Omega 2.5 V6 Problem

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Thu 19 Feb 2004 18:29
Omega 2.5 V6 Problem - Taters
I have an 1994 Omega 2.5 V6 which has the following problem.

The engine is down on power, there are no fault codes from computer, there is a small rubber pipe that keeps melting/exploding. This pipe is part of the secondary air injection system. The pipe connects the nearside bank of cyclinders to the centre pipe.

Any ideas?
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Thu 19 Feb 2004 19:41
Omega 2.5 V6 Problem - geoff C
The non return valve may be stuck open, allowing hot exhaust gases to enter this pipe. This might then have caused a problem with the control valve, especially if it has been subjected to hot exhaust. The non-return valve is screwed into the metal centre pipe and is joined by a rubber hose to the control valve, which is vacuum operated. The air pump is under the wheel-arch, in front of the arch liner.

Normally the air injection pump runs for a minute or two after a cold start. When the pump stops the control valve also closes. The non-return valve is spring loaded to the closed position and should prevent any back-flow of exhaust. I'm not sure why the control valve is needed.

Remove the rubber pipe from between the control valve and the non return valve and start the engine. If exhaust gases emerge from the non return valve then it is not closed. (Note it is normal for there to be quite a loud roar from this with the pipe off, even when the valve is closing properly. On my car the pipe between the control valve to the non-return valve was faulty and split, causing this noise, but no flow of exhaust gas.
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Thu 19 Feb 2004 19:49
Omega 2.5 V6 Problem - Taters
Thanks for the info.

The pipe in question is the manifold side of the non return valve it connects two copper pipes, but I will check it just in case.

It seems like too much exhaust gas or pressure is going along it.It's fine on tick over but when I take it out for a test drive if the engine gets any where near top revs it blows!

Strange
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