goldenlandscaping

Ok bought a 1992 2 door xj sport... when in gear runs rough but pretty good... but put it in gear sputters and backfires rapidly til you go down hill then revs all the way up...
Replaced the following....
fuel filter
fuel pump
fuel rail and injectors
throttle body
distributor
plug wires
What could it be??

goldenlandscaping

Can anyone help me?

goldenlandscaping

Nobody can help me?

CodeXJ

Did you mean it runs fine out of gear, but in gear it sputters? Because your first line says it runs fine in gear then says it runs bad in gear, so I'm a little confused.

When you say you've replaced the distributor, did you mean just the cap, or the entire distributor assembly? If so, you may have indexed it wrong. If you just did the cap, did you do the rotor too?

You replaced the throttle body? Why? Did you take the sensors/IAC from the old one and put it in the new one, or did you get new sensors? If this is a junk yard or used unit, you should probably remove the IAC and clean everything.

I've heard O2 sensors can cause this, but I've got no real experience with bad O2 sensors. It sounds like you've just been throwing parts at the problem, though. Have you done a compression test yet?

I noticed you said plug wires but not spark plugs, did you just forget to include those? Are they gapped correctly?

goldenlandscaping

meant in idle it runs pretty well
just got plugs today and was fixing to try that the sensors are from my parts jeep they are fairly brand new i replaced them on it before it died

CodeXJ

Parts Jeeps are awesome.

Idle is OK, but under throttle it sputters? I'd say Fuel pump or a clogged fuel filter, but you said you replaced that? Maybe get a pressure tester and see what kind of fuel pressure you have?

goldenlandscaping

Changed the plugs like you mentioned got ready to start it nothing...
started looking around for blown fuses...none
start looking under the dash and their is this little box not in my other jeep and they are basically the same pull it out without unplugging anything and it says on it super IPS Alarm system by clifford
as well as their is this little red light lit on the dash i know doesnt go there i had investigated the red light as well as something called a magnetic resonance sensor by the battery but i main concern was getting it to run so hadf not really paid too much attention to it so now im stumped the starter is not even activating had hooked the stereo back up and i can tell you the original owner is no longer with us and he was the only driver and a mechanic

goldenlandscaping

But I really need some help I hate having to XJs in my friveway and not being able to drive either one

CodeXJ

An alarm?

Oye, hope you didn't somehow trigger an ignition lockout.

AvidXJ

My jeep had a similar problem as yours. It would idle fine but consistently sputter when in gear. When this happened to me i started by changing the fuel pump and filter since my pressure was low but that did not fix it. My problem turned out to be the o2 sensor as someone mentioned above. It was a frayed wire on the upstream sensor (before that cat) that caused the fuse for the o2 sensor heater to consistently burn out. This causes the sensor to misread and the CPU thinks its running rich and will lean out the fuel mixture which causes it to sputter. I cant guarantee this is your problem but it sounds very similar to what i was experiencing. I would try changing the o2 sensors and checking all the wiring as well as the fuses associated with them. Good luck with your problem. Let us know how it goes.

goldenlandscaping

pulled the fuse i changed for the alarm thingy and now it turns over and runs but same issue is there a diagram for the above mentioned o2 sensors? so i know where each one is

AvidXJ

Well i dont have a diagram but here is a description and some pictures of them. Both o2 sensors are on the exhaust. the upstream is closer to the engine and directly below the oil pan while the downstream is a bit further back right after the catalytic converter. The o2 sensors are screwed in and their wire is about 3 ft in length and has a connecter at the end. The issue on mine was caused by the upstream o2 sensor wire being frayed and causing the sensor to short out. You will have to get under the car to see them (at least in my jeep). the upstream you will see if you look at the exhaust pipe where it is vertical on the driver side of the engine. O2 sensor is towards the front of the car in this pipe. For the downstream just follow the exhaust back till you get to the catalytic converter and you will see it plugged in right after it. Good luck. If any of this is hard to understand it probably my fault....just let me know and i will try to clarify

goldenlandscaping

Nope makes sense to me i will check them out and let you know

96_xj

You also need to take a look at your CPS. It is located on the bell housing-driveside-top. This can cause ALOT of issues and are known to "gradually" fail. If it were a fuel pump issue it is either it works or it doesnt about 99% of the time. Take a fuel pressure reading and see what you get. it may be a clogged filter-its almost always neglected.

Good advice on the o2 sensors. Mine did the grounding out on the upstream one too, but if that fuse blows/pops then the vehicle will not run at all. But the o2 sensor will cause rough running, or a to lean/to rich issue. but it should throw a code....


Next thing to check is your MAP sensor. i had an issue few weeks ago when going from 4000 feet to 9000 feet in a 16 mile uphill. Once i got to the top and shut the vehicle the map sensor did not take into account the thinner air right away so it cause it to run to rich and run like crap(once it did run) and then once the map sensor adjusted to the thinner air all was well...

kojoff

When my CPS (cam position sensor) went out, my BEEP just up and died. Never sputtered or anything... running one second, not the next.

The O2 sensor thing sounds like the problem to me.