Solenoid Power Valve control

V-6 Vegatex · Jul 15, 2004

After looking at the description on how to make an solenoid-operated PEVR substitute on the Before Black site, I came up with a set-up that works. I finally got a boost light pressure switch from a TR that works, and then I went to my local International Trucks parts counter. I've found they often have oddball applications not available from teh auto parts stores. I told the parts guy I wanted a solenoid operated vacuum valve that would allow vacuum to flow when the valve was not energized, but would cut off flow when it was energized. He came back with a valve for a pneumatically-powered fan that was wired to turn on when a separate thermal switch closed. It can be set up either normally-open or normally closed. The vacuum solenoid was $60.00, and although it's big, it is also bulletproof! I brought it home and mocked up the electrical circuit with some test leads, wired the boost switch in series on the hot side of the solenoid, and used a hand-pump to simulate boost to the boost light switch. Darn if it doesn't work perfect! I even hooked in a 12v lamp to verify operation and I'll keep that as a boost light in combination with a vacuum/boost gauge. I'll post pictures when I get access to a digital camera and I'll do a wiring diagram; but this is even better than the one on the website because the electrical circuit is simpler.

Later,
Dave

V-6 Vegatex · Jul 28, 2004

Pictures of Electronic PEVR

Here's the photos as promised, finally. The valve is a pneumatic solenoid from my local International truck parts house, p/n 1689785C91. The pressure switch is a Hobbs, sold by Stewart-Warner, P/N 76-575-4 (Normally open, 4 psi, adjustable down to 3.1 psi.) The valve is wired to a switched hot lead with the Hobbs switch in-line on the hot side, and grounded on the other terminal (note color of wires from the valve). I added a light to act as a boost light and tell me the circuit is working. You can use it to replace either the two port or three port PEVR, if you are replacing the two-port (like me), simply cap the vent port that comes off at a 90-degree angle to the vacuum flow (shown open in the photo). Any questions, e-mail me at; denglish@ipapilot.org

pontiacjeff · Aug 3, 2004

I see all this talk about replacing thee vacuum switch... is it due to non-o.e. installations or lack of replacement parts? Or is it b/c the electric is better? I have a two-port switch I plan to use and it seems to work like it is supposed to on the bench.

V-6 Vegatex · Aug 3, 2004

"is it due to non-o.e. installations or lack of replacement parts?"

Both of the above. I'm installing a non-O.E. turbo set-up in a Vega, but I've been trying to get a working PEVR valve for several months. None I've found work, either they operate at too high pressure or they are completely gummed up and don't work at all. If you have one that works, great; use it until it doesn't work any more. If you eventually need to replace it, you can use a three-port solenoid valve and just block the vent port if your old PEVR was originally the two port design.

Regards,
Dave

pontiacjeff · Aug 3, 2004

It the two-port. I assume one port goes to the carb, but where does the other go? and which is which??? Thanks.

V-6 Vegatex · Aug 3, 2004

Both go to the carb. One goes to the power valve port, which is the small port in the middle of the carb base plate. The other goes to a vacuum port on the carb. Mine is on the upper left when looking at the front of the carb. This is a 1980 diagram; see if it helps:

Solenoid Power Valve control

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