Petrol Turbo diagnostics

[Col]

it should weigh less than the backbox I would say...

but that's only based on handling cats on other cars, so I may well be completely wrong

[mjb]

cool, cheers

[mjb]

It would seem that the coppers don't like it when you're driving around in a battered 406 with an oxygen sensor sized hole in the exhaust and a boost gauge loose on the dashboard...

"Is this your car?"
"no" (crap)

Thankfully I do have the owners permission, he does have it insured, and my insurance does cover me to drive it! Also very thankful the coppers accepted my story about just taking it round the block to diagnose a problem, and gave me an escort home. Got a right bollocking though

Anyhow... with the oxygen sensor detached, I got no near-stalls when stabbing the throttle from idle (so it IS restricting the airflow) however still no boost. Exactly the same - 1psi vacuum That's even with the dump valve disconnected and wastegate solenoid bypassed

So I think I'm still left with just two possibilities:
1. Knackered turbo
2. Gaping hole in the intercooler

[totaleclipse]

could it be a seized actuator?

seen that on T series rover turbos (T25)

skoosh of wd40 and some manual manipulation sorted it out.

[mjb]

which actuator, the wastegate? That's under a lot of pressure but there's a VERY definitive SNAP to it closing when worked by hand

[jasper5]

Have you actually checked the turbo/intercooler piping for splits? They don't always make a noise when they split.
Have you taken off the pipe at the turbo and checked by hand to see if the turbo blades turn?

[mjb]

No, and no. Not yet. What's the best way to check the hoses and intercooler? bathtub?

[jasper5]

The professional way of checking for leaks is to use a "Smoke Pro" this a device that fills the system with smoke under pressure, leaks will allow the smoke to sneak out, and being visible, can easily be pinpointed.
My way of checking the pipes is to remove them and squeeze them and look for splits, I guess sticking the intercooler in the bath is as good a test as anything, but compressed air might be a good idea.
I asked a mate if he had come across your problem, he said he had one a while back which turned out to be a split hose, on the left side?

I once read of a fault with an intercooler where the seams at the sides opened up on revving the engine, causing lack of boost.