Vince,

these folks sell some $125 pressure sensors if your
fuel(s) are compatible with Viton.  They also have a chemical
compatibility chart link in the pressure sensor area.
Current loop
(4 to 20mA) type outputs are nice for running long cables to sensors in
electrically noisy environments (spark ignition systems can be noisy
;-)  They also make it easy to diagnose broken wires or dangling
connectors.

http://www.automationdirect.com/adc/Home/Home

Craig Taylor