Diesel John,

Looking at yr pictures it seems that all is already done on diesel fuel flow measure or carburated engine measuring. Are these old fuel mileage computers still available on the market? Are they expensive, accurate? Tks for sharing.

if you search Zemco patents it was done in the 70's but forgot during cheap gas of the 80's until OBDII was forced in the 90's. The light source burned out didn't use LED's. The recirculating ball melted from heat and the fuel additives. But they are still around, saw one on ebay for $25 last year.