Strange boost problem on my friends v70r

[andrewc1267]

Originally Posted by Derek UK

If he gets 6 and 13psi and your cars are the same, what numbers do you get?

Mine is physically the same car but mine isn't standard

[Shinsplintz 101]

All I know about ME7 cars is that the ECU is a barsteward to cheat - which historically has lead tuners and DIY boost junkies to favour the earlier ME 4.3 and 4.4 cars as they are much more forgiving to mods, rather than holding back the potential gains.

Maybe this has moved on in the last few years? Perhaps check out the US forums before chucking anymore time effort at flogging this particular horse.

[andrewc1267]

Originally Posted by Shinsplintz 101

All I know about ME7 cars is that the ECU is a barsteward to cheat - which historically has lead tuners and DIY boost junkies to favour the earlier ME 4.3 and 4.4 cars as they are much more forgiving to mods, rather than holding back the potential gains.

Maybe this has moved on in the last few years? Perhaps check out the US forums before chucking anymore time effort at flogging this particular horse.

The boost fault has not always been there it's a new fault the car ran faultless for years the MBC was only fitted to try and eliminate the waste gate control solenoid I have since put it back to standard and tried my WCS on it and the fault still exists

I have replaced all vac hoses I have removed and inspected all boost hoses I even replaced the 2 one way valves under the intake manifold as I had one fail on mine and the boost was filling the brake servo I have refitted all the boost hoses and smoke pro the whole intake system again and definitely no leaks I've also check the tank vent valve as again I had a fault with this on mine not closing properly but that only gave me mixture related FC

[andrewc1267]

We have no put his car back to standard and the boost issue is still there once all back together we did a full codecode sweep and code clear no codes came up a short road test and MIL on and code P0234 overboost condition I cleared the codes and drove again and code came back the car will not boost more than 6 psi on the gauge I have swapped out the gauge with mine and also ran a new vac pipe to it incase there was a leak has anyone any idea why I am getting an overboost code on a car that's not boosting properly

[Baffler]

Do both cars have a MAP sensor under the radiator trim/cover? If so try swapping yours to your mates car.

[andrewc1267]

The map sensor on both cars is in the intake pipe below the throttle body I've already tried swapping them and it makes no difference

[andrewc1267]

I have a development I have rescanned the car today and I have 2 codes one in the abs module relating to n/s/f wheel speed and one in the engine control module saying vehicle speed signal missing I believe that the me7 system is an on demand system so could make sense that it would need to know the road speed in order to calculate the boost delivery does anyone have any thoughts on this

[Baffler]

I guess you could try removing and cleaning the ABS module multiplug with some contact cleaner, let it dry out, replace and see if the signal is restored.

Some have had success, albeit temporary, with wedging a piece of cardboard between the multiplug and the module in order to keep pressure against any broken soldered joints on the module circuit board.

[andrewc1267]

If I get chance over the weekend I'll remove the abs module and resolder the pins I did about 5 years ago and don't remember it being that difficult

[andrewc1267]

We have decided to get rid of both cars under the scrappage scheme so fixing it is no longer an option