Hi Everyone

Im living in South Africa Cape Town, and struggle with my 2.8 CRD Cherokee(Liberty) with an overboost problem. I tried nearly everything. All the sensors like the MAP sensor/Speed sensor/vacuum reservoir were replaced. I did the EGR and I also replaced all the injectors with new ones. I also cleaned the whole fuel sistem.

The only other option is now to replace the turbo, or the computer of the car. The overboost only occur under 2000rpm. It also only occur when you drive light foot. Is it maybe the that the vains of the turbo do not pitch back fast enough and therefore keeping the boost higher than what it should be, or is it the computer that interperet the signals from the Map sensor wrong?

I would appreciate any help becuase this whole exercise cost me a lot of money so far.

Regards

Capetown

there is a way to manually moce the vanes to make sure they
are not getting hung up in a position...

that would be my first course of action... i am sure someone will
chine in to where this rod or what ever is in the engine bay.

_________________
Trevor

'05 Limited CRD Inferno Red Pearl Coat
Home made provent installed @ 35443, SEGR installed @ 35466, Fumoto valve @ 37500, trans and transfer case skid, In tank pump installed @ 43500, Suncoast TC & Transgo Shift Kit @ 44730, EGT, Boost, Trans temp gauges, Samco hoses, Rebuilt Trans w/ HD454RFE kit @ 56K, Inmotion Stage 2 @ 56K

It sounds like a problem with the turbo control actuator. There have been some problems with soot building up on the control arm in some vehicles using the same VGT style of turbo. The problem is often fixed by driving WOT once or twice on every tank so that all of the soot gets blown out and the arm archives full extension to rub the deposits off. It has been discovered that driving the VWs with VGTs very gently for fuel mileage is not good for them. using this have had this problem when I used to high of a percentage of waste motor oil for fuel. A can of Seafoam brand (or whatever it's equivalent is in Cape Town) fuel system will get every thing shiny clean.

_________________
Manure green 2005 CRD sport4x4, GDE Hot tune, Cat Gut, OE skids, Draw tight hitch, Duramax lift pump, 160K on multiple varieties of fuel, XM radio, Escort live with Redline, fog light mod, GPS, Icom IC7000 all band radio call sign KC9QPF, Grabber AT2s on Soft 8s, FIA grill blanket.

Capetown,

What year is your KJ? If it has the VGT turbo, look for the vacuum actuator on the top of the turbo (facing the hood), there will be a vacuum line running off of it to a modulator on the passenger side inner wheelhouse. If you're sitting still and rev the engine, you should see the rod coming from the actuator move. If it doesn't, either the actuator is bad or the modulator is. If you disconnect the rod from the linkage on the turbo, you should be able to move the lever coming off the turbo by hand if it's not frozen.

If your KJ is 04 or older, then most likely the boost reference line that connects to the wastegate is cracked or fell off, or the lesser-likely scenario is that the wastegate is stuck.

Let us know what you find!

The equivalent product in SA is to use Wynn's injector cleaner. I started using this recently in my CRD and seems to be working okay, time will tell.

Can you explain more about WOT i see it appearing on the forums but
don't understand the gist of it.

_________________
06 CRD LTD ( Euro )

WOT = wide open throttle.

Pedal to the metal... you know

_________________
L.O.S.T forever!
Silver 2002 Skoda Fabia TDI, 235,000km
Former car: Jeep KJ 2003 CRD

DIESEL - saving millions of liters of petrol every day!

That's the only way i know how to drive her so i should be fine

Thanks for clarifying, thought it had something to do with the turbo
but then i'm only a " newbie" learning..

_________________
06 CRD LTD ( Euro )

I have the same problem with my wife's '05. It's had 2 turbos, map sensor, actuator, and computer replaced under warranty and we still get the same P0234 overboost code. I'm kind of at wits end with it and don't know what to do next. the dealer has given up. I'm real interested in any advice or what you find with yours. Tia, Tigafila

_________________
'05 CRD Limited: 174k mi Euro Torque Converter, EHM, ORM, Racor fuel filter, Original Rocker Arms, Amsoil everywhere
'98 Dodge Ram 2500 Cummins 24 valve extended cab short bed
'01 Jinma 4wd diesel tractor

an after thought to my earlier post....

what about the boost selenoid filter? check that...

it is behind the airbox a tiny little thing.. maybe that is clogged

_________________
Trevor

'05 Limited CRD Inferno Red Pearl Coat
Home made provent installed @ 35443, SEGR installed @ 35466, Fumoto valve @ 37500, trans and transfer case skid, In tank pump installed @ 43500, Suncoast TC & Transgo Shift Kit @ 44730, EGT, Boost, Trans temp gauges, Samco hoses, Rebuilt Trans w/ HD454RFE kit @ 56K, Inmotion Stage 2 @ 56K