Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[P6UL K]

The only thing to go wrong with the vacuum reservoir on the pollen filter box is the two rubber elbows on the top perishing...

I've inspected both these and they seem ok, but I might renew just for peace of mind

[P6UL K]

Is the management light on, if not does it flash on when you start up?

Nope all seems fine on that front, all the idiot lights come on and go off fine... No EML at all :-/

[P6UL K]

Best way to test the vacuum system is with a vacuum gauge. It should read at least 25 inches. Flick / wobble all the rubber connectors. Any drop in the vacuum reading when you disturb a rubber connector means its split or perished. The U shaped vacuum bridge at the back of the head in particular suffers from the heat and perishes or collapses, which is critical because it supplies everything other than the brake servo and causes all sorts of nasties.

The turbo is a variable geometry unit, so it doesn't need a wastegate. The device the vacuum pipe feeds is to adjust the vanes. With vacuum applied the vanes are fully extended, This is the normal operating condition at idle. When the boost sensor towards the back of the inlet manifold senses the boost approaching 2 bar, the vacuum is cut off, the vanes retract and boost is controlled.

Also, in the event of the ECU (or EDC) picking up a critical malfunction, limp mode is activated, one feature of this is that the boost solenoid is deactivated, the turbo actuator gets no vacuum so boost is inhibited.

Are you getting vacuum to the turbo actuator at idle? You should see the actuator pull towards the drivers side of the car upon starting the engine?

Dragged SWHMBO round with me this morning just to start the car while I watch the actuator and it does move completely in like you said it should... Took it out for a quick drive but still no boost - very strange!

[P6UL K]

Out if my box of bits supplied by someone on here who I can't recall is...



Any hints on where these go?

I've just changed the boost sensor and its still the same, not going to bother with the vac pump - although I've not measured the vacuum strength it seems to be working ok.

Which just leaves that other part? Any idea what it does and where it goes?

[andymp]

When you start the car, and the actuator pulls inwards, rev the engine quite heavily. You should see the actuator swing towards the passenger side of the car to control the boost as it reaches 2 bar, and the hose from the intercooler to the inlet manifold "blow up" under boost pressure, and the actuator should pull in again upon return to tickover.

Any loud hissing noises and black smoke from the exhaust indicate a leak of boost pressure, from a burst hose or damaged intercooler?

The actuator pulled in and no increase in boost with engine revs, would suggest a defective turbo, stuck vanes maybe? With the engine switched off, take the hose off the silver end, look inside and see if you can spin the spool, and that it doesn't have excessive movement up and down?

[andymp]

The vacuum feeling OK isn't enough... It should be measured with a gauge and have at least 20 inches.
The two most indispensable tools for the miggy 2.2 dti :-

• A handheld vacuum pump / gauge
• "O P Com", and a OBD-II extension lead with a right angle male connector to make driving whilst "O P Com" is connected possible...

[P6UL K]

When you start the car, and the actuator pulls inwards, rev the engine quite heavily. You should see the actuator swing towards the passenger side of the car to control the boost as it reaches 2 bar, and the hose from the intercooler to the inlet manifold "blow up" under boost pressure, and the actuator should pull in again upon return to tickover.

Any loud hissing noises and black smoke from the exhaust indicate a leak of boost pressure, from a burst hose or damaged intercooler?

The actuator pulled in and no increase in boost with engine revs, would suggest a defective turbo, stuck vanes maybe? With the engine switched off, take the hose off the silver end, look inside and see if you can spin the spool, and that it doesn't have excessive movement up and down?

Hi Andy,

Upon starting the car the actuator does as you say it should, pulling across to the drivers side but under hard revving it doesn't seem to move at all - although the boost pipe onto the inlet definitely swells quite a bit.  I had the N/S boost pipe off to see if it was split but its also seems ok, i did consider maybe the intercooler has collapsed or there is something blocking it?

Funny you mentioning a defective turbo as its actually a brand new unit from Essex Turbos, not sure when it was renewed as i dont have any paperwork for it but James/Twiglet told me about it but the car has sat on and off since Aug 2011... I have fully serviced the car.... New oil, filters etc to cover that base - I'm really stumped tbh!

[P6UL K]

The vacuum feeling OK isn't enough... It should be measured with a gauge and have at least 20 inches.
The two most indispensable tools for the miggy 2.2 dti :-

• A handheld vacuum pump / gauge
• "O P Com", and a OBD-II extension lead with a right angle male connector to make driving whilst "O P Com" is connected possible...

A mechanic friend is coming over tonight with his vacuum measuing tool, so i'll let you know on that one chap

[andymp]

The actuator should react to boost pressure readings from the sensor in the inlet manifold, that you've changed. If the hoses are blowing up, it is boosting, but if the actuator doesn't limit it, that says the turbo isn't giving enough pressure, or its escaping somewhere?

[P6UL K]

Am i right in saying that you wouldn't get normal boost running like you would if the car was under load? 

I'll check the other boost pipes later but there isn't the normal 'boost leaking' noise that you get like I've experienced on previous turbocharged petrol cars.

Its a bit cheeky, but could i call you later this evening when i'm back at the car with my mate?  Prob be around 8pm-ish.

Perhaps its not a vacuum issue after all, still a frustrating one tho!!

[P6UL K]

Right mechanic friend has been and gone and he is as frustrated as i am now! 

We swapped the AFM over, unplugged this and checked all number of things, really strange now that all the vacuum issues are done and this is still happening.

He has said that its almost like the car has gone into limp mode but there is no lights on the dash, so tomorrow he's going to plug in his Code Scanner and take the car for a drive to get some live readings as to what maybe up with the car - May have logged some fault codes.

I'll report back in due course.

[05omegav6]

No lights suggests that the bulb(s) are missing/dead. No telling what had been fiddled with before Twiglet bought it either

[P6UL K]

I did suspect that but as it was a funeral car I dismissed it

[05omegav6]

When I get a mo ishall rummage for the oruginal query

[05omegav6]

When I get a mo ishall rummage for the oruginal query

http://www.omegaowners.com/forum/index.php?topic=102831.msg1286717#msg1286717

The trouble with it was present long before Twiglet bought it... had been suggested that someone had been meddling when they went to view the car