jleonard711

I have pretty much narrowed it down to either a fuel pump or a PATS issue, because the fuel pump isn't even clicking on when I turn the key forward. If it was a crank sensor then the fuel pump would at least click on, it just wouldn't turn over. So the fact that the pump isn't even clicking on mean one of the following:

1) there is a bad fuse or relay, but I have tested all the fuses and relays and they all work fine.

2) the PATS system is preventing the car from starting, because it cuts the power to the fuel pump to engine from starting

3) the fuel pump is bad.

I think the only way to know for sure is to check the voltage at the pump - and if it's not getting any voltage then it's most likely the PATS issue. But if it is getting voltage and it's just not firing up, then it's going to be a bad pump.

But my dilemma is this - how do I check the voltage at the pump, without dropping the tank? It looks like the pump is on the top of the tank on the driver's side, and there is absolutely no way that I can see getting at it without dropping the tank. I did trace the wires back to the engine bay and I can see where all of those wires plug into the fuse box, but I don't know what color wires are for the fuel pump. Anyone know??

kaboom10

All the wiring diagrams you'll need. Tap into the power leads. http://search.ebscohost.com/Login.as...uthtype=ip,uid login and password is library.

crazykarl

just out of curiousity did ford us an enertia switch on these trucks? I know most ford cars had them... sometimes they owuld get tripped over simple things.

kaboom10

Good idea dude. I believe they're used on all of the vehicles in case it's hit hard. I wonder if the vehicle hit something hard to trip it.

jleonard711

I already checked the inertia switch, and it's all good. I also checked the voltage at a few places, and I found out that there is voltage at fuses #10 & #18 (which are both related to the fuel pump), relay #301 which is the fuse pump relay, and also at the inertia switch. From what I've read, if the PATS system is engaged then it would cut off power to the fuel pump by cutting the circuit which the inertia switch is on. So therefore, if I'm getting voltage at the inertia switch and all of the fuses and relays when I turn the key forward, then that means that power is definitely going to the pump, right? And if voltage is going to the pump, but it's not even clicking on at all, then I would think it's pretty safe to assume that is a bad pump, right?

I know a few people have mentioned that a bad crank shaft sensor is a somewhat common problem, but even if that was bad the fuel pump would still come on when I turn the key forward, wouldn't it?

I think I'm going with fuel pump, final answer... and hopefully it's the correct one! If anyone has any reason to believe otherwise, after reading all of the symptoms and things that I have already checked, speak now or forever hold your piece.

By the way, thanks to everyone for the input, this is an awesome forum! I'm going to tell my buddy that he needs to get on here and do some reading so he can learn all about his truck!

ktmboyz

if you have 12v to the fuel pump and its not running then youre on it! Just make certain the pump isnt running, I use a stethoscope and listen or a screwdriver with my ear on the handle. You can almost always hear it with out but sometimes you get a quiet one. As you prob already know the pump should come on for 2 sec when you turn the key to on or constant power in crank. You can also try to smack the tank with a large dead blow hammer, sometimes it will rattle the pump enough it will restart. I usually do so I can drive it into my bay and change it. Good Luck!!

transmaster

PATS is the anti theft system? I have one on my 95 but the former owner disabled it.

crazykarl

it sux to have to change a fuel pump... not real hard but to have to go thru taking the gas tank down etc... then if it is full of fuel... but id have to say at this point that is probably where you are headed.

jleonard711

I'm finally helping him drop the tank tonight and we're swapping out the pump, so I'll let you guys know if it is fixed.

Red 05 F150

Sorry if I'm hi-jacking this thread but I'm a bit new to site and cant figure out how to post a thread(or am I allowed to). I have a 99 F150 that had the odometer that was blacked out (lights sometimes) because of a crack in the solder joint. I have fixed several of these with no problems, this 1 just cranked at me after the repair and no fuel pump hum, and no security light flashing. It finally started 20 mins later with no explanation, and was fine for a week and did it again, this time ckd fuel pump relay clicking, no security codes is memory, banged on the tank, etc, nothing worked! I get my trailer out to tow it to shop and it fires right up! Fuel pump? or help Thanx!