I am going MAD...... Can anyone help

I having been having the "charge pressure control - negative deviation, intermittent" fault for so long now.

Symptoms: Poor, rough acceleration. Can bearly accelerate to 3000 rpms without going to limp mode.

Attempted Cure: Changed 3 MAFs, 2 MAPs, 2 N75, complete pipework from turbo to IM including a new intercooler, stripped out and cleaned turbo. Cleaned out IM.

I did get some improvement following the pipework change but nothing compared to how it used to be. I used to have a lot of Black smoke before the pipe change. That is gone now, so I know there is no leak. I even had compressed air pumped into the pipework to look for leaks so I am sure I dont have air leaks.

Can any one point me in the right direction before I go mad. I miss my old baby

have you changed the vacuum lines to?

fotodaddy said:

I having been having the "charge pressure control - negative deviation, intermittent" fault for so long now.

Can any one point me in the right direction before I go mad. I miss my old baby

Click to expand...

Have you reset your memory and retested your vehicle to see if the same DTC comes back on since the last repair ?

If so, what are your freeze data log info? and the "P" code?

This info will allow us to point you in the right direction.

Leigh-Anne
JSP

I think there is a possibility that your car has a leak.

Leigh-Anne, I have wiped out the memeory (cleared the fault codes) so many times but it just keeps coming back.

I have changed all the vacuum lines!!!

I will scan the car again and get the P-Codes but what is the "freeze data log" info???

Thanks

You've confirmed full range of motion on the vacuum actuator with a mity vac? If it does move thru the range of motion, it holds the vacuum?

fotodaddy said:

what is the "freeze data log" info???

Click to expand...

Any time a 'P' code is logged there will be data that will be logged at the time that the fault (DTC) occured. This info helps to diagnosis the problem or help reproduce the fault - from this infomation it makes it easier to trace and repair the concern.

This freeze data may contain info such as vehicle coolant temp, vehicle speed, throttle position, boost pressure, intake air temp, ect ect

You can use a generic ODB II reader to obtain this info (such as a MAC ET9640 professional hand scan tool or something equivalent) Vag-Com also has this capability on the OBD II reader section.





Select OBD II

Then on the following screen select MODE TWO (and you should see something simliar to what is seen below)




For more infomation on this feature go to this website:

http://www.ross-tech.com/vag-com/tour/obd-2.html

Update FYI. Thanks to everyone who tried to help.

The problems all dissappeared with a new air-filter and fuel . Its a surprise that the air-filter got so bad in so short a time (last one was changed less than 2000K ago during the oil change service). but now my baby is back and I really enjoy leaving everone behind to eat my diesel particulates.