Sometimes won't start warm.
 

2001 super crew 4X4 5.4. Truck will start the first time of the day, drive it for a while and shut it off, and sometimes it will not restart. It may just at first go a bit, like just pop off then sputter and then nothing. Can crank and crank, no more sputter what so ever. Can try repeatidly over next 15-20 min. sometimes will pop off sometimes won't, and come back a couple hours later and it will go. Any time it does decide to go, it usually fires up and idles normally as if every thing is fine. no sputter or hesitation down the road.:unsure:

I have a gut feel something electrical. Just don't know.

I have the same exact problem in my 1987. I hope we get this figured out.

Good day,

Replace your Crank Position Sensor... The computer uses the CrankPS to start the vehicle, then fine tunes timing with the CamPS... The symptoms you are seeing is the classic failure for the CPS!!

Good luck!!

Cheers!!

CPS or ECT
 

First off, thanks for the reply!:thumbsup: 00bigred

secondly, I have also come across info that points me to the engine coolant temp sensor. Theory being that it is falsely reading cold engine, and thusly dumping unneeded fuel during warm starts and flooding the engine. If this is true shouldn't my temp guage not be working? Also, I have been finding conflicting info as to whether a 2001 5.4 has a seperate ECT sensor or if it is derived from the CHT sensor.

Is the CPS located behind the AC compressor on the 5.4?

If this helps diagnose the fix:
The only way to get the truck to start if it acts up, is to hold the accelerator to the floor, crank for a few seconds, release the accelerator, while still cranking, and then it fires up.

Thanks!

Suggest both of you members have your codes pulled. Throwing parts at it isn't very economical. Use the system as an aid to correct your condition.

There have been several threads just lately concerning fuel pumps acting very irratic. During your crank but no start condition, turn off key and depress the valve core in the schrader valve on the fuel rail to test for presence of fuel. A fuel pressure tester is ideal, if not available, just look for the presence of fuel.

Yes!! Always pull codes if the CEL or SES light is on!! I sometimes forget to mention that as a default "first thing to do ~ Always!" statement...

From what you are saying about having to hold the gas pedal down to get it to fire up doesn't sound like the CPS anymore ~ kinda... It seems you aren't getting spark, but the injectors are still firing... Once the system catches up, per se' you have all this fuel fouling everything up... That could be the CPS, but.... I'm pretty sure the fuel/air mapping comes more from the IATS on the bottom of the intake tube after the MAFS...

Take caution when checking for fuel pressure with the Schrader valve on the fuel rail... You will need a tiny screwdriver or allen wrench to get to the valve... If the system is working, it will have a good amount of pressure pushing fuel thru the small opening... The pressure will drop quickly, but the spray will hit the hood the first time you push the valve down...

Do you have a Check Engine Light (CEL) on?

Let us know so we can better assist you!!

Cheers!!

no CEL or SES lights on. :mad:

I will check for pressure in the rail the next time it happens, duh can't believe I didn't think to do that. If it would have been my old 76 bronco, I would have yanked the fuel line off the carb about 30 seconds after the first time it happened!

Thanks,