05 VOLVO truck VED D12 engine lacks power and makes 4mpg.. what is wrong?

Test your turbo boost response. Small leak will affect power and mpg even when its not detected on diagnostics. Pay close attention on turbo cooler right in the lower middle section where its open to road debries. The old soap spray method works best but you need a second person to pump and release the gas pedal repeatedly

 

do you have any egr codes or any fault codes, also check boost system for leaks make sure nothing is leaking

 

I will try to check boost systems for leaks and check for any codes. Last time i looked there weren't any fault or egr codes.

 

they are always black because they add it after they paint it so the boost sensor could well be faulty

 

Fuel primer pump and sensor

 

In there theres a fuel sensor and a fuel primer pump lift fuel in to the main fuel pump in front

Having the same deal

Going to change it tomorow

 

So are you saying that if this pump not working from the switch in your cabin I might have power issue?

 

Ugh, I have the same question and he never came back to say what happened I'm curious if that electric pump could be causing the issue...

 

Did you ever figure out the problem?