I’ve read some of the stuff on here regarding fuel starvation. Quick background - last summer I bought a 1990 yj 4.2 258 w nice body and frame and it ran. Got it home and it started having issues. Hard starts stalling at stops hesitating and misfiring. Ran ****ty all summer as I made her my own. First three months I focused on some minor body stuff (eliminating rust, touch up the body and Bedlined it).
Anyway Winter came and I used the time to put in a new starter solenoid and I cut out the ignition control module and ECM and converted it to a CRT HEI distributor and Motorcraft 2100 carb. Eliminated hoses and vac leaks. Now she starts and runs without stalling. But it had a “skip-misfire-hesitation” type issue that’s intermittent. Took it to a real mechanic (I am not at all - just a guy who can follow instructions on you tube etc). He found another vac leak and timed it. Got a sticky valve unstuck. But the intermittent hesitation and bucking stayed. But it can present normal on a drive.
soooo… reading up here I have several thoughts but I don’t know which to pursue and in what Order so as to troubleshoot smaller cheaper fixes first and work my way up to bigger more expensive fixes last. The main symptom is clunking bucking hesitation under drivers feet with an occasional pop from near the carb mostly in 3rd and 4th gear under heavy acceleration. Im convinced it’s a fuel starvation thing.
Could the wet float level be too low?
Could fuel lines be clogged
Gummed up sock/dirty crud in tank
I’m pretty sure assume mechanical fuel pump is fine bc it runs ok a lot of the time and it spouts fuel.
my mechanic mentioned maybe deleting the fuel return to get a little extra gas to the carb under high demand???
The jeep is currently in the shop but if they can’t figure it out I’m gonna have to go through some sort of progression. So what I’m asking is what order to trouble shoot and eliminate possible culprits and what needs to be done diagnostically the old school way (no code reader) to figure it out
Anyway Winter came and I used the time to put in a new starter solenoid and I cut out the ignition control module and ECM and converted it to a CRT HEI distributor and Motorcraft 2100 carb. Eliminated hoses and vac leaks. Now she starts and runs without stalling. But it had a “skip-misfire-hesitation” type issue that’s intermittent. Took it to a real mechanic (I am not at all - just a guy who can follow instructions on you tube etc). He found another vac leak and timed it. Got a sticky valve unstuck. But the intermittent hesitation and bucking stayed. But it can present normal on a drive.
soooo… reading up here I have several thoughts but I don’t know which to pursue and in what Order so as to troubleshoot smaller cheaper fixes first and work my way up to bigger more expensive fixes last. The main symptom is clunking bucking hesitation under drivers feet with an occasional pop from near the carb mostly in 3rd and 4th gear under heavy acceleration. Im convinced it’s a fuel starvation thing.
Could the wet float level be too low?
Could fuel lines be clogged
Gummed up sock/dirty crud in tank
I’m pretty sure assume mechanical fuel pump is fine bc it runs ok a lot of the time and it spouts fuel.
my mechanic mentioned maybe deleting the fuel return to get a little extra gas to the carb under high demand???
The jeep is currently in the shop but if they can’t figure it out I’m gonna have to go through some sort of progression. So what I’m asking is what order to trouble shoot and eliminate possible culprits and what needs to be done diagnostically the old school way (no code reader) to figure it out