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Lucius Silanus · Joined: 20 Jul 2004 Posts: 24 Location: Green Bay, WI

My car started getting louder and louder, then started backfireing all in the course of a drive down the highway. I looked around and found a tube running from just beneath the oil filter coming out of the exhaust which ran under the engine, came up by the dipsitck, ran behind the engine and into the bottom of a sensor. It had sheerd right where it comes out of the exhaust.

I got the tube out, save for the part rusted onto the exhaust (not sure how to get that off just yet. . .) and held it in front of the car orientated how i got it out.

I'm not sure how to get the sensor off the tube either, it is rusted on. Got one nut free easily tho.

Any thoughts as to how to get those pieces off or a quick description of what this is for would be appreceated. Also, I'm just guessing that the piece bolted to the side of the engine just left of the throttle is a sensor:P
(oh, and if there is a way to resize pictures when posting them, that would be nice to know. . .sorry about their size)
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-lucius silanus
1978 924 owner as of june 04

Smoothie · Posted: Fri Jul 15, 2005 8:27 am Post subject:

Image resizing - http://www.924board.org/viewtopic.php?t=12941

That part you're holding is an EGR valve (exhaust gas recirculation). It's an emissions reduction device,
but also cools the combustion process and thereby lessens engine knock. The reason for the engine getting
louder is obvious, but why the backfiring?, I'm not 100% sure - maybe with that connection lost, it was
drawing in fresh air, throwing off the air:fuel mix when the EGR was opened. -That lean running plus
the lack of the combustion cooling effect probably had the engine running tooo hot, possibly resulting in
the backfires and poor running.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

numbbers · Posted: Fri Jul 15, 2005 10:18 am Post subject:

A malfunctioning EGR valve will always cause backfires. That is the primary simptom of a bad valve (stuck open). Your valve may be OK, since your broken pipe will have the same result as a valve that is stuck open.
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1980 924 Turbo

numbbers · Posted: Fri Jul 15, 2005 10:18 am Post subject:

A malfunctioning EGR valve will always cause backfires. That is the primary simptom of a bad valve (stuck open). Your valve may be OK, since your broken pipe will have the same result as a valve that is stuck open.
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1980 924 Turbo