88 4.0 Running like crap

This all started about a months and a half ago. This is a trail only rig so I only drive it on the weekends.
About a month and a half ago my XJ started running like crap, I suspected water in the fuel because I knew I had a small pin hole in the top of the tank.
I drain all of the fuel with the factory pump and refilled with new fuel and it ran great. About a week or 2 later it started running like crap again, dying, no power etc. It would sputter, back fire and in my opinion it sometimes smelt like it was running rich. I limped back to the trailer and went home and parked it. A week later I start it on the trailer and it seams to be running like a top, wtf??
I beat this thing hard and do not take care of it. Does any one have any suggestions??

Thanks a Million

-=PEAKABOO=-

-=PEAKABOO=- said:

I beat this thing hard and do not take care of it. Does any one have any suggestions??

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I think you might have answered your own question. Take better care of it and it'll take care of you.

Seems like you have a fuel issue. Possibly a clogged up filter, dirty throttle body, injectors etc. Run some Seafoam through it (1/2 in the TB and 1/2 in the tank). Then change the filter. Did you fix the hole in the tank? Could be your pump if you found or suspect water got in the tank

i only drive mine on weekends.. but anyone knows a wheelin rig requires alot of maintenance.

want a car that can take a beating? buy a honda. they wheel nice

Not saying I totally neglect it, I do normal maintenance. I have never changed any sensors. As far as beating it up I can assure there are far more nice XJ's out there then there are as beat as my junk:gee:

Don't get me wrong, I'm not trying to tell you what to do, but you should look deeper in to your problem even if it's just a trail rig. A trail rig running like crap can leave you stranded 20 miles from the nearest pavement.

"=Running like crap=" can be a complicated and expensive mess or something as simple as a bad ground, a new O2 sensor, MAP sensor, or vacuum leak (or just a good all' round tune-up). If you know your systems are tight you can strap on a couple of extra gas cans and go for it.

Also, familiarize yourself with a Digital Multimeter (not expensive), since yours is an 88, most electrical and sensor diagnosing can be done with this tool. Spark and fuel issues can be solved with some really simple snooping and you can wheel past guys trying to figure out the error codes on their OBD I and II rigs for days.

Your (our) RENIX Jeeps are simple compared to some of the later models with power everything. Start with a good scrub-up in and under the engine bay and take it from there.

I hear ya. I am familiar with and own good multi-meters both analog and digital, I am an electrical contractor
I am also very familiar with 4.3 fuel injection (OBD1) as my buggy has a 4.3 in it and built the harness but I will be the first to admit that I am clueless to the renix 4.0 electrical system because I have never had an issue that a wiggle test did not fix in 6 years of wheeling this junk 3 times a month. I am all ears about also, I am hoping someone can go "Hey mine did that and this was the problem"

Once again I am all ears and thanks again for any help.

-=PEAKABOO=-

I'd say check fuel pressure, and make sure it's not a bad fuel pump or clogged fuel filter. Then check the sensors. lunghd.com has tech write-ups on checking all the renix sensors with a multi-meter.

I will check fuel pressure. I have a fuel pressure gauge.
Thanks for the link

Is it running like crap at start up or after she's warmed up a bit? My 94 when I first got it would run normal when I first cranker her up. Let her get to normal operating temp and she ran so bad I don't know how she stayed running. Ended up being the fuel pump for me. I second checking the fuel pressure.

I will check fuel pressure later. I know last night the jeep was running great in the driveway, I could not get it to run bad in the driveway.

One great way to cure a lot of bad sensor signals to the computer is to install a HEAVY ground wire from the block to the firewall and another from the negative post of the battery to the front clip.....jeep is famous for bad grounds...I think 5-90 sells a ready made kit.

egr valve may be hanging up or the egr transducer is shot