hi guys yesterday i went to start my truck and it would crank but not fire. i messed around with my intertia switch and the crank sensor checked my fuses and then it fired. it ran fine all day after that, and i went to advanced and got a new crank sensor, fuel filter. its a 2000 with the 4.6 ive been using lucas fuel treatment after every fill for about 2 months and the trucks been fine anyways i went today to go to work and again it would crank and not fire. ive tried everything i could think of and it wouldnt start. when i turn the key i can hear the full pump "whine" but when i used a screwdriver to press the fuel rail only a lil drop comes out......im stuck now and could use any advice thanks in advance

 

Fuel filter changed recently? Time to do a fuel pressure test... see what's going on. If you depresses the shrader valve on the fuel rail moments after you heard the pump prime and all you got was a dribble then it sounds like you dont have enough fuel pressure. It should at the least make a little squirt and pshh sound for a brief second. Pump could be starting to go out, so get that checked.

 

agreed your not getting fuel pressure

 

ok so how would i go about a pressure test. i changed the fuel filter yestersay. and also do u guys think its possible someone could have put some thing in my tank because i ran into a kid who had problems with a friend of mine before all this started, just to wierd for me

 

Places like autozone rent a fuel pressure test kit for a deposit that is fully refundable, which makes it free in the end. Not that I haven't seen someone sabotage a vehicle before but consider it a last resort. For now, confirm you have proper fuel pressure at the rails to rule out a faulty fuel pump. A quick way to get a general idea of fuel pressure is to disconnect the fuel line at the pump side of the fuel filter, hold it into a jar of some sort and have someone turn the key to the on position. You should see a nice squirt of fuel, if you just get a little dribble, the pump is bad. Otherwise, grab the fuel pressure test kit and get a proper reading. The pump priming "whine" your hearing should be a nice consistent hum/whine for about 2-3 seconds.

 

Have you cleaned or replaced your IAC ?

 

ok heres the update i have no fuel pressure so does that mean new pump, sending unit or what

 

No pressure at the filter? New pump time.

 

ok heres the deal....i primed the key a few times and then hit the full rail valve and had pressure i also redid the pressure test after primeing the key a voila perfect pressure. well since this thing was kicking my butt i decided i was going to have it towed to a local shop, anyways the tow truck driver got here and saw the theft light, he told me to try a diff. key i did and the truck started no prob. except for the pressure valve was squirting fuel but i got that pushed down and sealed up and everything is awsome...never thought a key could be the problem, thanks guys for the help we'll see how things go from here, any input?

 

When my fuel pump failed, it failed intermittently ... start fine a bunch of times, then not start, then start fine a bunch of times ...

 

As Fairlaner said above, this is an intermittant problem

 

Time to drop some tank

edit: how many miles are on your truck? I'm close to 240K on my stock fuel pump. I never use more than 2-3 fuel additives a year. That "once a tank" you do might've helped kill it.

 

well like i said the shp said everything was a ok and that my key was the prob, my theft light was flashing wich i didnt catch but a diff. key fired it right up. im going to drive the truck for awhile and see what happens as the fuel pump i replaced about 6 months ago with a ford replacment. the key i was using was a homedepot key and as ive been told they are junk and cause the theft system to shut the fuel pump down? yep and the lucas says add to every fill but im going to stop that

 

A copied non programmed PATS key shouldnt work at all..... Not sure how you have been using it. And of coarse lucas sais add with every fill.... sales sales sales.

 

it was a programable key with a battery my guess the battrey went dead