Engine shuts down at operating temperature
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Engine shuts down at operating temperature
2003 f150 supercrew 4x4 5.4 216k miles - i know every situation is different but here is what happened to me and hopefully can help someone down the road. the truck started to hesitate as in no gas, then the motor would stop, leaving me with no power steering. the truck would start back up but just die again randomly at operating temperature.
i checked this forum and searched for everything in which it could possibly be. no codes thrown at this point. the engine would run fine again when cold, then die again once warm. remember, no codes. thought moisture in tank as i live in new york, put two bottles of heet in tank, truck still would cut off. replaced fuel filter, many times, that didn't work. replaced fuel pump, that didn't work. replaced a common issue which was the DFPE sensor, that didn't work. still no codes. now, i am only driving in the neighborhood so i don't get stranded as i have needed two tows back to the house. i cleaned the throttle body which surprisingly wasn't too gummed up and cleand MAF. i checked every vacuum line there is and didn't find anything that would cause a vacuum leak.
yesterday morning there is a loud knocking noise and now the service engine light is on along with the battery light. code p0320 is present in which at this time enough cycles of misfiring is now throwing a code. it could be low battery or alternator but those checked out fine. a short in the wiring harness or ignition/engine speed sensors. all are ok at this time. so what was the problem??? stupid me and another buddy of mine completely missed a warn belt tensioner - we just happened to hqve another buddy take a look and that was the first thing he checked when he heard the noise. the pulley was wobbling so bad that when we took it off, the bearings left inside and pulley completely fell apart. replaced tensioner and now the truck runs great again.
so, please do not over look the belt tensioner if you are having an issue such as mine. oh; getting back and tying in the engine warm shut off issue is that i suspect the belt was tight when cold but when the engine was up to operating temperature, the belt was warm and stretched causing the tensioner to bind up and stall the motor. crazy that sometimes the issue can be simple.
i checked this forum and searched for everything in which it could possibly be. no codes thrown at this point. the engine would run fine again when cold, then die again once warm. remember, no codes. thought moisture in tank as i live in new york, put two bottles of heet in tank, truck still would cut off. replaced fuel filter, many times, that didn't work. replaced fuel pump, that didn't work. replaced a common issue which was the DFPE sensor, that didn't work. still no codes. now, i am only driving in the neighborhood so i don't get stranded as i have needed two tows back to the house. i cleaned the throttle body which surprisingly wasn't too gummed up and cleand MAF. i checked every vacuum line there is and didn't find anything that would cause a vacuum leak.
yesterday morning there is a loud knocking noise and now the service engine light is on along with the battery light. code p0320 is present in which at this time enough cycles of misfiring is now throwing a code. it could be low battery or alternator but those checked out fine. a short in the wiring harness or ignition/engine speed sensors. all are ok at this time. so what was the problem??? stupid me and another buddy of mine completely missed a warn belt tensioner - we just happened to hqve another buddy take a look and that was the first thing he checked when he heard the noise. the pulley was wobbling so bad that when we took it off, the bearings left inside and pulley completely fell apart. replaced tensioner and now the truck runs great again.
so, please do not over look the belt tensioner if you are having an issue such as mine. oh; getting back and tying in the engine warm shut off issue is that i suspect the belt was tight when cold but when the engine was up to operating temperature, the belt was warm and stretched causing the tensioner to bind up and stall the motor. crazy that sometimes the issue can be simple.