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Hello all! Running into an issues on my 1990 2.5l tbi std shift wrangler and need some help. First a little background. I was in the middle of a full rebuild when I had to relocate, so my brother back in Ohio is completing the rebuild. He put the fully rebuilt and assembled (by machine shop) motor in. I bought every sensor on the motor to replace, as well as new injector. Everything on the motor is new except the fuel pressure regulator and intake. A year ago I put a new fuel tank and pump/sending unit and filter in also.

Now the problem.....My brother has everything together. It fires right up and idles great. When he is easy on the pedal it runs fine, but when he really gets on the Gas hard it falls on it's face. He has checked the timing per the manual a few times and it's good. When he puts the timing lite on it while running he is at 11 degrees before tdc, which if I remember correctly was what it was at prior to the teardown. He is stumped.....hes a Ford guy so this is his first jeep motor....and I am fairly ignorant (most would agree strongly). He does not have a fuel pressure gauge to check it (he was going to check AutoZone borrow a tool deal this week to see if ones avail). Any suggestions would be greatly appreciated!

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I think you and your brother are on the right track, Aspenyj.  The symptom sounds like either fuel starvation or an ignition issue.  My first angle would be fuel, and a pressure regulator port test would give you the fuel pressure answer.  You also need to verify that the fuel volume is sufficient.

The best tester has a Tee with a valve for checking fuel flow volume with the engine idling.  Make sure you run the fuel into a safe (grounded) metal container for the fuel volume test.  This approach should be conclusive.  If the volume suffers, consider the fuel filter as a possible trouble spot if you're confident the tank pickup sock and pump are okay.

To be continued...Let us know what you find.

Moses

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Ok....update....last week out of the blue the Jeep started starting real hard. Then my brother put in the new fuel pressure regulator. He went and got a FP gauge and tested 14lbs while running. Then he tried to test the pressure when you first turn the key and hear the fuel pump cycle...he got nothing. He double checked that it was cycling on, again, but no FP read immediately after it cycled (this is all before turning the key all the way to start). He pulled the filter just to check it was not plugged (only an hour of run time on it since new). He said he was going to get underneath it and check electric connectors tomorrow. He said he has run into a similar issue on Ford rangers and it was always a Fuel Pump relay, and some times a bad\dirty\corroded connection, but YJs don't have a fuel pump relay corr? He was also going to check voltage at the pump.

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Get ready for this.........it was any completely out of gas. Evidently my new(only 250 to 350 miles on it) sending unit was shit. Brother put gas in it and it fired right up, idled perfectly. He then took it out on his gravel drive after it warmed up and mashed the gas and had the tires spinning thru 3rd. He called me to criticize me for buying cheap parts.....ha ha ha. He was headed back out to make sure it started fine and to double check the 4wd worked fine since he had to tear into it to replace axle seals. It always seems to be something stupid! 

 

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I'd enjoy that!  Aspen is fun...You have the right vehicle for the venue!  I've spent time at the 14'ers with the original Camp Jeep events at Camp Hale, 4x4 media launches (guiding at the San Juans), All-for-Fun events and other Colorado outings.    Once you can depend upon the YJ, you'll have a great time...Post photos when you get rolling!

Moses

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