So, I have a 1999 f150 4.6L 5 speed extended cab. And I'm trying to understand the issue I'm having, I can not for the life of me figure it out. And I've literally looked every where. So when I turn the key on my fuel pump primes, but that' all It does and it stays on pressure gauge says it' good I have fuel running threw the entire system. I've changed the fuel filter, relay, regulator, and crank shaft posiion sensor, I have spark. And all fuses, relays and circuit breakers are good. It cranks like a champ. It just will not turn over and start and stay running.

 

If you have positively verified you have spark, either the injectors aren't firing or the IAC is stuck closed.

Try starting it with your foot slightly down on the gas pedal. If it starts, the IAC isn't working.

You can test the injectors with a set of noid lights. Autozone has them for $25. They, and other parts stores, may have them in their loaner tool kit.

https://www.autozone.com/test-scan-a...ter/948078_0_0

 

So when I have everything back together with my gas pedal pushed or not it will not start period. However if I take the fuel pump relay out after cycling the key a few times back and forth it'll start but obviously die out because the relay isn't in I don't know where to go from there.

 

What is your fuel pressure? Needs to be at least around 28lbs. to start.

 

[QUOTE=JCR 56;5234076]What is your fuel pressure? Needs to be at least around 28lbs. to start.[/QUOTE]

I have 40psi
did some research and with the key on not running it' 35-45 psi. I do not remember what it' supposed to have when running but I'm clearly not there yet.

 

1999? You have PATS? Can't remember what year that started, maybe 1999 or 2000

 

Spoiler

 

 

Quote:

Originally Posted by Patman

1999? You have PATS? Can't remember what year that started, maybe 1999 or 2000

Yes I do have a PATS system

 

And are you getting a flashing theft light while cranking?

 

Quote:

Originally Posted by Patman

And are you getting a flashing theft light while cranking?

I am getting a pretty rapid flashing, I've had the thought I've just never have messed around with a PATS system before

 

That's a PATS issue. Try your other key. You either have a key with a defective chip or the transceiver around the key switch has a problem.

 

[QUOTE=glc;5234100]That's a PATS issue. Try your other key. You either have a key with a defective chip or the transceiver around the key switch has a problem.[/QUOTE]

so out of curiosity, if the transponder or the chip in my primary key is going out, would that cause my fuel pump to always prime and not shut off after 2-3 seconds?

 

I wouldn't think so.

 

Quote:

Originally Posted by glc

I wouldn't think so.

that's my other issue. When I cycle the key back and forth with the fuel pump relay in obviouly pressure builds in the cylinders. However when I crank it, it will not start. But if I cycle it and take the fuel relay out it will start but die after a few seconds with out the supply of fuel.

 

PATS disables fuel pressure, that's why you're getting the priming, but no fuel during cranking.

Need to diagnose PATS first. Trying a second chipped key is a good quick check

 

[QUOTE=Patman;5234126]PATS disables fuel pressure, that's why you're getting the priming, but no fuel during cranking.

Need to diagnose PATS first. Trying a second chipped key is a good quick check[/QUOTE]


I've tried both and I don't rememer what the other key did. So something I forgot to mention I flashed my PCM during this entire process does that delete the chip codes out of the PCM?