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Folks, I have a fresh 370 build that has about 15mins of run time, mostly all idling in the garage with 3500 being the highest RPMs it has seen. Car has not been driven yet.
Engine was idling nicely when it suddenly stumbled and died. Fired it back up and ran like it was only firing on a couple cylinders then started to clatter lightly. Sound seemed to be coming from the bottom/rear of the engine. Pulled the plugs and all 8 were sooty or wet. So, with all 8 cylinders misfiring and a noise from the rear of the engine, I assumed crank sensor/reluctor. Engine is out and gone through and I feel confident the rotating assembly is good. I am chasing other things to determine source of the noise. Crank reluctor feels solid and fixed but would like to verify its alignment.
These pics are with #1 at TDC on the compression stroke and I am hoping someone could tell if the reluctor is properly aligned relative to the sensor. The project build is in the Conversion / Hybrids forum and a little more detail on the issue can be seen HERE.
^ This 100%. A loose ground could have easily backed out especially under the heavy vibration while running. Since the plugs were wet it sounds like you've got fuel (and we'll assume compression) so my guess is the plugs aren't firing. Your coils are grounded via the grounds that bolt to the cylinder head, so if it's lose or making intermittent contact the motor won't fire.
When I pulled the engine, the grounds to both heads were secure and I have the ECU grounds running directly to the battery. When the engine was running, the Terminator X was showing normal oil and fuel pressure, 14.4V and for those familiar with the LED indicator lights, 1, 2, 3, 4 were green and 6 & 7 were off, all what you would expect if everything was normal. 6 is for Crank and 7 is for Cam and the lights are off "When above Crank To Run RPM and ECU is properly Syncd".
Since the engine was running and all the plugs basically look the same, wet, I would say yes.
Had a brain fart today but haven't had a chance to check it out yet. While this was going on with my head spinning and trying not to run the engine for any extended period of time, the one gauge setting I cannot recall looking at was MAP. What if the MAP sensor failed and was sending 5V to the signal wire? Even though the engine was just idling, the ECU would revert (I think) to using the fuel table cells for 900RPMs and 29psi boost. The fuel value at idle is 5.1 lb/hr but at 900rpms/29psi it is 102! That could explain why the engine suddenly died and at 500rpms/29psi, it is 68 lb/hr. Trying to see if my buddy will let me plug in my MAP sensor in his harness and see what it reads with KO/EO.
Can't blame him if he doesn't want to risk. Any thoughts on how I can bench test a MAP sensor with 5V since I'm pretty sure they cant handle 12V? No need for vacuum or pressure as I just want to see the voltage on the signal at atmo.
"Engine was idling nicely when it suddenly stumbled and died."
Did this happen as it was warmed enough to go closed loop?
Make a log, key on, engine off, then crank it.
Look at the log.
Can you capture any streaming OBD2 parameter ID log files? My Tech2 clone device captures perhaps a hundred engine parameters and I have saved logs from a perfectly running engine to compare with whatever your engine might be producing for these same values.
If you're going to troubleshoot a Holley EFI running problem then the first step is to get a data log. It doesn't have diagnostic codes like OEM systems, so your eyes on the data log is the replacement for that.
Also make sure your coil packs are wired properly and functioning.
Help Diagnosing All Cylinders Misfiring 
