Exhaust Backpressure System

[schoelta]

Can someone explain what this system is for, and the logic Ford uses to command it on and off? How does the the PCM know when to turn it on, and not to. What temperature is it supposed to kick on?

I'm asking because the other day the temp dropped to below 30 and it was turning on and off many times even with the engine was at normal operating temp. The gauge was between the O and R in NORMAL, which is where is usually stays, and it was turning on and off. While I was driving down the interstate, I could feel the truck losing power for a short time while it turned on.

However it seems when it's 30 or above, nothing happens, even when the engine is cold.

I would like to know if I have a problem or not. My truck is a 97 F250 PSD.

Thanks.

 

[lindstromjd]

The system is for heating up the engine by closing off an exhaust valve right behind the turbo. Makes the engine work harder to push out the exhaust gasses, and thus warms up quicker.

IMO, and probably everyone who drives a powerstroke, it's an unnecessary system. Unplug the thing and be happy with not having to worry about it anymore. It defaults to open.

 

[OLDBULL8]

The EPRS is on the front of the engine, it has a tube running down to the exhaust pipe, that pipe will get plugged up with soot or a hole rusted thru it. Needs to be cleaned or replaced also the sensor needs cleaning, the sensor has a diaphram in it, clean carefully.

 

[79jasper]

It uses the iat, engine temps, and throttle position.

What oldbull said can have a lot to do with it.

 

[94f450sd]

Unplug it and forget about it.better yet,gut it for lower exhaust temps.