hey guys i have a 97 e350 van 7.3 powerstroke 235,000 miles
rebuilt tranny, new fuel filter, and fuel pump. i have a strange problem
when the temp drops outside. when im driving the van at temp above
40 degrees its ok. when temp drops below 30 degrees i dont have much
power. when i press the accellerator pedal the engine does nothing at
first and it slowly picks up speed. it starts right up in the morning
at temps below 30 degrees and runs smooth . if i try and drive while cold
it has no power and smokes black badly for a few minutes. i did replace
the pcm with used one out of another van, same year ,model and engine.
the computer had one letter different. not sure where to start here

help please
thanks
steve n.carolina

 

Sounds like the EBPV (exhaust back pressure valve) is closing to assist in rapid warmup. It's quite normal, although annoying, when temps are 30 degrees or below. You can disable that function by unplugging the EBPV and the computer will ignore it and a lot of folks on here just leave it unplugged. The connector is a two wire plug located just in front and below the turbo, the only one there. Just unplug it and see if the problem goes away.

Here is a description on its function ...

Exhaust back pressure regulator is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. The PCM uses the measured exhaust back pressure, (ambient) intake air temperature, engine oil temperature and engine load to determine the desired exhaust back pressure. Valve position is controlled by switching the output signal circuit to 12 volts inside the PCM. On/off time is modulated from 0 to 99% dependent upon the exhaust back pressure desired.

Another thing you can try is drive it a few miles to get the engine oil temp up then shut it off and restart.

 

EBPV plug

 

thanks alot for the reply jim. never
had this problem before. i will try unplugging the valve
steve