Turbo issues

[The Badger]

So on my way home the other day, besides the one of the wheel bearings breaking, the turbo has stopped kicking in? I have a pressure gauge fitted off the turbo and there is pressure there, but it now sits at around the same pressure with small fluctuation. It has stopped going to one and over when the revs go high.

So, taken the wheel, hub, stub off, and a little bit of metal from the rear oil seal on the stub had broken off and gotten stuck between the stub and the half shaft, which meant I had to mess about with jacks to get the stub off the half shaft out... And looking at the turbo, whilst waiting for parts to show up.

I noticed oil coming from the back of the alternator, of the thing (vacuum pump I think) that is connected to the vacuum servo on the breaks, oil is seeping from the area at the top of the return pipe that goes back to oil sump. So could that pump effect the turbo, or could the turbo could have just broken too?

Anyhow, thanks in advance for any help.

[TSD]

The vacuum pump doesn't have an oil supply as such, it breathes out via that pipe into the crankcase.

So it might be related to your turbo problem, but I don't think it is the cause.

If there is boost but it doesn't change much, check the small pipe from the turbo to the fuel pump. A leak there will still show some boost at the turbo, but it won't climb much as there no extra fuelling added under boost.

Check the diaphragm and plunger on the fuel pump isn't broken or stuck.

Also check the boost actuator on the turbo can move against the spring - mine has stuck once with interesting effects... loadsaboost and the Ibex went really well

[The Badger]

Great tips, will have a peek.

Ok, so a leak from the breather pipe of the vacuum might be due to over pressure? (possibly)

I have bypassed the mechanical fuel pump with an electric one, but it still could be leaking from where the fuel gets fed into the turbo, can look (it's a 2.8 TGV so the fuel come from the injector I think, I know it's not off the pump). Don't know how to check the boost actuator moving, never taken it apart, but I am guessing I need to take a pipe off and push something.

[TSD]

The actuator goes into the turbo on a small crank arm. The actuator pushes on it when there is boost. Just take a long screwdriver and push on the cranked end and make sure it moves with spring pressure pushing back. Mine has sometimes stuck after a long time standing idle.

Your electric pump knows nothing about boost, all it does is try to keep the injection pump full of fuel.

The thin pipe feeds boost pressure from the turbo to the injection pump, not the lift pump.

[The Badger]

Great, will look, yep, I was thinking where is the pipe off the fuel pump, but I still am learning about the workings of the diesel engine. (while they last)

Thanks

[The Badger]

Turbo update, turns out there was a leak in the pipe going to the turbo gauge, so I guess air was getting in there too.

The pipe going from the turbo to the fuel injector, I had a little plastic T piece in there and the T out to the gauge, where it was under the clip had broken almost off. As it just broken off when I touched it, the moral of the story is always use copper, or brass bits...

[TSD]

Glad you found and fixed the problem.

Could be worse, at least loosing boost is only inconvenient. On my old Disco, the previous owner put a low quality plastic joint in the cooling system, which blew apart under load.