hey guys check this out.truck runs fine at 60 degress and higher.at 40-50 degress.it stalls.removed fuel filter.clean.replaced fuel pump module and the fuel rail presure sensor.temperary removed clean filter.install fuel presure tap.@ idle has 32 psi.push the brake pedal and the fuel presure drops to 0 and stalls.what du u guys think.

 

Subscribed... don't know why hitting the brake pedal would make the fuel pressure drop like that, maybe it's the other way round?

Some stalling issues with the '05-up V10s have been cured by cleaning the throttle body. There is no IAC, so any crud around the throttle body butterfly makes it act weird.

 

I cleaned the mass air flow sensor and throttle body's.had a fuel presure gauge connented.had my son put it in drive.and as he pressed the brake peddle.the fuel gauge goes to 0 psi and stalls.only does this when its 50 degress or cooler.

 

Any idea ford guys.this o5 f350 v10 is killing me.

 

When you cleaned MAF, did you reset the computer?

 

No i did not.was i supposed too.

 

Yes, its good to, to speed up the computers relearn of the clean parts. Any chance you lose power to the pump with the brakes on?

 

Ok thanks.last night i checked voltage to the new fuel pump module.13.7 volts.from the red wire to ground.i also cleaned all the ground therminals.this morning i started the truck.it is 39 degress.warmed it up.preseed on the brake to put it in drive.rpm dropped and stummbled.

 

Interesting thread/topic...subscribed.

Did you monitor fuel pump voltage before and during depression of brake pedal?

 

Well i was not able to locate the fuel pump wires.but i had the spare tire down and i checked it at the fuel pump moduel.my understanding is that the module ramps the variable speed fuel pump.i will check again tonight.but before pressing the brake it would be 13.7 as i pressed on the brake peddle it would drop to 13.2.thats not even 1 volt diffrence.this 05 v10 is killing me guys.please help.

 

Might it be vacuum related? Power brakes work on vacuum, and if theres a problem with vacuum system, that could likely be cause of stall/stumble.

 

Ok thanks for the reply.when i get home i will checked all vacuum lines.when i cleaned my throttle body.i did not see anylines disconnected.but maybe one of the lines might be leaking.

 

Ok thanks.last night i checked voltage to the new fuel pump module.13.7 volts.from the red wire to ground.i also cleaned all the ground therminals.this morning i started the truck.it is 39 degress.warmed it up.preseed on the brake to put it in drive.rpm dropped and stummbled.

 

Gfl good point.tonight when the temps drop.i will check too see if i lose voltage to the fuel pump module when i press on the brakes.thanks for your replies guys.trying to fix this truck

 

You have said twice that it stumbles after the brakes are applied and it is put into gear. I would be looking at the wiring from the motor being moved when the engine torques while going into gear. it sounds like you have a wire that is losing contact when the loom is contracted from the cold, and the torque of the trans shifts the motor around..........
just mu .02
Good Luck, Roger