86customanche Posted February 19, 2021 Share Posted February 19, 2021 Here’s another thread on starting issues.... ’92 4.0 4wd last week it ran ok for a short drive. The next day it started and ran for about a minute, then quit. It was very rough, like a misfire or missing a cylinder. now it cranks strongly but doesn’t start, doesn’t even sound like it wants to start. I depleted the battery trying and had to charge it. I confirmed spark on all 6 spark plug cables. I also drained the tank and added 5g fresh gas. I hear the fuel pump activation and fuel drips when I unplug the line at the rail. I plan to test fuel pressure and compression as soon as I get the test equipment. thoughts? Link to comment Share on other sites More sharing options...
89 MJ Posted February 19, 2021 Share Posted February 19, 2021 Sounds like the timing could be off, but I'm not sure how. That was an issue with my blue truck when we swapped the motor--the timing was 180 degrees off and it wouldn't start. Link to comment Share on other sites More sharing options...
86customanche Posted February 19, 2021 Author Share Posted February 19, 2021 Update... I tested fuel pressure and it registers 40 psi while cranking. And turning the key to activate pump doesn’t register, and immediately after cranking it drops back to zero. Link to comment Share on other sites More sharing options...
jdog Posted February 20, 2021 Share Posted February 20, 2021 You might have a bad injector that's stuck open Link to comment Share on other sites More sharing options...
86customanche Posted February 20, 2021 Author Share Posted February 20, 2021 And is there an easy way to check the injectors? Speaking as a novice....... Link to comment Share on other sites More sharing options...
jdog Posted February 20, 2021 Share Posted February 20, 2021 pull the spark plugs see if one looks wet. Are they original injectors? Ohm out each injector, they all should be about the same resistance Link to comment Share on other sites More sharing options...
86customanche Posted February 22, 2021 Author Share Posted February 22, 2021 A few of the plugs looked wet. Injectors 1-4 all ohm’d ok. Pita to get to 5&6. I cleaned an old set of plugs and tested them, then installed them and it started fairly easily. pic is of plugs removed. Link to comment Share on other sites More sharing options...
jdog Posted February 23, 2021 Share Posted February 23, 2021 So it started and ran? Those plugs are fowled out, looks like your running rich Link to comment Share on other sites More sharing options...
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