Exhaust Pressure Control Valve Issue?

[skyrider4000]

Hello, I have a 99' PSD. The truck is having some issues. The symptoms occured overnight, and weren't gradual. I got four Diag. codes from a local shop. They are as follows:
P1670 EF feedback signal not detected.
P0478-Exhaust Pressure Control Valve High.
P1247-Turbo Boost pressure low.
P0340- Cam Position Sensor Fault.

The truck starts and idles fine. But when I start to accelerate, it is very slow and sluggish. I started by repalcing the Cam Pos. Sensor. I was told this is a common problem. Replacing this didn't help. Do these symptoms sound like an Exhaust Pressure Control Valve?? And if so, would it be better to replace it? Or to buy one of these aftermarket parts that bypasses the P0478 code?

Please help. Thanks!

[todd]

ebps delete from dfuser will fix it $39 shipped or you could try replacing the sensor aprox $70 could also try removing the sensor and cleaning it then cleaning the tube as well

[skyrider4000]

Thank you for the feedback. But does that symptom, the very, very sluggish performance, sound like an Exhaust Pressure Valve problem?

[todd]

i think it could dont know for sure but that could be causeing it to defuel due to thinking theres to much back presure just guessing though

[custom_nirvana]

try unplugging the ebpv, thats what alot of guys do. it wont harm your truck, it will just take your truck alittle longer to warm up.

[skyrider4000]

Thanks for the tip. I'm just learning about these problems and researching as I go. My question in regards to that tip is.... I understand there is a hose that leads to the pressure sensor that builds up with carbon. If I just unplug the EBPS wont that just be bypassing the problem and not fixing it?? What about the clogged up hose and sensor? Thanks!!

[custom_nirvana]

I would unplugg the ebps start it up and see if the problem goes away, if it does then i would see about cleaning the senser and such and stick it back and see. But i dont see it as bypassing the the problem because you dont have to have the ebpv in order for the truck to run.

[skyrider4000]

O.K. I'm going to spend some time on it on Wednesday on my day off. I'll post some info on what that does or doesn't do. Thanks for the help

[skyrider4000]

O.K. I unplugged the Exhaust Backpressure Sensor. It helped significantly from how the truck was running before. HOWEVER, it still didn't fix the problem completely. The truck is still a little bit sluggish. Help!

Does the fact that I unplugged the Sensor and performance improved mean that the problems are related to Exhaust Backpressure? Or that the tube leading to the sensor is clogged? Need more info. Thanks

[custom_nirvana]

once u have unpluged the senser if its clogged or not wouldnt make a difference becuase its not work anyways. but as for the sluggish part i have no idea.