2001 f150 supercab 5.4 - fuel pump primes, cranks but no start.
#1
2001 f150 supercab 5.4 - fuel pump primes, cranks but no start.
Hi All,
So have an issue that I started to track down last night but ran out of time. Went to start the truck and it would crank but not start. Hooked fuel pressure gauge up and had 0 fuel pressure on the rail. Disconnected fuel filter, when i turn the key on, it primes for 2 seconds like it should every single time and shoots a good amount of gas out. But when I crank, it is not pump any gas. I didn't get a chance to physically check for spark yet, but when I spray starting fluid, the truck does almost start for a half second so I am assuming there is spark.
I was thinking tonight to try the crank position sensor first but I would think if it would start on starting fluid that would be okay. I would assume the fuel pump relay is okay since it primes fine everytime?
Just seeing suggestions on what to try if i should go ahead with the crank position sensor then what to trace next, whether to drop the tank/remove bed.
I have ensured the theft light does not blink and the intertia switch is not tripped. I have also checked all fuses.
So have an issue that I started to track down last night but ran out of time. Went to start the truck and it would crank but not start. Hooked fuel pressure gauge up and had 0 fuel pressure on the rail. Disconnected fuel filter, when i turn the key on, it primes for 2 seconds like it should every single time and shoots a good amount of gas out. But when I crank, it is not pump any gas. I didn't get a chance to physically check for spark yet, but when I spray starting fluid, the truck does almost start for a half second so I am assuming there is spark.
I was thinking tonight to try the crank position sensor first but I would think if it would start on starting fluid that would be okay. I would assume the fuel pump relay is okay since it primes fine everytime?
Just seeing suggestions on what to try if i should go ahead with the crank position sensor then what to trace next, whether to drop the tank/remove bed.
I have ensured the theft light does not blink and the intertia switch is not tripped. I have also checked all fuses.
#2
#3
hi Roadie, Thanks. Yes fuel pressure at rail was 0. So i removed the fuel filter to attempt to test pump before dropping tank or going any further. When i turn key on (not to crank) the pump primes fine. But when I go to crank it, it is not pumping/spitting fuel like I would expect. I guess what I am asking is when I am cranking the truck, should the fuel pump be throwing fuel with fuel filter disconnected because it is not. It only throws fuel when I prime it.
Last edited by atroyan84; 06-16-2017 at 08:44 AM.
#4
If you cycle the ignition to run only 4 or 5 times and pressure builds and holds, leave the pump alone.
The problem is the PCM is not getting the signal from the crank sensor to operate the pump relay during cranking.
This also means no ignition and no fuel injector operation because they all depend on the crank sensor signal to make the PCM apply grounds the all these in their normal order..
Good luck.
The problem is the PCM is not getting the signal from the crank sensor to operate the pump relay during cranking.
This also means no ignition and no fuel injector operation because they all depend on the crank sensor signal to make the PCM apply grounds the all these in their normal order..
Good luck.