Well I have a 2008 f450 6.4, deleted dpf and egr running a H&S tuner. it has a strange habit of not running when cold. It will start 90 percent of the time first try, if not on the third when cold say 40 and below but will start, but will shut off randomly keep in mind all this only happens when cold.... after starting I will let it warm up say 5 min then off to work. It will cut out sometimes one or twice??? but one the truck is up to normal temp on the gauge no problems at all runs awesome . the other day started normal no issues was 30 out side drove to work ran fine, went to lunch started cold out side 28. no warm up just go. died 2 times just shut off started back up no problem just like some one turned the key off. has done this twice. It will buck going down the freeway when cold. All this and NO codes I have replaced fuel filters seemed to help short term maybe? have replaced the map sensor and the ebp sensor and it was full on condensation. any ideas? almost acts like my 7.3 when the cps was going out. I think it must be electrical because when it dies it will start back up no problem. Sorry for the long post. Thanks

 

Speak with H&S at all about this?

 

Yes they said the tune version I have should be good. there was a older tune that was a problem. So Still at a loss.

 

Problem solved ..... Bad Lift pump

 

Interesting..how did you finally determine the cause? Did it quit entirely?

 

OK.. guess what trouble is back? I drove it for 2 days ran perfect then today it quit at a stop, and the cut out down the freeway, then it acted like it lost some power and it would come back?? got home shut it off came back out like half hour later runs great again... I think it must be fuel related ? something in the tank? or the pump shutting off but makes no sense it does it when its cold mostly. I re tuned the truck tonight just to be sure. I also moved the fuel relay with another one. so the hunt continues??
Any ideas

 

I don't know if it is related to your 6.4, but my 6.0 has the same problem and it started right after I removed the EGR and EGR cooler. Good luck

 

Sorry I haven't got back to you on this... still being really random cleaned the IAT#2 on the manifold was really dirty seemed to help I think.. we have been watching it on the scanner and everything seems fine. I have let it idle and unplugged every sensor while it was doing the surging idle with no real change. I have tested the HPFP for shorts nothing. reloaded the tune updated firmware and cleaned the IAT drove it today so far so good but we will see how the rest of the day goes. we are out of ideas here and H&S is NO Help at all they say is its not our tuner so what ever... any more thoughts ... Thanks

 

What tuner are you using ?? I still think it might be tuner related..

 

Maybe the lift pump is just weak?
I think they have thermal shut offs on them, (I THINK), so theoretically, it would be running harder when the fuel is cold and thicker ?!
Maybe it's overheating because it's weak?

But then again, if that was the case, it should trigger an engine light from low fuel pressure....

 

And also, the HPFP on some 2008 6.4's had an issue with the wires going into the HPFP, they would wear, and short out intermittently.
They fixed it by adding a cable loom over the wires in that spot.

A friend had this happen to his 6.4.

 

Correct but he is not blowing fuse 74 so that is not it.

 

Edge platinum

 

I have a new lift pump on it and have tested the wire loom on the HPFP its good also no blown fuse as stated above. I believe it is electrical at this point just not sure what?? I still think 5 gallons of gas and a match would fix it but at this point its a challenge. here is a list of what has been done or checked

New lift pump
New filters
Tank pulled and checked
Fuel lines blown out
EBP sensor replaced
Map sensor replaced
Maf sensor cleaned
HPFP gasket checked for short - good
Crank sensor checked - good
Cam sensor checked - good
Fuel pressures, High Pressure checked - good
IAT #2 sensor cleaned - was dirty
All connectors ??? checked I will go over these again.
Changed out Lift pump Relay

some more symptoms ... when it will not start I have reloaded the tune and it will start
When it dies the lift pump will still be running and no fuel to Schrader valve by the fuel cooler .. so that is interesting but some times there is fuel there..so VCV or low pressure sensor on HPFP ?? the tech is saying when it is dying the truck is shutting the fuel off he thinks. when this happens if you turn the key off and turn it back on it will start. so maybe the computer ?

It will idle rough and low like 500 rpm then die it will start back up and run fine. when it does this there is fuel ant the valve by the fuel cooler and pressures are fine?

It will cut out when driving like someone turned the key off and come right back on.

it will run down the freeway at 75 and just cut back on power and the come back on say 30 seconds.

It will run fine in the morning and not restart 4 hours later?

sorry for the long post.. any ideas would be a help, I have already thought of driving it off a cliff

 

HAve you watched or logged the fuel pressure while that happens?