Over a year ago I had my RX-8 engine quit while on a short flight. (I fly 13 miles to Georgetown (40XS - GTU) 3 to 5 times a week to play tennis). When the engine quit I was at 700 feet above the ground and 6 miles from home. I quickly checked the EM-2 and saw the oxygen sensor was off the scale. I turned the mixture full rich and the engine started producing some power. It was enough to make it home. I tried the B controller and the power decreased slightly so I went back to the A controller. By that time I was close to entering the landing pattern at a low altitude so I did not try anything else.
I make it home and landed OK. On the ground the engine idled great with the mixture set at 12 o'clock so I went to cruise power several times and it went lean and tried to quit until I made it full rich. I shut it off and than restarted it. This time it ran perfect!! I tried it many times but it did not act up again..
I talked with Steve Bose, Bobby Hughes and Mark Steitle about the problem and after much head scratching and tests we decided the only logical conclusion was that one of the injector circuits must have gone open circuit. This would reduce the fuel flow by half but because the injector switch was not turned to the off position, the computer did not double the fuel to the other working injectors.
I ran tests where I disconnected one set of injectors and duplicated the problem exactly. I than checked all the wiring but found no problems. The rocker switches I was using to control the injectors were the next suspect so I removed them and cut open the switches to inspect the contacts. The contacts looked fair but it was found that in the closed position - very little pressure held the contacts closed. After 6 years of use it appears that the contacts in the leading or trailing injector circuit did not stay closed completely on this flight. The flight was quite bumpy with gusty winds from the south at 25 to 35 mph.
I replaced the rocker switches with very firm snapping toggle switches (I assume this means high contact pressure). I have not had any more problems. The rocker switches were purchased from Digi-Key – # SW323-ND is one example. I liked the looks of the rocker switches on the instrument panel at first but now toggle switches look great!
I highly recommend you only use high quality and/or Mil Spec. toggle switches for all the engine related electronics. Bobby Hughes has always advised this! You may find cheaper toggle switches are OK for non critical applications such as lights.
Dennis Haverlah
RV-7A ~ 600 hrs. flight time on 4 Port RX-8 Renesis