Boost pressure sensor?

[phil13]

After watching a you tube video , where the engine mount pipe is removed from the control valve(just in front of air box) They say that you will have vacuum at that point on tickover , but when the revs rise above 1k it dumps the vacuum to the mounts ? I have put on a vacuum guage on the valve and when I start the engine the vacuum rate slowly rises and when I Rev the engine the vacuum remains . When I turn of the engine it takes 3-4 mins for the vacuum to drop. Would anything else cause this ? And can it be bypassed to try it?
Cheers Phil

[phil13]

Ok , cancel the last post, turns out my guage was faulty, tried another and the vacuum control valve seems to be working as it should. I have ordered a hand pump vacuum tester so I can check pipes ect for splits or holes
Cheers Phil

[gmonag]

When you get the test pump, attach it to the tube that goes directly to the turbo VNT actuator, after the TCV. As you apply vacuum, the actuator should move freely, about 5cm. If it does not move or it sticks, then you probably have a failed actuator or coked-up VNT vanes.

VIDA is really useful here, you can operate the VNT directly.

[phil13]

Thanks Greg,
Hopefully I will have it Wednesday so can get looking / testing then, if that fails then I will just have to try to get to Kendal to main dealers. So if I do start it up and immediately keep revs above tickover ,it will Rev cleanly and redline and runs fine, with no smoke or roughness, would that still indicate a turbo fault?
Many thanks Phil

[gmonag]

I can't say. I'm only trying to give some direction for the diagnosis.

[phil13]

I know and your input is greatly appreciated.
Cheers Phil

[phil13]

Just a quick update, removed belly pan tonight and had a good look underneath, no signs of leaking boost , pipe work seams fine, although my set up didn't have any sealing rings/washers between the under belly pipe and the turbo flexi pipe as surgested , the flexi pipe has a yellow nitrile type liner? Just waiting for my vacuum tester to test the pipe work and actuator . When I got back in the car I scanned the faults again and had the same fault , boost pressure sensor, I cleared the fault with ignition on but engine not running, and message disappeared,but after 30 seconds it threw the fault up again without the engine running. Is this pointing to the sensor? as surely anything to do with the vacuum /boost side would need the engine running to establish a fault?
Cheers
Phil

[Clan]

Originally Posted by phil13

Just a quick update, removed belly pan tonight and had a good look underneath, no signs of leaking boost , pipe work seams fine, although my set up didn't have any sealing rings/washers between the under belly pipe and the turbo flexi pipe as surgested , the flexi pipe has a yellow nitrile type liner? Just waiting for my vacuum tester to test the pipe work and actuator . When I got back in the car I scanned the faults again and had the same fault , boost pressure sensor, I cleared the fault with ignition on but engine not running, and message disappeared,but after 30 seconds it threw the fault up again without the engine running. Is this pointing to the sensor? as surely anything to do with the vacuum /boost side would need the engine running to establish a fault?
Cheers
Phil

I did explain early on in Post#4 above how to check the atmospheric pressure reading with the engine not running .. should be around 1000 millibar depending on the weather conditions . ...

[phil13]

Sorry Clan,
I'm not sure of what or where I should be testing or what I should be testing them with? Can you elaborate please
Many thanks Phil

[Clan]

Originally Posted by phil13

Sorry Clan,
I'm not sure of what or where I should be testing or what I should be testing them with? Can you elaborate please
Many thanks Phil

In the ECM parameters there are 3 or 4 atmospheric pressure sensors
for example:

boost pressure
inlet manifold pressure
exhaust manifold pressure
atmospheric pressure

it depends on different models and years , they should all read atmospheric pressure and read very close to each other , one will probably be more out than the rest and it is always the boost pressure sensor in the intercooler pipe .

Atmospheric pressure varies around 1000 mb