In rethinking the notion of replacing the stock vacuum pump with an electric one, I now think it may be possible....not easy, but possible. As has been well documented, the problem is the VCV for the automatic transmission. It continuously bleeds vacuum to maintain a vacuum signal approximately equal to what a gasoline engine would generate for a comparable throttle position.

It might be possible to create that vacuum signal without a constant bleed.

I would envision such a system being comprised of a microcontroller, a vacuum sensor, a throttle position sensor (TPS), and two pneumatic solenoids - one for bleed and one for vacuum. The TPS would produce a voltage that could be read by the microcontroller that corresponds to the throttle position. That voltage would then be converted to a vacuum level which would be adjusted by activating a vacuum solenoid to increase vacuum or the bleed valve to decrease vacuum. And if there is no change in throttle position there is no bleed. In fact, the only time vacuum from the electric pump would be consumed is when there is a decreasing throttle position (vacuum is increased).

The fact that this could theoretically be done does not mean it should be done. It's a lot of work and a lot of new points of failure. Cost however would insignificant - an Arduino microcontroller is a couple bucks, a MAP sensor is a buck or two and a switchover valve is likewise a couple bucks.

Of course one could use a very small dedicated vacuum pump for the transmission and turn on the pump when vacuum is needed and use a switchover valve to bleed.

Just a crazy idea...

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

In the 1970s and 1980s a lot of smaller diesel trucks used belt-driven, bolt-on-chassis vacuum pumps to add brake boost. I have not looked for one but thought if I ever put a brake booster on a car earlier than a W115 I might use that. Has anyone looked?

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Strelnik
Invest in America: Buy a Congressman!

1950 170SD
1951 Citroen 11BN
1953 Citroen 11BNF limo
1953 220a project
1959 180D
1960 190D
1960 Borgward Isabella TS 2dr
1983 240D daily driver
1983 380SL
1990 350SDL daily driver alt
3 x Citroen DS21M, down from 5
3 x Citroen 2CV, down from 6

There is a thread where one of our Members insalled one.

However, in there are lots of more current GM, Ford and Doge pickup trucks that use belt driving Vacuum Pumps. Just do a search on eBay.

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84 300D, 82 Volvo 244Gl Diesel

The Cummins 4B series engines of the '80's used a belt driven vacuum pump.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now