[kingfish]

Specs:
1990 XJ with 283,000+ miles.
4.0 Auto

The symptoms:
Cruising down the highway the engine will just die. Not like it is out of gas but as if the key is turned off. It does is more under load and all the time with the AC on. If I can catch it before my speed drops too much I can shift into 3rd and press the gas petal and it will catch. Sometimes I can shift to neutral and restart it and rev it to 4000 and it is fine after that.

If I keep it above 3000 RPMs it will keep running but sometimes have to feather the petal. I can floor it and it is fine. If it does die and I can't maintain RPMs (around town) then it will not start back. It will crank and start but the RPMs go to 2500 and then it just dies. Sometimes I can get it to keep running but it stubles very badly. If I let it sit it will start just fine.

It does not seem to ever do it when it is cold. It may be something getting hot but just don't have a clue.

I doubt it is the CPS because it will always start but then die again.
I doubt it is a fuel pump issue because it will fun at high RPMs.

Thoughts? I can't just start throwing parts at it. It is a really weird issue though.

[kingfish]

Well, just an update.

First of all let me say that if you have Verizon cell service or are thinking about getting it you must get the roadside assistance program. $3 a month. It only covers a 10 mile tow but I had the truck towed 2.5 miles today and did not even have to sign anything. Verizon took care of everything. You get 4 occurrences a year.

I had to drive all over town today and it was quite hot out. Truck did it's thing which it does not normally do in town.

One thing I noticed by accident was that when it started to dye and I turned the key to start it would fire again immediately. This leads me to believe it has to be an electrical issue.

At one point today it did not start at all. I am going to change out the CPS this weekend unless anyone else has a thought.

[kingfish]

Well, CPS did not resolve the issue. And there is another develpment. When the truck does run it has a very high idle...~3000rpm. Was doing it before I replaced the CPS.

If it does stay started and idle (at 3krpm) as soon as I shift into gear it dies. Sometimes it will run fine (at the high idle) and I will be at a red light and when I hit the gas to take off it will die.

This is just so weird. There is preassuere at the fuel rail, and it will run at high RPMs all day. I don't really hear the fuel pump though.

I just don't know where to go from here. The thing is, this is my only vehicle and I don't know anyone here. Have to take a cab wherever I go and that is getting really expensive. I had planned on parking the Jeep next year and can't afford another vehicle right now. Unless someone has something for $100-200 around Atlanta.

[jeeptown]

Try cleaning the throttle body, especially the IAC motor. They can get carboned up and cause very similar problems. When was its last tune up? Air filter, plugs, cap and rotor?

[kingfish]

Originally Posted by jeeptown

Try cleaning the throttle body, especially the IAC motor. They can get carboned up and cause very similar problems. When was its last tune up? Air filter, plugs, cap and rotor?

Hmm...Throttle body. Yeah, that could do it. That could be why it will run with the petal all the way down. That could also cause the high idle issue and why it will die under load more often and also why it never acts up when it is cold.

I feel like a real dope to not think of that. I will work on that tomorrow evening. And it is due for cap and rotor...I did shine them up at one point when I was on th eside of the interstate. Wires have not been on too long. I will replace cap and rotor tomorrow too.

Thanks so much.

[kingfish]

Well, cleaning the TB, IAC, new cap and rotor did not resolve the issue. It ran a lot better but after 2.5 miles on my drive home in the afternoon it died.

I am not 100% sure I cleaned the hole for the IAC very well. I am going to try unplugging the IAC when it is cold and see if that will do it. I did go out just now and started it and unplugged the IAC and it kept running. My current working theory is the IAC is sticking when it is hot. Friday evening after coming down a hill and as soon as I stepped on the petal it died.

I am going to keep trying on this thing. I am pretty determined at this point. I just can't recreate the issue on demand...It only does it after driving a while....And in the afternoon.

[kingfish]

Well, unplugging the IAC did not fix the issue.

I have to think about my next step. Trying to think about this logically but I am really starting to hate this. It is just so weird. I can make it 2.5 miles to work without any issues but everyday on the way home it dies about 2 miles from home.

[lyleorszulak807]

I have a similar problem with my 89 XJ 4.0L auto, ive already replaced the fuel pump and relay and the CPS. Mine dies on me while driving for no apparent reason, has not happened on freeway yet just streets.

scenario: I will be driving and the jeep just dies on me, first though wire chaffing/wire issues. Then it died on me while going down a straight road with no bumps. When i restart sometimes it gives me a nasty idle and pushing the pedal doesnt help. after a few restarts its back to normal until the next time.

good luck.

Lyle

[kingfish]

After looking over a few hundred posts and websites I am starting to think an ASD issue but not sure what direction to take...Is there a way to bypass the ASD system? If it was a constant no start issue, that I could deal with but this is driving me nuts.

[kingfish]

Ok, after looking around some more I came across a post describing an issue with an XJ starting and running for a few seconds and then dying....Which is a symptom I am having when it decides to quit.

Someone suggested the Balast Resister on the drivers side fender. I just went out and looked at it and I could not find it....It was not on the fender wall anymore, it was laying under the airbox. The connections were very corroded and one of the wires going in looked a little melted. I bypassed the resistor and am going to give that a shot. It does fit the symptoms also and I heard something I had not heard in a while...Relays clicking. This could also explain why the issue only happens when hot...The wire was laying on the wheel well and when the metal gets hot it softens the plastic on the connector and may be shorting out the wire. When it cools the plastic hardens and no more short. Even without a short or the resistor going bad, all the corrosion could explain why the symptoms have been getting worse and why it usually always stalls with the air on. Assuming I make it home I am going to drive it around the apartment complex with the air on and see if I can make it stall.

[kingfish]

!!!!!!!!FIXED!!!!!!!!

When I heard the fuel pump kick in when I went to start the Jeep I knew I was looking good.

Jeep ran GREAT all the way home. I pulled into my apartment complex I took a deep breath and turned on the AC. Drove around a while and not even a stutter.

Thanks to those that offered advice and to the others who wished me luck.


So, it took 8 months of head scratching, many posts online, hours of reading, months of tinkering, many hours on the side of the road, 2 tow truck trips, about a hundred bucks in taxis, a very short piece of wire and most of all a VERY patient girlfriend and it is fixed!!!!!!

[myriad360]

Way too go kingfish, I dunno why but this is the first time I saw the thread. Sorry we could not help more! I am glad it is running again for you.

Also, here is all the info for the Renix Fuel Injection, I hope it helps in the future. Take care.

[Crystalship1]

Awesome!!

And yeah..... I got the same coverage.

Covers any vehicle you in or ON as long as you've got your phone.

[jeeptown]

Good job Kingfish!! It always seems to be the so called 50 cent piece that ends up breaking. So it was the ballast resistor to the fuel pump? I have also heard of this condition before but never experienced it.