davehoose
NAXJA Forum User
- Location
- watertown ny
My 89 jeep 4.0 aw4 has had some strange problems, all of which I thought were solved only to come back with a vengeance. I purchased it in December as gift to my wife but drive it much more than her because i had reliability issues and have her drive my 02 ram instead.
To make a long story a little shorter, the 4.0 (renix) was running rich and blowing mufflers off from backfire. I replaced the 02 sensor (precat) and it ran okay for about 2 days. I found the heat sensor (probably wrong term) that is in the manifold literally melted and replaced that. again, was alright for a couple days. i changed the fuel pump and same deal. finally, i checked the tps, which came in at 4.6 volts and adjusted to 82% for the other leg (end, whatever it's called) and it ran better. Actually, it ran really well off and on. I realize it's supposed to be 5 volts, I am hoping financially this is not the problem. Does anyone have any ideas? It's still backfiring intermittently. It will run really well and then putt or backfire. My next guess is the cps, though I am sick of changing parts. It is running rich even when it runs great. What sensor or part would cause this rich running? And if it is running rich is this why I am getting backfire? My third muffler is on now (my first one was put on at a muffler shop and replaced once free, I paid for the third one and put it on myself.)
I read someone Else's post that said they were good with the tps at 4.6 volts. Can anyone confirm this to be true or is this the root of all my problems?
just some technical info: it's a 89 xj laredo with only 96000 on the odometer, auto, air, cruise, 4.0 liter, new fuel pump, screen, fuel filter, precat 02 sensor, manifold temp sensor, thermostat, after cat exhaust, plugs, wires, rotor, cap, air filter, and of course oil change. The cruise control does not work.
The tell tale sign that it is about to buck or skip is the tachometer goes buggy, i.e., it shows zero rpms even thought it's running. When I see a steady tach it runs fine. The speedometer starts acting up also, which lets me know it's about to run bad.
Any clues would be appreciated.
To make a long story a little shorter, the 4.0 (renix) was running rich and blowing mufflers off from backfire. I replaced the 02 sensor (precat) and it ran okay for about 2 days. I found the heat sensor (probably wrong term) that is in the manifold literally melted and replaced that. again, was alright for a couple days. i changed the fuel pump and same deal. finally, i checked the tps, which came in at 4.6 volts and adjusted to 82% for the other leg (end, whatever it's called) and it ran better. Actually, it ran really well off and on. I realize it's supposed to be 5 volts, I am hoping financially this is not the problem. Does anyone have any ideas? It's still backfiring intermittently. It will run really well and then putt or backfire. My next guess is the cps, though I am sick of changing parts. It is running rich even when it runs great. What sensor or part would cause this rich running? And if it is running rich is this why I am getting backfire? My third muffler is on now (my first one was put on at a muffler shop and replaced once free, I paid for the third one and put it on myself.)
I read someone Else's post that said they were good with the tps at 4.6 volts. Can anyone confirm this to be true or is this the root of all my problems?
just some technical info: it's a 89 xj laredo with only 96000 on the odometer, auto, air, cruise, 4.0 liter, new fuel pump, screen, fuel filter, precat 02 sensor, manifold temp sensor, thermostat, after cat exhaust, plugs, wires, rotor, cap, air filter, and of course oil change. The cruise control does not work.
The tell tale sign that it is about to buck or skip is the tachometer goes buggy, i.e., it shows zero rpms even thought it's running. When I see a steady tach it runs fine. The speedometer starts acting up also, which lets me know it's about to run bad.
Any clues would be appreciated.