2001 F150 won't start
 

OK I've searched but can't seem to find the exact solution...

My truck is an 01 XL Sport 4.2 auto with about 56k miles (this was my grandfather's truck).

About 6 months ago the battery died so I took it to Autozone and bought a Duralast Gold (700 cold cranking amps). Truck started right up, then it died on me trying to leave the parking lot. Tried both keys. Never would start back up. It was trying to turn over but nothing. Had it towed to a mechanic and they reset the security codes and it was fine. Ran good since then.

Tried to start it up Sunday night and it wouldn't start. I did use a key I hadn't used in awhile. So I tried the other key- no bueno. Then Monday morning I tried to start it with the key I'd been using and it started right up. So I was thinking could it be the key? Tried to start it today (with the key I've been using)- nada! Ideas? Any help is appreciated!

Any problem starting it with the key will result in the theft light blinking quickly. Aslo, PATS (the security system) will NEVER shut the truck down after it has been started.

Any codes? Is it not getting fuel or spark when it won't start? No way to tell what direction to go without more info, but it isn't PATS.

considering that it starts and then shuts off...I'd lean towards the fuel filter. or a relay that runs the fuel pump.

when it is running...does it run OK? nice and smooth or kinda rough?

Also when it does start...does it spring to life normally ??or does it spit and sputter and eventually smooth out??

I hear ya that makes sense the PATS shouldn't shut it down. But that is what I was and am getting. Theft light blinks quickly and the odometer reads dashes. The mechanic I had it towed to last time said it had security codes. They reset it and like I said it was good until now.

It isn't shutting off now- it only did that the one time after I changed the battery. Now it won't start at all. It'll turn over like it is trying to but it won't start. Was running fine and when it did start it started right up. I guess it is possible it could be something entirely new this time.

That means the cluster lost communications with the PCM. Most commonly, it's due to a disruption in the power supply to the PCM, most notably caused by a failing PCM Power Relay or a degraded connection in that circuit.

Replaced PCM Power Relay. No dice. I hope the cluster isn't the culprit because the truck has such low miles. If I ever did try to sell it no one would believe the mileage with a different cluster. But I have no plans to get rid of it. Anyway I guess I'm going to have to have it towed to my mechanic again...:surrender:

What are your CURRENT observations about what's going on in the cluster when you try to start and it fails to do so? You've got old and new stuff mixed in there and it's hard to try and sort out.

I made a video. Sun glared a bit but I think you can see the theft light flashing.

Thats not pats or a cluster problem. Check your FUEL PRESSURE WITH A GAUGE! Replace the filter first!

That could possibly be the culprit. I have changed the filter since I've had it but it has been awhile. I did uses a OBDII scanner ($50 at Autozone) and it will not read. Keeps coming back with "error". Used the unit on two other vehicles so I know it works. :think:

It fires! You have a fuel problem! could be the scanner isnt making a good connection. I have a problem like that with my GM van. only my brother inlaws snap on will work on it. The symptom starting it indicates a fuel problem. Get a GAUGE and test it! should be at least 38 psi!

You mean 28 psi. 40 is spec.

Check your cig lighter fuse, the OBD2 port gets its power from it.

Got the old gal to start up today! Then she died...Currently being towed to my mechanic. I'll update when I hear something.

Update: Mechanic called and said it is PATS. Locksmith will be looking at it on Monday.

It's not PATS. If it starts at all, PATS is working. PATS will never cause the car to shut down. It's like the guard at a gate. Once you show him your badge and he lets you in, you're in. He doesn't keep checking your badge as you walk around.

Did your mechanic successfully pull codes? You have a PCM or electrical issue causing the PCM to malfunction. If you replace the PCM, THEN you'll have a PATS problem.