the chip being too far away. Mine is a 4.6.

Crank position sensor. Easy do it yourself & cheap.

Its either the fuse issue or a failing crank position sensor. Seen it before on 4.6 and 5.4 models.

Look online for any TSB's for your year/model . My son two weeks ago bought a clean used F150 . After a week a check engine light came on . Took it back to the selling dealer ( Ford dealership ) and they said there is a TSB that replaces a sensor and something else . His truck didn't have any running/starting issues but you never know . Doesn't cost you anything other than your time to do some online searching .

Do you not get a 'security' message if the key chip fails to be read? Does the chip cut spark only?

You need to figure out how to diagnose the chip reader first. There must be some indication if the chip has passed or failed. Then you need to check for spark. Then fuel.

There are some good suggestions above, but only after you've narrowed the issue with a bit of work.

It is the DME relay! ;)

Interment issues on any vehicle suck. At least with the 3.2 Carrera there is a neat technical site and every single issue on a G body 911 has been asked and answered dozens of times. I doubt there are many user forums for a new fangled pick-em-up.

I know a friend of mine ended up trading in his Lexus for a random issue no dealer could fix.

This was my thought as I was reading the OP.

If you're even thinking you might have to throw parts at it until you find the problem ... start here.

edit: I didn't spend much time checking fitment but this will give you an idea as to the costs involved and, as noted by Grog, it's an easy job. https://www.amazon.com/Motorcraft-DU-70-Sensor-Assy/dp/B000C5BMW8/ref=sr_1_2?dchild=1&keywords=crank+position+sensor &pd_rd_r=e105fa5e-8a23-4e3e-857f-0bab49116342&pd_rd_w=bMKwQ&pd_rd_wg=UvC6d&pf_rd_p= bec88bc8-d41e-4895-a8dc-a35e165b8995&pf_rd_r=HR0R209QQ2BKSG3FXXFK&pid=Jn5G gep&qid=1622292135&sr=1-2&vehicle=2007-54-666------------&vehicleName=2007+Ford+F-150

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