URGENT Help Please. Boost Pressure sensor

Hi All,

Well just as sure as the night will follow the day, the night before my mum and dad are to take there new P38 i got them for christmas away on holiday, POP!

I had the car at mine for a couple of days to change the glow plugs as it was turning into a lazy starter, changed them not a problem, and the car was firing fine, then while driving it back to my mum and dads tonight, POP when i pulled away from the lights.

I pulled over and couldnt see anything wrong, drove the car and noticed that the turbo wasnt doing its job. Its really slugish... the guy next door but one has an auto diognostic so we put it on and its coming up Bust Pressure sensor, and the fault wont wipe off.

Ive got unitll 12pm tomorrow before i have a very disapointed mother, and a grump farther.

First of all, Am i right in thinking the pressure sensor is located on the bottom of the Cast Air inlet box? also has anyone had this? is it a new sensor?

Thanks Guys oh its a 1999 2.5 Turbo Diesel

Dont take the fault at face value, its much more likely that one of the hoses has popped off or split therfor the sensor is not reading any pressure so it thinks the sensors duff.

I'd go with Rewmers suggestion, sensors don't go POP but turbo hoses certainly do and as he says this would likely trigger a sensor fault.

But for what its worth the the MAP sensor (Manifold Absolute Pressure) is mounted on top of the diesel filter. There is a simple air hose going onto a nipple on the underside of the manifold. The sensor you are thinking of is likely the intake air temperature sensor.

Check it out on RAVE under Fuel System - BMW Diesel/Manifold Absolute Pressure

Well,

needless to say they didnt make it away in the car... its still on my drive lol..

I am a little further forward though. rewmer you were right!!! the hose had popped off, but after connecting it back up the fault code still wouldnt wipe off( 0133 Boost Pressure Sensor). So after a little more investigating ive found the problem.. and its a big one!

The Map Sensor - as Spud says! or rather the wiring. it apears the car has had a remap box fitted. http://www.psi-motorsport.com/turbodiesel/fiche.php?selectid=145

This invlves disconnecting the Map sensor, removing that part of the loom and replacing it with the loom supplied with the unit. The only problem is this has now bi-passed the MAP all together hence the car now reading it as a fault! :doh:

So i have to try and locate a section of this loom, fit it to the car so the fault code can be wiped, then refit the box (it does make quite a difference, so its staying) lol

Does anyone know of a 2.5 dse being broke anywhere?

thanks

Hmm, not sure about that. The older PSI boxes use the MAP sensor but not electrically, you cut into the air hose below the MAP sensor but other than that its a true plug in, no wires cut. I don't believe the newer ones cut into the MAP sensor at all. Post us a photo of the MAP sensor and we'll be able to tell more

SpudH said:

Hmm, not sure about that. The older PSI boxes use the MAP sensor but not electrically, you cut into the air hose below the MAP sensor but other than that its a true plug in, no wires cut. I don't believe the newer ones cut into the MAP sensor at all. Post us a photo of the MAP sensor and we'll be able to tell more

Click to expand...

the older p38 diesels use the hose type sensor,the later ones do use the loom for info.they do not use the hose which goes from underneath the manifold to the fuel filter housing.

I dont think any of the wires have been cut, just unpluged and taken out. There is nothing cut into any of hoses thats for sure.

the map sensor located on the top of the diesel fiter has just been unpluged and this PSI box pluged into that and then wired down to where the map senso loom went.

To make matters complicated, ive just spoken to a breakers down south, having talked to him for 15 mins or so, he said there was a boost pressure sensor on the side of the turbo and as the fault code was reading Boost Pressure sensor I should start there?

what do you all think?

drewsp38 said:

I dont think any of the wires have been cut, just unpluged and taken out. There is nothing cut into any of hoses thats for sure.

the map sensor located on the top of the diesel fiter has just been unpluged and this PSI box pluged into that and then wired down to where the map senso loom went.

To make matters complicated, ive just spoken to a breakers down south, having talked to him for 15 mins or so, he said there was a boost pressure sensor on the side of the turbo and as the fault code was reading Boost Pressure sensor I should start there?

what do you all think?

Click to expand...

That would be the boost pressure regulator on the side of the turbo. The diaphragm that opens the gate to bypass the turbo. This unit controls the maximum boost pressure.

thanks wammers, so with the fault reading boost pressure sensor, It mat be becasue of the MAP Sensor being wired through the PSI Motorsport box. Well ive had no luck finding one being broken, all that are advertised on ebay have had there wires cut when the engines had been removed. So looks like a trip to main stealer on monday, Better have the cream lol