Random Stalling (long)

Hey guys, I'm at whit's end and I need your help. I've got an 88 XJ with an auto-trans.
Last night, it began stalling out on my way home from work. I was in rush hour traffic, but I was able to start it right back up. It did this three or four times and each time it got harder to restart. I noticed the gas light came on just as it stalled or right after it stalled, but it had over half a tank of fuel. I was able to get it to run long enough for me to get to a gas station and I filled it up. After I filled it ran fine for until I was almost home and started stalling out again. I was able to make it home.
I checked the vacuum lines and visible electric connectors when I got home; I saw nothing out of place.
A little history at this point, this Cherokee has the fuel pump wired to a switch on the center consol by the previous owner. He said it would start. But not stay running. I figured it was a bad ballast resistor, but would fix it sometime down the road. To get this inspected this past summer, I had to replace the exhaust from the cat back. I had to replace the O2 sensor and gave it a tune up. Any way I checked all of this wiring for the fuel pump and it all looked OK. So I got in it and it started right up. I drove it around the block and it ran fine.
So this morning I get in to drive it to work. It starts right up and I’m on my way. I again figure I will check things out this weekend and a way I go. I get 20 to 25 minutes into my commute and it stalls. I was able to get it to the side of the road and it starts right up. I let the engine run a few minutes in park and it seems fine, so I get back under way. I few blocks down the road it stalls and then this time I'd have a horrible time getting it started again. It is strange in that when I crank it, it starts up, revs to about 2500 rpm and then dies, without me touching the gas pedal. I try to pump it and as it dies it sounds like a motor that has the choke closed. I just had it towed home and asked my wife to start it up (I’m working ). She said it started right up and she drove it into the garage. Any ideas where to start?

Sounds like some sort of fuel delivery trouble. Maybe the fuel pump is flaking out. Those symptoms were the same as when I almost ran out of gas. I'd check the fuel pressure while it running and when it dies to see if there is a loss in pressure. But then again it could be a number of things....gotta love electronics! Good luck....sorry you can't be with us tomorrow for rattlesnake/constrictor.......unless you get it fixed.

Brett

If it's fixed I will at least be there to watch.

Update on Random Stalling

Update. I went out to work on it this morning and it had a very strong fuel smell. I could not find a leak anyplace, so I am going to replace the fuel pump and ballast resistor. (I checked it this morning and the resistance shows it opened, max resistance.) This way I can put it back to stock wiring and go from there. I will keep everyone posted to what I find.

A bad CPS can cause exactly the same stalling and hard restart symptoms as you describe so you might wanna check that out as well.

I rewired the fuel pump and replaced the ballast resistor. I then replaced the fuel pump and also changed the fuel screen. I was surprised that the screen was so clean, probably did not need changed, but I had already bought it anyway. The fuel pump ran without the switch, so one problem fixed, but after about 20 minutes of running around the neighborhood, well it did not fix the problem. As you suggest Dr. Dyno, the CPS is next in line for replacement.

OK guys back to the top. I have replaced the fuel pump and the CPS. I drove around for about an hour last night and just as I was getting by in my subdivision it started stalling again. When it stalled, it would be very difficult to restart. I let it sit for about 5 minutes and it started up and ran for a few minutes. I had to do this the rest of the way home. This morning it started right up, but I left it in the garage and drove my Geo. Any other ideas?

Check compression on all cylinders. Bet you have little compression on one or more....

Rocketman said:

Check compression on all cylinders. Bet you have little compression on one or more....

Click to expand...

I do have a rod that is knocking and lately it has been getting loader. Could it be related?