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[JamesV6CDX]

For the record I’m not suggesting head gasket failure is the cause. A methodical diagnosis is obviously needed

I was just saying that it did happen to my 2.2

[terry paget]

Thanks James, I was puzzled by the sudden misfire at low revs, which seemed inconsistent with oil on coil pack.
Resigned as I was to swapping the cat section yet again, I have removed the coil pack and the the cam cover unit first. It occurred to me I might manage to siphon the oil out of cylinders 3 & 4 via the plug holes to avoid burning it off with engine running or risk poisoning my young catalyst.

Imagine my surprise; I turned engine to raise 3 & 4 to the top, expecting to see a sea of oil in pots 3 & 4 - not the case! They are as dry as 1 & 2! The oil must have drained past the rings into the sump.

So, no need to swap cat sections for the initial burn after changing cam Cover gaskets, then swap them back again. All I need do is fit new cam cover gaskets, clear the breathers, fit new plugs, and fire up, praying that it idles sweetly.

[Doctor Gollum]

Not fixing the manifold is a mistake...

As is assuming that the oil gets past the plugs... Oil in the plug wells degrades the insulation properties of the coil pack rubbers to the point of affecting spark voltages... Hence the misfire.

[terry paget]

Not fixing the manifold is a mistake...

As is assuming that the oil gets past the plugs... Oil in the plug wells degrades the insulation properties of the coil pack rubbers to the point of affecting spark voltages... Hence the misfire.

Thanks for the advice Doc. In my defence the manifold was cracked last year and passed MOT. In fact every 4 cylinder petrol Omega I have ever owned has sported a cracked exhaust manifold. I had one welded up, but it cracked again within the year. As commented earlier, the manifold retaining studs into the head are prone to breaking off in the head.
I shall examine the insulators for cracks before reassembly.  Other members have commented that oil is not a bad insulator!
I appreciate getting this car through its MOT will be a struggle. It only cost me £190 2 years ago.

[terry paget]

You think...

Still, at least you now know why it's misfiring...

Sort the camcover, change the plugs, check the coil pack and report back

Camcover sorted, plugs changed for new, coil pack cleaned up and all reinstalled. Engine ran, but misfired at idle and low revs. Diagnostic said misfire cylinders 1 & 3. Am investigating.

[Doctor Gollum]

You think...

Still, at least you now know why it's misfiring...

Sort the camcover, change the plugs, check the coil pack and report back

Camcover sorted, plugs changed for new, coil pack cleaned up and all reinstalled. Engine ran, but misfired at idle and low revs. Diagnostic said misfire cylinders 1 & 3. Am investigating.

Given that the fault has moved cylinders, I would suggest the coil pack is past its best...

[mandula]

Or still that exhaust manifold crack messing up idle and low revs?

[terry paget]

You think...

Still, at least you now know why it's misfiring...

Sort the camcover, change the plugs, check the coil pack and report back

Camcover sorted, plugs changed for new, coil pack cleaned up and all reinstalled. Engine ran, but misfired at idle and low revs. Diagnostic said misfire cylinders 1 & 3. Am investigating.

Given that the fault has moved cylinders, I would suggest the coil pack is past its best...

Thanks Doc, good advice. Have I a spare coil pack, I wonder? I rummage. To my surprise I find a coil pack marked '2.2'. With it I find a complete induction tract marked '2.2'. I decide to fit the induction tract first.
Fault disappears! Engine starts, idles, pulls normally.

[shyboy]

Well done, Terry.
What's an induction tract?

[Nick W]

Well done, Terry.
What's an induction tract?

it's the hollow bit of the inlet manifold

[terry paget]

Well done, Terry.
What's an induction tract?

The assembly of hoses and mass air flow meter that connects the air cleaner to the throttle box. Fitting involves 2 hose clips and one electrical connector.

[Andy A]

Well done, Terry.
What's an induction tract?

The assembly of hoses and mass air flow meter that connects the air cleaner to the throttle box. Fitting involves 2 hose clips and one electrical connector.

Terry do you have the part number or size of the two hose clamps that connect the air flow meter?

Mine are knackered.

Glad you got it all sorted.

Thanks

Andy

[terry paget]

Well done, Terry.
What's an induction tract?

The assembly of hoses and mass air flow meter that connects the air cleaner to the throttle box. Fitting involves 2 hose clips and one electrical connector.

Terry do you have the part number or size of the two hose clamps that connect the air flow meter?

Mine are knackered.

Glad you got it all sorted.

Thanks

Andy

S3 size 40
29-76 USA
one is labelled,
the other says NORMA 72-80
make of that what you will
The diameter of the clamp point seems to about 76mm

[terry paget]

Well done, Terry.
What's an induction tract?

The assembly of hoses and mass air flow meter that connects the air cleaner to the throttle box. Fitting involves 2 hose clips and one electrical connector.

Terry do you have the part number or size of the two hose clamps that connect the air flow meter?

Mine are knackered.

Glad you got it all sorted.

Thanks

Andy

S3 size 40
29-76 USA
one is labelled,
the other says NORMA 72-80
make of that what you will
The diameter of the clamp point seems to about 76mm

Correction: those are the hose clips either side of the air flow meter, not the ones I touched. The air cleaner end clip is labelled 82-92 NORMA, the throttle body end clip is labelled Norma 66-75.

[TheBoy]

So, was it a split in the old inlet?