I have a 97 F250 HD 4x4 7.3L.Here's my problem.,I have almost no power, unless I let it warm up for 30 minutes.When I go to take off,I have to floorboard the accelerator to go with any authority.It feels like a brake is dragging or I'm in 2nd gear.When I accelerate, the truck feels like it down shifts and takes off.After about 15 minutes of run time,it's fine.The truck starts and run fine.Thanks for any advice.Rick.

 

Here's where I'm at.I removed the tube running from the exhaust manifold to the exhaust back pressure sensor(I think that's what it's called).It had a slight build up off carbon.I went ahead and cleaned it.Tried to remove the sensor,but it is really tight and I didn't want to break anything so I left it alone.I still have the same symptoms.I disconnected the actuator plug by the turbo.Same thing.The valve itself is working,I think,It sounds to me I may have a bad sensor or the valve sticks until it gets good and hot.Any inputs?

 

Some power application 'delay' is normal in cold temps on the 7.3..

The valve operation is to help heat the engine coolant and raise cabin temps quicker..

As soon as you launch, the power should come on within a few seconds or more unless extreme cold temps....

The exhaust back pressure valve is controlled by the PCM.. The PCM reads the EOT (engine oil temp) and the IAT (intake air temp) as well as the exhaust pressure in the right exhaust manifold for valve operation for cold startup.. If the tube plugs, or the sensor is out of range, most times you'll get a CEL/DTC.. Since this seems to follow a warming pattern, chances are the valve isn't hanging.. What would really help would be to have it scanned/data stream pids checked for correct sensor PCM imputs at/for correct temps.. The backpressure sensors are pricey, and a data scan would tell you if its working OK without disturbing it.. If you can read the data info. it'll at least point you in a direction, or tell you what its not in most cases..The system will default to open, if the sensor/circuit fails.. Or should.. But out of range imputs may command the valve to close on a warmer engine..

 

Thanks,It sounds like I'm off to the dealer.Boy I was trying to avoid that.

 

It may not be that bad..

So,, when your suffering from extended power loss, do you hear a consistant 'hissing' as well? indicating a closed/stuck valve.. Have you verified the valve is closed during warm up or on a heated engine? Open is with the valves tang on the bell crank against the casting stop, and the arm retracted.. Certainly sounds like a EBV issue, especially when you say it feels like a 'downshift' and the truck gains back it power.. On an accell, the EPR should be deactivated allowing for an open valve...

 

another big problem with the 7.3 is the under the valve cover looms come disconnected and will wipe out entire banks, all you have to do is pull the valve covers and check to see if one has come disconnected, is so they sell an update kit that isn't saposed to come apart

 

you can unplug your EBPV to see if that is the problem. there is a plug in front and a little to the right of the turbo. It is the only two wire plug. Try unpluging that and see if it fixes your problem. It will take a little longer for your truck to warm up with it unpluged, but your truck will run fine. I have had mine unpluged for quite awhile.

 

What is the actual name of the sensor on the front of the motor by the water pump? I unplugged mine and the problem you described went away. The air intake sensor is fine. I asked the dealer to check out the problem last week when the fuel heater shorted and left me on the side of the road but they didn't. Guess they need another hour of diagnostic, wouldn't want to fix two problems at once! Does that pipe plug up often?

Nate
99 F350 7.3L

 

EBP..

Exhaust Back Pressure...

 

im having a very similar problem . i have a 97 7.3L f250 while driving or sitting still i heard a noise coming from the front of the truck , almost sounded like a jake brake on a big rig .while in motion i accelerate & it would go away .until i leveled out at around 1000 - 2000 rpm then the noise would come back or if i just let off the gas i would hear it . if in neutral sitting still i bring the rpm up to about 1500 the noise will a peer & the motor will bog down to about 1100 - 1200 rpm . with the passenger door open , i noticed that while this was happening there was a loud hissing sound from the tail pipe . i cleaned the tube as well & i still hear the noise . i will now unplug the EBPR to see if that is the problem .