Vectra turbo problem

[Bobblehat]

Anyone got any ideas about this, its for a mate of mine

Vauxhall Vectra Diesel (workhorse) when at high speed or under stress the engine management light comes on and the turbo cuts out. If he slows, turns off the engine and then back on again the turbo works again. Its recently had a couple of airflow meters put on, as it was thought this was the problem, but it has failed to cure it.

 

[Ferrari Spider]

it sounds like a problem with the turbo and specifically the pressure relief valve i believe it is called.  Had a similar problem on my saab.  in effect what is happening as you demand more power from the engine, the turbo spins up and rather than staying within its safe operating limits the valve doesn't operate and the failsafe then cuts in, dumping all the turbo pressure in one go.  is it like running into a wall, ie all power lost v. quickly?  if it is then this may be the cause.

it cost £80 to have it fixed.

[Nobby Diesel]

This sounds like a problem I am getting with my Audi A6. The slightest hill results in a dramatic loss of power.
I'll get it checked.
Thanks guys.

[smokie]

Blatant plug for another site which I moderate (and which is much more stringent than this one). (You'll recognise me when you get there - same ID!)

Go to http://www.honestjohn.co.uk/forum/index.htm, create yourself a logon ID and post the query in the Technical section. You should also try a Forum Search there.

There are some people who really know their stuff there. (The Discussion section is also quite entertaining, albeit there are some real pedants there)

[Ferrari Spider]

it goes without saying, clean fresh good grade engine oil is a must with turbo boosted engines, short change yourself on this, at best a new turbo, at worst a new engine.

[Bobblehat]

Thank you for your help Ferrari Spider. Info passed on.

Will have a look at the "honest john" site too, ta for that Smokie

[Lorry]

Another possibility is a partially blocked fuel filter.  The engine runs fine around town, but when you open it up it dies.  It then runs normally as the fuel has had time to get through the filter.

I take it that this is electronic injection.  The fuel starvation theory should still hold good, unless you can hear the dump valve operating.  Good luck!

[Canada Phil]

Hi Bobblehat, Sounds like a field day for the armchair mechanics All sorts of good suggestions so far. The relief valve you speak of is also called a Wastegate. ( a waste of good boost ) The blocked fuel symtems might also be lack of fuel pressure from the injector pump.
If unleaded or what ever your term is for lead free fuel the catalytic converter ( catalyzer) may be plugged.
Nobby is the A6 Old like me because I too have difficulty on the hills
If it has Tits or Wheels it will give you problems.
Canada Phil

[Nobby Diesel]

Phil,
Yes, it's a '98 1.9 TDi with around 135k on the clock.
Should be capable of at least double that mileage without real problems.

It's getting worse though, so it's off to the dealership soon. I tried a local independant mechanic, but the management system wouldn't communicate with the Snap-On diagnostic he was using.

I don't like the hourly rates at my local Audi dealer - something like £110 per hour. So I think I'll get it diagnosed and then fixed (if economical) elsewhere.

[Nobby Diesel]

Done a little more investigating.

It seems that there is a common fault with something called a MAF sensor.
Might be worth looking into.

[Matt Harper]

MAF (Mass Air Flow) sensor measures air density in the throttle plenum - very unlikely that this is the issue as it only controls fuel mixture.
I too would be suspicious of the pressure release valve (pop-off, wastegate etc).
This component is controlled by the ECU (i.e. it's electronic, rather than mechanical)
I'm guessing you need either/and a new actuator, pressure sensor or valve body. Hopefully not an ECU. A GM diagnostic will reveal the relevant trouble-code(s)
This car doesn't have a Hypertech chip in the ECU does it? 

[Lorry]

Scary isn't it.

Do all turbo diesels have dump valves?  Only I could never find one on my old Peugeot.

[BigH]

Holy Motherf*****Theresa!!
Nobby, you don't want to be hanging around mate. As I understand it, if you've got a blocked wastegate, then it's only a matter of time before your valve pops right the hell off. A man I know was unlucky enough to have both a blocked wastegate and a stuck pop-off valve at the same time, and that's a world you don't want to be on, I promise you. When his system finally reached a critical point of over pressurisation, he found himself in terrible trouble. I can still remember seeing his eyeballs rocketting in formation over the rooftops of the street opposite.

I think the moral of the story is to keep your pressure relief pop off valve in top working order, and there's various lubes that are just the job, as I say, it's imperative that your circuit can be freely vented.

You may want to consider fitting a breathing circuit via some large diameter surgical tubing, although for sweet Marys own sake don't let the pressure in the breathing circuit rise above the systems internal pressure, or there could be some very embarrassing blow-back.

I speak from personal experience of these matters, and I hope this has been some help. (of course you could just hit it with a hammer, or, as matron used to do, touch the end with a very hot teaspoon)
Regards
H

[Nobby Diesel]

Good grief!
In a last ditch attempt to avoid over pressurising my self, I'm off skiing for a few days.

If you lot sort all this diesel rubbish out, let me know.

Ta Ta.

[Martini...LB]

Holy Motherf*****Theresa!!
Nobby, you don't want to be hanging around mate. As I understand it, if you've got a blocked wastegate, then it's only a matter of time before your valve pops right the hell off. A man I know was unlucky enough to have both a blocked wastegate and a stuck pop-off valve at the same time, and that's a world you don't want to be on, I promise you.

I am sure I remember reading about your dump valve going off on another thread.

Martini