NEED HELP

[powerstrokefan1]

i have a early 99 f350 making a screaching noise(from the exaust) when gas held at a steady position. it doesnt make any noise untill about 1400 rps and quits at about 2100. does this when i am driving and when its in neutral. wot it makes no noises and has no difference in power. took it to ford dealership where it stayed for a week...they said they fixed the problem...well they didnt any suggestions?

mods: hypermax chip straight pipe k&n air filter

[Southpaw]

Throwing any codes?

What did they supposedly fix?

I would definitely try and get some more info out of them. Did you pay for it?

[codysweat]

check the ebv could be functing improperly.

[Young-SC-Owner]

its your ebpv functioning in the cold

[b737drvr]

Sorry to be ignorant here fellas...what is "EBPV"...I am new to diesel truck ownership and new to the forum. Is the EBPV supposed to kick on and off until the truck warms up? I know I have been hearing what sounds like an air bleed-off, on-and-off, through the exhaust for the first 5-10 minutes when I drive the truck when it is cold (like in the single digits or teens). Is this normal? Seems to go away after driving for a while. I think I may be having the same issue as powerstrokefan1 is.

[Southpaw]

Yes that is most likely what you are hearing.

It is the Exhaust Back Pressure Valve

It closes to aid in engine warm up in cold temps. Once the truck warms up it stops. You can unplug it, or gut it completely if you don't like it. It does kill fuel milage if your driving while it activates or if it is sticking. Hit the brake and it will open again.

[b737drvr]

Yep...that's it. So do I understand correctly that the sound (like bleed air) is when the valve is open - or closed? And the gas mileage is degraded when the valve is open or closed?...Please clarify. Thanks.

[APlusLawnandTree]

fuel mileage drops drastically when the valve is in operation (when you here the air shooting out) if i am correct i believe it pretty much dumps your exhaust straight out bypassing the turbo therefor your turbo isnt being used which is why your fuel mileage goes down....i could be wrong but im trying to learn all this as well