A neighbor who runs a shade tree tractor shop called me one day to see if I could help him get an engine started after an in-the-frame overhaul. He had installed piston rings and rod bearings, had the cylinder head reworked by a machine shop, etc., on a Dodge Ram 50 (Mitsubishi) 4 cylinder overhead cam engine. It would run for about 5 seconds, backfire, and refuse to even hit again on subsequent attempts at starting it. After 5 minutes or so, it would do the same thing- - -run a few seconds and quit- - - -repeatedly!
I checked ignition timing, compression, even cam timing- - - -all good and right on specification. After about 5 or 6 timing checks, I cranked the engine and it ran- - - -and kept running- - - -but it made some nasty noises because I had left the #1 spark plug out after checking for compression one more time! Put the plug in- - -crank the engine- - -run 5 seconds and quit! I could remove any spark plug, 1,2,3,or 4- - -and it would run! It WOULD NOT keep running with all the plugs installed!
Got any guesses now?
Jerry