1990 Escort GT - Hard to Find Part, BVT for EGR

I'm looking for what is called a "backpressure variable transducer" (BVT for short), the analog equivalent to the DPFE sensor. The BVT is
black, round and has two diaphragms inside, with three port fittings coming out. The E port goes to the exhaust header, the B port goes to the EGR air tube, and the C port tweaks the EGR vacuum signal based on the backpressure differential between the exhaust and EGR air tube.
What happens is after so many miles the exhaust gasses wear out the rubber diaphragms inside. I popped the covers off and confirmed this. So rather than try to rig the diaphragms somehow with RTV I thought I'd try looking for a good one somewhere. A junked car would likely yield the same results if I could even find a donor vehicle.
An old parts list might help, but haven't found any yet. Anybody old pros around familiar with fixing or replacing these?. I called a dealership and their parts diagram didn't list the OE number anymore because it was obsolete, I was told.
Thanks, sleepdog
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snipped-for-privacy@optonline.net wrote:

did you check the aftermarket parts stores? RTV does sound like a good idea though....
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They only have an electronic equivalent from a similar vintage. No way I'm wiring an electonically controlled EGR and BVT into this car's processor. Not that I could...
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Could you use a rubber and canvas type cloth, like the patches made for waders? I don't know how much heat is generated to that spot, but you might be able to find something like that to use that would be flexible and stand up to the heat.
SC Tom
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SC Tom wrote:

That's a tuffy.... That cloth may hold up. Not much heat gets to the diaphragms UNTIL one gets a pinhole leak. Then you get exhaust gas flowing through. DPFEs have the same problem. IIRC, the Engine Control system on those GTs was a Mazda(?) design. It was an Escort GT only system for Ford. It also used a Vane Air Flow meter where you would expect to find the MAF. That valve may cross to another car maker. Again, I'm thinking Mazda.
Have you looked for an Escort related discussion forum? There's lots of mfgr\model specific discussion forums on the web. They are a great help with oddball problems like this. Some Escort GT fan may just have a good one laying around. I have an 84 Lincoln Mark VII and www.lincolnsonline.com has been a great help to me for finding Mark VII specific parts. Try this one: http://www.feoa.net
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