jleonard711

Well, I'm trying to help out my buddy's wife who is stranded at home with a 2000 F-150 that won't start. The truck has 135K on it, but they have never had a problem starting it. The battery is fine, it has a full charge and all the electrical stuff works fine. And the starter seems to be working because the engine cranks over just fine and it sounds like it wants to start, but it doesn't. One interesting thing I noticed as that the "theft" light on the dash flashes when you are cranking it, but she says that it has always done that, so that might be irrlevant. One thing I've read about here on the fourm is that there seem to be common issues with the PATS module losing the pairing with the key, and thus preventing the truck from starting. Does that sound like the case here? Or will the engine not even crank if it's having that issue?

Also, I noticed that I don't hear the tell-tale "click" or "hum" of the fuel pump coming on when I turn the key to the "ON" position, so does that mean the fuel pump could be bad? I have checked all of the related fuel pump fuses & relays (I think I found 2 fuses and 1 relay), and those are all good. I asked her when was the last time the fuel filter was changed, and she said they've had the truck since 60K miles and it has never been changed since they owned it. So could a clogged fuel filter cause the pump to go bad overnight?

Also, I know that they're oxygen sensor went bad about 6 months ago and they procrastinated in replacing it so the truck has been running extremely rich for the past few months (evident by a HUGE drop in gas mileage), so could the extra stress on the pump of running extremely rich for an extended period of time cause it to bad?

Any input or advice would be greatly appreciated, as she is stranded at home without a truck right now and I'd like to help her fix it.

Fast Hampster

Welcome to the forum! You should begin with fuel pump voltage check, then with fuel pressure check.

jleonard711

Thanks for the quick reply! Where would I check the fuel pump voltage at? I'm not at all familiar with this truck.

As for the fuel pressure - I don't think there is any fuel pressure because the pump isn't even clicking on at all.

Fast Hampster

You woun't believe - me either... you shold manage to perform the check at the pump connectors directly or at the output of the last relay. I have a '93 F150 and i can't hear the pump because of a wizzling warning sound when i turn the ignition on.

jleonard711

I listened for the pump to click on from inside and outside the truck, and it's definitely not clicking on.

Do these truck have an in-tank fuel pump? And if so, how would I check the voltage on the pump itself - wouldn't that require pulling the pump out of the tank?

Fast Hampster

It really has a in-tank fuel pump. It must have some sort of 2-pin connector on the top of a tank. Unplug it and check for any voltage.

ktmboyz

how fast is the theft light flashing? If the pats system is malfunctioning then the pcm will shut down fuel and ignition. You need to rule out the pats first and foremost!!! If you have a scan tool see if it has a p1620 in it

lawaters

This is bad but when I first got my truck 200 Supercrew I had to take it back to the dealer for service and when I got into the truck to take it it would crank but not fire so I had to have it towed. You can imagine how stupid I felt when the service guy called looking for the other set of keys. The ones with the Chip in it. I was taking it in for service so I was using the valet key that came with the truck. That key is now in the trash!! Who knew!!

jleonard711

Yeah, I already thought about trying another key, but apparently the one they are using is their only key. I wasn't able to get anything figured out yesterday, but I pretty much have it narrowed down to either a bad fuel pump or an issue with the PATS system. I'm leaning towards a PATS issue since the theft light on the dash comes on when you try to start the car. I'll check the voltage at the pump, and if it's not getting any power than I'm going to assume it's the PATS which is cutting power to the fuel pump and preventing it from starting. I don't understand why it wouldn't recognize their key though, because it's the only key they have and it's the same key they have always used. But from reading around on this forum, it appears that the PATS system is notorious for acting up and causing random issues like this.

kaboom10

When mine wouldn't start the dealer replaced the crank sensor I believe. It was a new truck and they had to even canabalize the part off one in the lot. It was a 99 F-150.