yj fuel problem

[allabs5150]

87 YJ did a weber conversion about 2 years back. Alot better than the crappy factory set up but the weber is tempermental when it comes to tuning. This past weekend I did a rebuild on the weber carb. The jeep started sputtering a little in lower gears and figured a rebuild might be a good place to start. Sfter all was back together I drove the jeep for over an hour with no problems. Today I start it up it starts fine and idles great. I get about a 1/2 mile down the road and it starts to starve for fuel almost like its vapor locking. It never really stalled and would clear up I'd tear through the gears fine then a few minutes later the same thing. Now the problem seem to be getting worse........Any ideas, or thoughts on what the problem could be. It has a new fuel pump & fuel filter cap and rotor look fine too

 

[Bounty__Hunter]

Best repair for a Weber or Carter is the Motorcraft 2150 in 1.08 size. Reportedly easier to tune and much better at angles. Tons of articles if you google it.

 

[lah2420]

I'm assuming you don't have an electric fuel pump. I put a new pump on my 87 when I did a motor rebuild. It did the same thing as yours. The new pump was bad. I've also seen one with a fuel pressure regulator that didn't allow enough volume of gas to pass to run at higher rpms. It worked fine at lower rpms.
As far as the Motorcraft, I tried one and couldn't get it to run right. It would dump gas in a steady stream while idling. After 2 weeks of messing with it, I put the Weber back on. I'm not dismissing the Motorcraft, I just couldn't afford to waste more money trying to make it run. I think you would be better off to get the one you have running as to spend the bucks on the MC in the hopes it would run.

 

[allabs5150]

Yes I am starting to think it may be a bad fuel pump, but this is my latest dilema.
Friday night with about 1/2 tank of fuel I added a can of dry gas (at this point I am just trying anything) I also blew air in the fuel line froim the fuel pump to the gas tank, thinking something could be plugged up in the line. Bumped the idle up, and it ran great all day Sunday, with only one studder on the way home.
I filled the tank with more fuels sunday night now has about 3/4 tank added one more can of dry gas. The jeep sat about 4 hours I started to go for a drive it started fine but about 1 minute down the road it started it's same fuel problem (almost like its vapor locking)
This thing is making me nuts works fine for a few hours then starts its antics again.
Now I am starting to wonder i there is something in the fuel tank, only because the problem seesm to be worse when there is a 1/2 tank or more of fuel onboard.....is this possible?????? as far as the fuel pump goes. If it was bad wouldnt the problem be more consistant???

 

[lah2420]

Are there 2 lines from the outlet side of the fuel filter? The center one should go to the carb. The one on the edge of the fuel filter should go to a line back to the gas tank I think. Not sure what it is, but I've heard there could be problems if it isn't there. Otherwise, I would still suspect the fuel pump.

 

[allabs5150]

Thanks for the input lah2420. You still feel as though the new fuel pump could be a problem even though the problem occurs intermitenly

 

[LVRockCrawler]

yea... and could be the filter packing up with sediment under pressure and letting go as it starts to die out.. and so on and so on... c/o the filter (had that problem w/several cars / jeeps)