Surging 7.3

[Jim Culver]

About 3 months ago (warmer weather) I bought a 2001 F-350 Crew Cab LB 7.3 Auto 4x4. From my experience with my '85 ATS turbo 6.9, I had the 7.3 muffler removed making it straight 3" exhaust. Other than a K&N type (panel) intake filter it's stock.

Since the cooler weather has begun (KS) after the engine has started just fine (idling) you begin to hear the waste gate opening and closing sounding like a 'blow torch' (not cool for the neighbors @ 6 AM). One I touched the accelerator it was fine for a little bit, then the cycle would start again. Once driven it was fine.

Now with the OAT in the 20 degree range it does the above plus the engine & truck surges (approx 200 RPM). Not good.

A chat with a local dealer mechanic suggested I might want to replace the Exhaust Back Pressure sensor (4C3Z-9J460-A, retail $138.00), I bought one but decide to write you guys before I swapped them out. The mech explained this sensor reads the pressure between the engine and the turbo, and didn't really think the muff removal was a big factor. He also said he did some other work on a truck that did the cycling but didn't surge and the customer didn't complain about it (it's muff was removed). A buddy who had a '99 that he had removed the muff on cycled like this.

Help, my fellow 7.3 brothers. Not gonna do this much longer.

 

[DaveBen]

The EBPS does this on almost all Ford diesel models. Yes, I would change it. Good Luck

Dave

 

[BBBxcursion]

Sounds like the valve opening and closing in the exhaust, which is normal for your truck. It's not the wastegate, there's another valve in the exhaust to help keep EGTs up and warm the engine up.

 

[Crumm]

When you change the sensor clean the tube that is attached to it. Normally the sensor is fine but the tube the runs from the exhaust manifold to the sensor becomes plugged with soot. You can use a piece of wire chucked up in a drill to clean it out or many guys find it easier to just replace the tube, they are cheap. Be sure to also clean the hole where it screws into the manifold.

 

[CSIPSD]

Sounds like the cold weather package, it will idle up and close the EBPV to build heat in the motor quicker. When you touch the brake it turns it off as if you were going to drive off, the EBPV will continue to open and close for as long as several miles depending on the temp. Sounds normal to me, but if it is surging when your driving, after warm up then you might have a issue.

 

[powerboatr]

agree with all the ebv is doing what its supposed to do int eh cold
it will do it driving to if its cold enough and your not on the throttle , like coasting to a stop
as for surging it will surge in cold weather at speeds between 35-40 depending on your gearset, when its warming up. the od locks in before teh truck is really ready and it will surge/buck some. try driving with OD off till she is warmed up and see if goes away.