adobson06 Posted September 21, 2014 Share Posted September 21, 2014 Back again guys this time it's a fuel problem was going up a hill it had been bucking for about 40 miles finally it died mid way up the hill it'll start and run for about 10 seconds and die. So I changed the pump fuel pressure regulator vacuum lines etc.... now it'll start perfectly and stay running but has zero power and if you Rev it it almost dies after letting off its also back firing through the throttle body I'm guessing a voltage problem to the pump but any other options would be great to check into Link to comment Share on other sites More sharing options...
86FUBAR Posted September 21, 2014 Share Posted September 21, 2014 Check the voltage to the pump and the fuel pressure! what kind of fuel filter does it have now as the original 2.8 fuel filter setup was in the carb ? Link to comment Share on other sites More sharing options...
Jeep Driver Posted September 21, 2014 Share Posted September 21, 2014 Since you replaced the vacuum line to the regulator, I assume you went to the MPI 2.5? TBI 2.5 requires 14-15lbs pressure and the MPI requires 49lbs (IRRC?) Which pump did you use? The MPI or carbed filter will flow....not worried about that.......but I would not trust the low pressure hosed and clamps at 50lbs. Link to comment Share on other sites More sharing options...
adobson06 Posted September 21, 2014 Author Share Posted September 21, 2014 this was all done before i got the truck i have a copy of the title to the engine its a 2.5 out of a 93 cherokee....... i hooked up a fuel pressure tester first prime its over 20 after that its below 20lbs it also has a filter for a 93 cherokee hooked up i just replaced it actually... and i used a sending unit and pump out of a 93 cherokee as well pump and sending unit are brand new filter is brand new vaccum lines have been freshened up, and the regulator is brand new as well. Link to comment Share on other sites More sharing options...
Jeep Driver Posted September 21, 2014 Share Posted September 21, 2014 Then your pump is shot......you're about 30lbs short of what is needed. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted September 21, 2014 Share Posted September 21, 2014 Agreed Link to comment Share on other sites More sharing options...
adobson06 Posted September 21, 2014 Author Share Posted September 21, 2014 tried old pump in brand new sending unit and tried brand new pump in new sending unit both produced same numbers the ballast resistor does not look healthy though was wondering if there were specs for what the voltage should be at while running so i could see if there is a possible voltage drop while the vehicle is running.... not sure scratching my head on this one may try to replace the ballast tonight and go from there Link to comment Share on other sites More sharing options...
relyt120 Posted September 21, 2014 Share Posted September 21, 2014 just by-pass the ballast resistor to see if it helps, u technically don't need it Link to comment Share on other sites More sharing options...
adobson06 Posted September 21, 2014 Author Share Posted September 21, 2014 alright i'll give that a shot and see if it works thanks for all of the quick answers everyone Link to comment Share on other sites More sharing options...
Rockfrog Posted September 23, 2014 Share Posted September 23, 2014 Never mind, reread again. Clean the plug and test voltage at the plug, the 93 system should be pushing at least 30psi ... more if you disconnect the FPR vacuum hose. May also have a bum FPR or a restricted fuel line. Link to comment Share on other sites More sharing options...
adobson06 Posted September 23, 2014 Author Share Posted September 23, 2014 update on my problem after new pump/sending unit pressure regulator re-running new vaccum lines little over 100 bucks in parts it was the ballast all along bought one for six bucks threw it on and boom problem solved.... :wall: Link to comment Share on other sites More sharing options...
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