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Made a huge mistake and it seems the engine survived without a scratch.

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I recently re-wired my SSR that controls my large external MagnaFuel pump thats triggered under RPM/MAP. I put the output into a test mode to verify the pump was still function correctly. I made the mistake of forgetting to take the output out of "test mode" so the pump never turned on when I took the car out for a drive. I also made the mistake of not enabling my Lambda and Fuel Pressure warnings (I know I know smh).

The engine went INCREDIBLY lean for a long period of time at 28psi, the only reason I noticed it was because the car felt slow. I did another short hit and noticed my Fuel correction was at full lean correction. After looking at the log my heart sank, I thought the engine was toast. I did a compression test and it was 165-170 across the board!! (still need to do a leak down test)

I think the only thing that saved the day was the E85 in the tank. Even with the engine all the way lean it never miss-fired or detonated, it just felt slow. I have now setup all the safeties so the M150 can tell me when I screw up.

Am I correct in assuming that the E85 was my savior in this situation?

Attached Files

Thanks for sharing

Some engines can survive unbelievable lean conditions as long as there's no detonation/knock involved, but good point on implementing safety features! That should be one of the reasons we use sophisticated ECUs.

Very likely - good quality exhaust valves also helps.

Either way, seems like a lucky escape.

Actually you're so far lean that the combustion temperature will start to drop. The relationship between combustion temp and lambda isn't linear. At very rich and very lean mixtures the combustion temp is lower. you tend to find the combustion temp peaks around the lambda value that provides maximum power. Being that lean would also correspond to a decent reduction in engine power (which sort of goes hand in hand with the reason the combustion temp is lower). When you start moving leaner than stoich the next problem you strike is a lean misfire as it becomes quite difficult to light off a very lean combustion charge.