hello a friend just ask me to look at his 08 f350 diesel .i work on gas engines so not really familiar with the 6.4 .so the truck just cranks does not start does not even try to start there is no codes .is there anything i should look at first or check.i have a standard obd2 scanner and no specialty diesel tools.i read something about fuse #72 and the inertia switch on passenger side i will check both.any help would be appreciated thank you
ssls67
Monitor your frp see if it’s rising to 5000psi it will not even try to start if it does not see 5000psi
Was anyone in there prior changing fuel filters or anything? There could be air in the system.
If not then proceed to check low pressure
Key on, do you hear a buzzing from under the truck driver side below the door? There is a low pressure fuel pump.. there if you don’t hear the pump running and or fuel being sucked from the tank. Suspect a dead pump or power/ground issue..
If good then hook up a fuel gauge to the shraeder valve at the fuel cooler and look for 6-8psi you can have 1-3 on certain applications I’ve seen that. There is a bleed off valve in the fuel filter could have a restriction.
You need to monitor your fuel rail pressure. It has to hit atleast 5000psi or it will not try and start. The pcm detects the 5000psi signal, then turns on the injector driver and fires the injectors. If you have a bad hpfp you can have this issue and no codes. Usually you should have a p0087 or p0088 code. Also there is a TSB about the HARNESS chaffing under the pump cover causing an open in the harness to the pcv and vcv valves.
If you have no rail pressure you can have a bad pump, harness chafed, leaking injectors OR a bad low pressure fuel pump.
If that all checks out I’d check for a security issue and or a start command on a scan tool. Signifying that the pcm detects theft and will not allow it to start.
Report back.
Sent from my iPhone using Tapatalk
Was anyone in there prior changing fuel filters or anything? There could be air in the system.
If not then proceed to check low pressure
Key on, do you hear a buzzing from under the truck driver side below the door? There is a low pressure fuel pump.. there if you don’t hear the pump running and or fuel being sucked from the tank. Suspect a dead pump or power/ground issue..
If good then hook up a fuel gauge to the shraeder valve at the fuel cooler and look for 6-8psi you can have 1-3 on certain applications I’ve seen that. There is a bleed off valve in the fuel filter could have a restriction.
You need to monitor your fuel rail pressure. It has to hit atleast 5000psi or it will not try and start. The pcm detects the 5000psi signal, then turns on the injector driver and fires the injectors. If you have a bad hpfp you can have this issue and no codes. Usually you should have a p0087 or p0088 code. Also there is a TSB about the HARNESS chaffing under the pump cover causing an open in the harness to the pcv and vcv valves.
If you have no rail pressure you can have a bad pump, harness chafed, leaking injectors OR a bad low pressure fuel pump.
If that all checks out I’d check for a security issue and or a start command on a scan tool. Signifying that the pcm detects theft and will not allow it to start.
Report back.
Sent from my iPhone using Tapatalk
ok checked fuel pressure at schrader valve aprox 6-8psi ,key on scanner readings ECT 46 degrees,MAP 30inhg ,IAT 50f ,MAF 0.17 lb/min ,fuel pressure 0 ,fuel level 76.1% its aprox 3/4 tank, BARO 30inhg, cat te11 50f ,cat te12 46f ,ECM volts 12.01 .engine cranking fuel pressure is aprox 6700psi slowly goes down as its cranking on its own to aprox 4953psi then stops cranking goes back to 0 till you crank it again.i still will check for chafing wires at fuel pump on frame.not sure how to test security system.thank you for the help and your time
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