Hello All,
I bought an '89 740 GL for my daughter, and was experiementing with the EGR vacuum controller valve yesterday (with a vacuum tester). The upper port on the controller valve (white hose - intake manifold to controller valve) will hold vacuum; the lower port (yellow hose from controller valve to EGR valve) will not hold a vacuum. This was tested directly at the controller valve nipples. It seems the lower chamber vents to the atmosphere (or leaks.) Shouldn't the lower chamber also be able to hold a vacuum? Haven't tried checking to see if the valve clicks when the engine is running - was more concerned about how the valve operates. Anyone ever take one of these controller valves apart?

http://brickboard.com/RWD/index.htm?id=1032842
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Andy in St. Paul. '89 244 160K mi, '91 745 209K, '91 745 213K

Really appreciate the heads-up - it is difficult to find solid information on the EGR system. Thanks again.

EGR in an '89 740? I'm not an expert by any means, but being an '89 740 GL, it came with an 8-valve, non-turbo B230F engine with either LH 2.4 or possibly Rex-Regina engine management. I see that you are in Maryland, so I will presume this car was made for the North American market. With the possible exception of a car originally sold in California, or an engine swap from a 940, I'm surprised to hear "EGR".

But check this out in the 700/900 FAQ anyway:

http://brickboard.com/FAQ/700-900/EngineSensors.htm#EGRValve
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Andy in St. Paul. '89 244 160K mi, '91 745 209K, '91 745 213K

Apparently the car is a California model; don't know how many 740's Volvo sold in California in '89, but this one ended up in the D.C. area. If I had done my homework (better) prior to buying the car and known it was California-spec., I would have passed it up.

I'm sure a lot of them were sold in California every year. If not, it wouldn't have been worth it to Volvo to make a special version for that market.

I do recall from previous ECU discussions that for LH 2.4 (you have that right?)the EGR and non-EGR ECUs are compatible (at least in one direction or the other). That makes me wonder if you could eliminate the EGR setup without too much trouble except for maybe an ECU replacement.

Maybe Art Benstein would know, but I suggest you search the archives on EGR and ECU, especially on the 240 board. I haven't heard of anyone eliminating EGR, but there might be a lot of clues out there if you are willing to wade through a lot of posts.
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Andy in St. Paul. '89 244 160K mi, '91 745 209K, '91 745 213K