Boost Pressure Too Low - Any Advice Appreciated

bluegnat2000 · Post by **bluegnat2000** » Tue Mar 27, 2007 8:22 pm

If I go over about 75 MPH in my HDI 110 est the engine management light comes on. Its been on a computer at the local garage and it comes up as ECU fault P0246 Boost Pressure Too Low. The car then wont go over 3000 revs when this happens. Once its reset its fine until I go over this speed again !!

The garage is only my local small place and he's going to look into it but does anyone have any idea what it might be and how much ??

Its a 2000 model with 150000 on the clock, I love the car but if its going to start costing me lots of cash I'll be thinking of trading it in.

Its recently had a new cluch and flywheel so I'm noy sure if this has anything to do with it.

Any help would be appreciated.

Thanks

Benner · Post by **Benner** » Tue Mar 27, 2007 8:31 pm

Dont go asking any coppers for any suggestions will you!?!

mjb · Post by **mjb** » Tue Mar 27, 2007 9:09 pm

Be glad the diagnostic output matches the trigger of the fault!

Could be something simple like a rotted pipe or something, but I don't know much about this side of things I'm afraid. A few drops of water and a zero-g vacuum would be useful to troubleshooting I imagine...

niz406 · Post by **niz406** » Wed Mar 28, 2007 12:43 am

Wastegate Control Solinoid... its the sensor responsible for your problem identification!

I reckon it will be the actuator feed hose ( leak ) or the actuator on the turbo itself.. and the result is that the wastegate doesn't open and the turbo continues to boost! Get it sorted sooner rather than later, especially on a HDi

jameslxdt · Post by **jameslxdt** » Wed Mar 28, 2007 7:23 pm

niz as the fault is boost pressure too low its not so critical as if it was too high
could be an air mass meter, the ecu measures the volume of air Vs. boost pressure, so if it see's a normal flow of volume but boost pressure that it thinks is outside of parameter compared the flow of air then it will flag the boost sensor, when the actuall part at fault is the air mass meter feeding the ecu with faulty information, check all hoses though, as well as the intercooler, could also be a leaky vacuum pump or brake servo as the pump supplys the soleniod with vacuum as well as the brake servo

niz406 · Post by **niz406** » Wed Mar 28, 2007 7:41 pm

whoops teaches me for not reading the bloody title.... I thought it was over boosting !

bluegnat2000 · Post by **bluegnat2000** » Wed Mar 28, 2007 7:51 pm

Thanks so far guys. I forgot to say earlier that I've recently had a new crankshaft sensor fitted. Could this be connected to the problem somehow ????

Cheers

jameslxdt · Post by **jameslxdt** » Wed Mar 28, 2007 7:58 pm

possibly but im going to say no, the hdi 110 does have mapped boost pressure, but does have a pressure sensor also, but if the boost is, say for example, 0.5 bar at 3000rpm and WOT, when it should be 0.9 bar at 3000rpm and WOT, but the engine is actually at 4000rpm and the crank angle sensor isnt reading correctly, then it will flag boost pressure too low as the turbo simply cant produce 0.9 bar at what it thinks is 3000 rpm as its at 4000 rpm in reality and there is too much exhaust gas and the turbo simply stalls

bluegnat2000 · Post by **bluegnat2000** » Wed Mar 28, 2007 8:32 pm

Thanks James

Do you think my local garage will be able to sort this out or would I need to take it to a tuning specialist ?

Any idea how much it'll cost me ?

Thanks

jameslxdt · Post by **jameslxdt** » Wed Mar 28, 2007 8:35 pm

depends if your local garage has even the first idea about how a HDi works!
more often than not your average garage doesnt have a clue about diesel engines, i would guess to find the fault you could be looking at anything upto £150+vat+repair+parts

niz406 · Post by **niz406** » Wed Mar 28, 2007 9:03 pm

jameslxdt wrote:there is too much exhaust gas and the turbo simply stalls

Turbo should only stall if there is too much back pressure on the compressor side, not the turbine side

jameslxdt · Post by **jameslxdt** » Wed Mar 28, 2007 9:05 pm

well ok, but do you know what i mean though?