No boost

[vickyg]

Hi folks,
Took the 940 out today, didn't notice an issue on the way out (mostly downhill) but on the way home up a very steep hill it was clear I had no boost (turbo) - throttle had next to no effect and it wouldn't go over 2000-2500 rpm. Wait for a flat stretch and floored it, not a lot happened. Despite being 2.0l (auto) it usually has quite a kick. It gradually sped up but nothing interesting. I don't think the turbo is working. Not sure where to start on this one. I understand there is a wastegate rod that can come off? The boost gauge on the dash claims to be boosting - but it really isn't.

V

[vickyg]

Additionally my husband said the other morning going up a slow hill it stopped dead. He restarted and no problem after that.

[TonyS9]

If the gauge is showing boost then the turbo is probably working, I can't think of any reason to doubt it. When it fails it will usually stick or not register any boost.

My first thought is fuel pressure, especially if the rev counter is working. Try clamping off the return flow and seeing if it revs up in neutral.

[vickyg]

I haven't clamped off but know it revs well in neutral, no issue there. But under load it's lost any kind of performance. It's had a new pressure regulator and was going like a train. I'm a bit stumped.

[tofufi]

I'd check your wastegate isn't stuck first. On mine it is on the underside of the turbo...

When I had no boost, I had seized my turbo...

[TonyS9]

Originally Posted by vickyg

I haven't clamped off but know it revs well in neutral, no issue there. But under load it's lost any kind of performance. It's had a new pressure regulator and was going like a train. I'm a bit stumped.

That would tend to exclude fuel pressure regulator, but its always possible a new item goes faulty. If you can't measure pressure then you might have to run it clamped, it might upset the idle mixture and set off the emissions light.

Anyway I still think you have a lack of fuel, other reasons could be a faulty injector, faulty AMM, faulty fuel pump (1 of 2), blocked filter etc.

Have you tried to read any codes?

[vickyg]

No I've not played LED morse code yet as it's been raining stair rods here. Had it booked for tyres, decided to go and take it slow. Started juddering like mad under load so I drove OAP style to ATS. New tyres have transformed the ride but it's still gutless. Brimmed with super for the return home in the hope that might help, nope. It's had a new filter in last month and I tested both pumps during the "bad fuel" episode, I can also hear them both running. I kept the old regulator as there was nothing to say it failed, I just replaced due to age and the amount of water in fuel. Bear in mind it was boosting and driving great before and after MOT, this has suddenly happened after I thought I was in the clear

[TonyS9]

Ignition is also still possible, as a weak spark caused by distributor problems can get drowned out by fuel increases. You can usually apply the power slowly to get the rpms up, but being a manual helps.

I'm trying to think how weak spark comes across for this who might not know. but its pretty dependant on accelerator. Its very rough and random misses, to the point the engine can cut out entirely, but it will revive if you back off quickly enough. Lack of fuel will be smoother I think.

A video might help if a passenger could record it of course.

[vickyg]

It's also had new cap and leads, more tomorrow, if it stops raining...

[B10B]

Normally you get black smoke out of the exhaust and no performance if the turbo dies or you have a boost leak.
If no then you may well have a partial blockage in the exhaust which would cause exactly what you describe, gutless, not wanting to rev under load with pressure still recorded in intake manifold.
Easy to check if the exhaust gas is making it out of tailpipe with the car just sitting running.