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Old 03-16-2020, 09:13 AM   #15 (permalink)
racprops
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Join Date: Oct 2009
Location: Phoenix AZ
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I have one of each of the two first gauges, and like them. The Turbo gauge seems to have More features....

I also have a couple MPGunios, mainly because I had planed on doing things with the injectors, even one plan that might bypass the injectors so along with the above scan gauges I have a two of the very old Zemco automotive computer...sadly the great models I own are so rare I could not find any of them, not on ebay not in a wide search...just this older model: https://www.ebay.com/itm/Vintage-NOS...-/273868141978

Here is a picture of the great head unit in my 93 Chevy van. https://www.facebook.com/photo.php?f...type=3&theater

These work off its own VSS sending system by mounting a set of magnets to the drive shaft close to the transmission, and mounting a small coil close to them, running wires to your dash. this gives miles driven, MPH and is used to compute the MPG with a fuel flow sensor that is mounted in line from the fuel pump and the carburetor. This flow sensor tells the computer how much fuel that flows to the carburetor. With these two sensor these computers could tell you your MPG, MPH, range, as in miles to out of gas. And a few other read outs. There was a calibration needed, so for the first trips you needed to make adjustments to refine its readings.

I ran one in my 1974 Chevy van. It worked very well. During the gas shortage of the 70s having a read out to out of gas on road trips was a great help.

A few things I need to point out: These were low pressure systems, 5 PSI, I do not know how well the fuel sensor will work with 30 to 90 PSI systems.

Another problem with OBDI FI systems had fuel return systems, fuel fed to the fuel rail that was not used was bypassed and fed back to the gas tank. The fuel sensor cannot tell how much fuel was used by the engine. Even my 74 Van has a fuel return system but it was at the engine driven fuel pump so from this fuel pump was one fuel line to the carburetor so the sensor could read only the fuel fed to the carb.

I was trying to rig a aftermarket Fuel Pressure regulator that had a external fuel return that would allow the system to then feed the fuel rail as a direct line from this external fuel pressure regulator allowing the fuel flow to read the fuel fed to the fuel rail.

I did get this system rigged on my 93 Chevy van bypassing the TBI injector pressure regulator built into the TBI injector system, but ran into some kind of problem and ended up removing the system. The van runs at 10 to 20 PSI fuel pressure. It had no leaks at that pressure, I cannot say how it will handle higher PSI of other systems.

I also heard that the gas flow sensor did not have a great life, and can wear out, so was looking into better fuel flow sensors to handle higher fuel pressure system. I did not find one then.

Rich
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