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Author Topic: 2002 Omega 2.2 DTi Estate – Diesel Y22DTH vacuum issue  (Read 292 times)

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  • Hampton Middx
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2002 Omega 2.2 DTi Estate – Diesel Y22DTH
After an MOT back in October I began to suffer from the management light coming on, car into limp mode, and then OK(ish) above about 2000rev. I took it back to the garage; they checked, found an error code and replaced the EGR valve. Turned out the problem wasn’t fixed so they messed about a bit then told me it was then the boost gate.  Because of lockdown I couldn’t go long distances and as all the local roads are now 20MPH zones I decided to temporally live with it rather than keep replacing components.
  Having trawled through this wonderful group I’m now pretty sure it’s the dreaded leaky vacuum system issue seemingly caused by perished rubber connectors, I eventually found some spare rare & expensive rubber elbows and straights in Turkey (unfortunately before I discovered the post about using very cheap and abundant silicon tubing instead) and replaced a few obvious contenders – no real change. So I printed out the best suggestions on the forum about the issue (see below) and last week took those print-outs and spares back to the garage; again they had no luck and gave up. I suspect that back in October they pulled a few pipes apart and failed to put things back correctly, as there are no decent schematics of the system I’m not that surprised.
  I’ve read reports on here (but can’t seem find them now) that some wise guru mechanics have cured the infuriating problem for fellow members; does anyone know where I can find someone around south west London (or further afield as I can get up to 50mph on the motorway) who could help me. Obviously I expect to pay for the service.

Advice gathered from The Forum:-
“…Bottom line is that these diesel setups are simple.
A very useful diag. tool is a Gunsons Lo-Gauge, this allows you to measure the vac in the system be it pre or post actuator valve. You can also use the 'suck' method to test things by sucking on certain pipes to ensure the actuators operate.
« Reply #39 on: 15 September 2013, 14:51:57 »
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 driver’s side of the car upon starting the engine?

« Reply #40 on: 15 September 2013, 14:57:39 »
P.S. The 2 vacuum pipes that disappear into the car, one comes from the vacuum reservoir on the pollen filter housing, feeds  into the car as a vacuum feed for the air recurculator valve for the climate, and the other comes back out of the same grommet and feeds the heater bypass valve below the exhaust.
So, the vacuum system is split 3 ways. The brake servo, the climate control feed, and the engine systems feed. Hence the need for 2 reservoirs.”

Many thanks for any help


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Re: 2002 Omega 2.2 DTi Estate – Diesel Y22DTH vacuum issue
« Reply #1 on: 25 May 2021, 18:43:06 »

So if you think the turbo isn't boosting correctly, it is worth check if the vac system can hold a vac, but also that the mechanism on the turbo still works and isn't seized/stiff.

Its not clear from above what diags you have done.  Have you got the fault code(s) that are in the engine ECU, so we can start to work out what the ECU thinks is out of expected values.
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Re: 2002 Omega 2.2 DTi Estate – Diesel Y22DTH vacuum issue
« Reply #2 on: 16 June 2021, 15:17:34 »

Thanks for your reply
   Sorry my description was rather unclear, I blame Covid Brain Fog.
The turbo spins freely, the valve mechanism is a little stiff but I don't know how free it should be (it doesn’t move when I start the engine). I don't have the actual fault codes but initially the garage said it showed EGR valve issue; the valve was replaced and everything seemed fixed until I drove on the motorway at about 60 when the turbo failed to kick in and the management light came on again, this time the code showed "boost gate fail"(I had already noticed that the turbo seemed unnaturally quiet during urban use). The garage spent some time investigating the issue but when it seemed to me that they might just keep on replacing expensive units I took he car home and decided to investigate the issue on here (there’s plenty about the infuriating problem here and some expert answers that mostly point to vacuum integrity but it takes some trawling to find all that knowledge)
   I think that the emission test for the MOT was too much for the poor motor and overstressed it; I suspect that the initial main issue was vacuum leaks and possibly later on the garage mechanic may have reconnected vacuum pipes, somewhere around the injectors, incorrectly. Currently the engine runs in limp mode, with the management light on, until it gets to about 1,800 – 2,000 revs under load, when the light goes off and I get some power (I never hear the turbo) when the engine is no longer under load it goes back into limp mode -  it seems to me that all that coincides with the EGR valve cutting in and out but it’s just a guess.
   I’ve not been a home motor mechanic since you could almost reach all the engine parts standing next to it under the bonnet, I have recently replaced a few iffy rubber elbows and connectors but, because I’m old I can’t reach many of the out of the way ones and fear dropping those I can into the dark depths.
   So, the long and the short of it is – can anyone suggest a garage/mechanic, who understands this engine in this car, relatively near to me in Surrey who can either fix it or tell me the old girl is no longer viable.
Thanks for reading
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