Major misfire on idle, 2.2 petrol manual

[Doctor Gollum]

Being a 2.2 does not stop it being an Omega... 

All the petrol Omegas share most of the same issues. The only significant differences are that the four cylinder cars don't suffer particularly with water collecting in the plug wells from the scuttle and the V6 cam sensor failure does not upset the auto box and crankshaft sensor failure does not prevent the four cylinder from starting...

Coolant leaks are almost always hbv or radiator, oil leaks are always breather related (top end) or sump gasket/crank seals (bottom end), handling issues are always highlighted by failed front wishbone vertical bushes... etc, etc

Head gasket is a red herring in this case... Were it a V6, it wouldn't even be mentioned, even though the 3.0 is at least as prone to it.

Clean the breathers, sort the camcover leak and service it, just like you would any V6 Omega and report back.

[terry paget]

I changed the cat section 9 days ago. Easy job removing the old aftermarket one, but much trickier installing the much heavier Vx system. I would not have done the job had the engine been stalling at idle. When son Jonny brought the car home for MOT preparation it was running and idling perfectly. It was starting, running and idling fine nine days ago. The stalling and bad idling began late last week. I changed MAF sensor and front lambda sensor, hoping that would cure it - no luck. Something serious has gone wrong in the last five days

[dave the builder]

aside from the missfire / fouled plugs etc.....which needs sorting
worth checking that you have not disturbed a tight seal on the zorst manifold to head (while working on the cat)
a blowing zorst manifold gasket will also suck un-metered air via the egr port

[terry paget]

aside from the missfire / fouled plugs etc.....which needs sorting
worth checking that you have not disturbed a tight seal on the zorst manifold to head (while working on the cat)
a blowing zorst manifold gasket will also suck un-metered air via the egr port

What's the zorst manifold?  My Haynes index ends at X.

[TheBoy]

aside from the missfire / fouled plugs etc.....which needs sorting
worth checking that you have not disturbed a tight seal on the zorst manifold to head (while working on the cat)
a blowing zorst manifold gasket will also suck un-metered air via the egr port

What's the zorst manifold?  My Haynes index ends at X.

Slang for Exhaust.

[terry paget]

Thank you. I don't think I mentioned it, but there is quite a crack in the exhaust manifold, which apart from making a noise, will allow entry of air, thus inbalancing the exhaust mixture. All bad news. I have seen this before in 4 cylinder Omegas, one more reason always to buy V6s.

[dave the builder]

 explains your lean condition 
same 2.2 engine in some .....
vauxhall & Opel Astra G; Astra H; Signum;  Vectra B; Vectra C; Zafira (A); Zafira B
careful you don't order the 2.2 diesel manifold if buying off the net or traveling to collect
assuming the manifold is the same for front and rear wheel drive 

[Doctor Gollum]

Info wrong...

Not the same engine in later, ie 2005 on Vauxhalls... That is a very different chain driven beast...

[dave the builder]

Info wrong...

Not the same engine in later, ie 2005 on Vauxhalls... That is a very different chain driven beast...

I stand corrected 

i'm going to get bits off a 2.2 2002 facelift  sport tomorrow, i could inquire about the cost   ?

[terry paget]

Being a 2.2 does not stop it being an Omega... 

All the petrol Omegas share most of the same issues. The only significant differences are that the four cylinder cars don't suffer particularly with water collecting in the plug wells from the scuttle and the V6 cam sensor failure does not upset the auto box and crankshaft sensor failure does not prevent the four cylinder from starting...

Coolant leaks are almost always hbv or radiator, oil leaks are always breather related (top end) or sump gasket/crank seals (bottom end), handling issues are always highlighted by failed front wishbone vertical bushes... etc, etc

Head gasket is a red herring in this case... Were it a V6, it wouldn't even be mentioned, even though the 3.0 is at least as prone to it.

Clean the breathers, sort the camcover leak and service it, just like you would any V6 Omega and report back.

Thanks for your wisdom, Doc. This car has made a fool of me. Son returned it running well, 3 weeks ago. I plugged in my diagmoser, and was surprised to discover that the post cat mixture did not vary lean-rich at idle, unlike my other 2.2, which did. I replaced the MAF sensor and 1st cat with new, and tried again. No change in mixture control, but now the car would not idle. I found oil in plug wells 3 & 4, plug pack not dry and happy. 
Clearly more work to be done. Will report back.                                                                                                                                                                                                                                                                                                                                                                                  jk enoui

[TheBoy]

A lesson to correct diagnose before randomly changing parts, TP .  Get to understand and love your diags machine

[Doctor Gollum]

In light of the manifold crack... Best add it to the list

Cheap and cheerful...

https://www.ebay.co.uk/itm/EXHAUST-MANIFOLD-OPEL-VAUXHALL-OMEGA-B-2-0-VECTRA-B-1-8-2-0-/371141255032

Hopefully someone can confirm that it will fit

[terry paget]

In light of the manifold crack... Best add it to the list

Cheap and cheerful...

https://www.ebay.co.uk/itm/EXHAUST-MANIFOLD-OPEL-VAUXHALL-OMEGA-B-2-0-VECTRA-B-1-8-2-0-/371141255032

Hopefully someone can confirm that it will fit

2.2 does not have secondary air injection as far as I know. I have found in the past that the exhaust gasket studs in the head are inclined to breaking off. On Ben's 2.2 the 2 front studs are missing - amazingly the gasket is not blowing at that point.

[dave the builder]

If you can get to the snapped studs and drill them out ,they are pretty soft
(using good quality sharp/new drill bits)
i started with a center punch, 1.5mm , 3mm, 5mm
(depth stop marking with tape on the bits,you don't want to go too deep)
then if you have an easy out extractor set?
the stud nuts are brass/copper and soft(sacrificial in comparison to the stud),
often swapped for steel nuts ,which get over torqued and snap studs
when fitting an exhaust manifold , treat it like you would a cylinder head
evenly tighten gradually by hand, (no air tools ,impact drivers)

i've seen studs screwed into the head past the fat section of the stud (splitting the head)

[mandula]

In light of the manifold crack... Best add it to the list

Cheap and cheerful...

https://www.ebay.co.uk/itm/EXHAUST-MANIFOLD-OPEL-VAUXHALL-OMEGA-B-2-0-VECTRA-B-1-8-2-0-/371141255032

Hopefully someone can confirm that it will fit

2.2 does not have secondary air injection as far as I know. I have found in the past that the exhaust gasket studs in the head are inclined to breaking off. On Ben's 2.2 the 2 front studs are missing - amazingly the gasket is not blowing at that point.

Here's what I got few years ago: https://www.vauxhall-car-parts.co.uk/acatalog/VAUXHALL_EXHAUST_MANIFOLD_-_24420438.html