No power

[Groomzybanshee]

A buddy has a 08 6.4 H&s dpf egr delete. He was drivin down the road the truck cut out and acts like it hit a rev limiter now. Truck builds 0 boost also rail pressure says its 28.9 at idle. Change the pressure sensor in the fuel rail no change it has p0193 p0642 p0069 codes

 

[907DAVE]

Its probably a VREF (5V) problem.

Check wiring for shorts/ chafing on EPS, FRP, MAP and EGR sensors. Check the blue wire on the FRP for 5V with it plugged in, if its low disconnect the sensor to see if it returns. Repeat this on the Green/ Violet wire on the EGR, EPS and MAP.



If the VREF is high, that would indicate a possible PCM ground issue.

 

[White_monster]

Hpfp harness probably grounded out. This is why ford updated the harness. It's fairly common on the 08 trucks.

 

[Groomzybanshee]

Green violet on map sensor only reads .363volts

 

[907DAVE]

There you go. Start unplugging those sensors one by one to see if it returns. If it does replace that sensor.

If it does not return look for a wiring problem between the sensors and PCM.

 

[Groomzybanshee]

Ebp sensor

 

[907DAVE]

VREF came back when disconnected?

 

[Groomzybanshee]

Yes we unplugged the sensor it read 5 volts. Plugged sensor back in it still reads 5 volts and runs fine. Going to change sensor anyways

 

[907DAVE]

Good idea. Glad you got it narrowed down.