Zemco CompuCruise and fuel pumps

[Tom Jennings <tomj@xxxxxxx>]

Speaking of electric pumps!

Does anyone recommend a reliable electric fuel pump with built-in  
regulator? It's a stock, carbed, 258 in a Hornet. Too many products  
are high volume/high pressure, and I want to avoid a separate  
adjustable regulator and all the hoses and adjustments. 3psi at 20  
gal/hour peak is fine.


The day before the Santa Fe trip I got the two main sensors of the  
CompuCruise installed: fuel flow sensor and driveshaft rotation  
(mph). I don't like making changes to things like fuel systems the  
day before a trip but, ...

(I've had the control/display box mounted for months, just not the  
sensors...)

I got a 100% complete, all manuals, parts, pieces, even the little  
tubes of glue, cable ties, the whole thing, for $5.00 at a surplus  
place a few years back. Missing only the top of the box. A hell of a  
find!

I'm having trouble with the fuel sensor; it works, but is erratic,  
about 5% - 10% error over a tankful. (eg. CompuCruise says I used 9.5  
gallons, but I used 10). I suspect it's the pulsing action of the  
stock diaphragm pump. I've got the sensor in the suck side, not the  
pressure side. The error is plus and minus actual; if it was  
consistently one or the other calibration would fix it.


Zemco FY-technical-I aside:

Zemco chose a really flexible and simple way to calibrate sensors.  
For example, the driveshaft sensor is a coil bracketed to run about  
1/4" from the driveshaft, and 2 or 4 magnets glued to the driveshaft;  
the fuel sensor puts out pulses with fuel flow.

Rather than "hard" calibration (eg. changing gears, etc) you  
calibrate MPH using highway milemarkers: you enter a starting  
milemarker, then miles down the road, another (CALibrate). The box  
calculates the needed correction factor. Simple!