91 egr

fishonanon · #1 03-12-2008, 02:05 AM

I just bought a 1991 geo metro this weekend and have pulled the head and having it redone. I read that the EGR valve do to being bad or pluged can cause the #2 cyl valves to burn . It just so happens that the exhaust valve on the # 1 was visably bad but will find out soon what else was bad. I dont know what the EGR valve looks like or where it is. It would be great if someone had a diagram or photo of it. I was also told that the exhaust system can cause the valves to burn up on these motors also. Is that also true? Also are there any online manuals for Geo Metro's

RossT · #2 03-12-2008, 03:10 AM

If your 91 has an automatic transmission there is a good chance that it does NOT have and egr. Back then not all came withe the egr. My 91 automatic did not have and egr, and it had a vacuum advance on the distrib. Those that have the egr, the advance is controlled by the computer.

Follow this link, you will see what the egr looks like:
http://www.teamswift.net/viewtopic.php?t=25919

Also look at the big white sticker uner your hood. It has an emisions diagram. If you have the egr, it will be listed there.

Rooy · #3 03-13-2008, 02:27 PM

My 91 with a manual trans also did not come equipped with an EGR system.

And it also has the distributor with vac advance.

fishonanon · #4 03-13-2008, 11:03 PM

Rody and Ross T,

I really appreciate your responce. Thank you for writing.

Doug

91Caprice9c1 · #5 03-14-2008, 02:35 AM

In response to your question: "I was also told that the exhaust system can cause the valves to burn up on these motors also. Is that also true?"

If you're thinking in terms of an exhaust leak, that can cause burnt valves on any motor provided the leak is close enough to the exhaust port. Which means if you've got an exhaust leak at the manifold, fix it.

This happens because a low pressure region (vacuum) is formed behind the mass of escaping exhaust gasses. Relatively cold atmospheric air is then sucked into the exhaust port and surrounds the valve. The rapid heat cycling fatigues the valve head, and the high temperature of the valve leaves it susceptible to oxidation.

-MechanicMatt

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