wtf is wrong with my 4.0

[435Mj]

Ok I recently got a 89 mj with 156000 on the gauge. It was runnng real rough,had no power and missed real bad. I did alot of tune up things to it-engin flush off the bat, oil change and lucas oil stabilizer,new plugs,wires,cap,rotor and distributer gear, new vacuum lines, pluged some others,remove vacuum disco lines and pluged, new map and tps sensor,k&n cone and flowmaster cat back(minus the cat), swaped injestors from my 93 xj into mj, new fuel filter,strainer bag,red top and fixed battery cables.

Everything I did has made it run better.

My problem is this, in the morning after starting the mj misses and kinda sputters a bit on acceleration. It never gets close to dieing or anything, but struggels a bit. Furter into the day it starts running better but still misses or sputters a little. I feel that im not getting the full power out of the engin and seems to be consuming fuel pretty fast. Ohh and it has and eratic lifter tick at slower speeds, when doing 60 it sounds smooth.

If anyone has had this type of problem please post up what you did to fix it. thanks tim

 

[ChevelleSSLS6]

I'm not sure if this would help or not, but are your pluggs gapped or were they installed 'out of the box'?

 

[lawsoncl]

I didn't see O2 sensor on your list. You measured the resistance on the coolant sensor to make sure its reading right? Either one would make it run crappy and give you poor mileage. The one for the computer is on the drivers side of the block below the exhaust header. A cracked exhaust header sounds a lot like a lifter tick and gets better as it warms up. Pretty common to crack at the collector.

 

[xjtrailrider]

There are a bunch of good threads on here for the RENIX system. Your problems could be anything from a faulty EGR to a bad ground/connection.

 

[winterbeater]

What is your cyllinder compression? What do your spark plugs look like (black & oily, white, light tan)? Before doing extensive work on a motor that isn't running good, it's always a good idea to assess the ability of the rings and valves to provide compression.

 

[magimerlin]

You said you replaced the TPS sensor but did you adjust it right, or at all?
This site has helped me out in the past as far as sensor issues go...
http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

 

[435Mj]

thanks for the replys.
1. the plugs are gaped but used
2. Ill get a new o2 sensor
3. I dont have a compression gauge, but Ill look into getting one and how to do it
4. Ill check the EGR and ground. (how do i tell if it is bad?)
5. strong possibility it has a cracked header like my 93 xj, but it sounds diffrent.
6. Ill try adjusting the TPS...it dose idle high

keep up the ideas thanks tim

 

[435Mj]

You said you replaced the TPS sensor but did you adjust it right, or at all?
This site has helped me out in the past as far as sensor issues go...
http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

Great resource man. I guess i know how to check the sensors now.

 

[winterbeater]

thanks for the replys.
1. the plugs are gaped but used
2. Ill get a new o2 sensor
3. I dont have a compression gauge, but Ill look into getting one and how to do it
4. Ill check the EGR and ground. (how do i tell if it is bad?)
5. strong possibility it has a cracked header like my 93 xj, but it sounds diffrent.
6. Ill try adjusting the TPS...it dose idle high

keep up the ideas thanks tim

You're going to test the o2 sensor first, right?:looser:

 

[435Mj]

yes im going to be going through all of them. testing them at the shop tomorrow. and yanking them off the cherokee if needed or buying new on monday when im not poor. thanks tim

 

[ParadiseXJ]

The good news is there's only one(1) O2 sensor on your model. $55 Bosch. AutoZone.

 

[Onetype]

have you checked the timing?

 

[435Mj]

have you checked the timing?

Yes I did, it was jumping and changing 4 to 6 degrees at idle. so i checked my distributer and the gear had alot of play so I replaced the gear. now the timeing is steady. As far as I can tell there is no way to adjust timeing on the 89, I didnt see anything in the repair manual either. The timeing mark is hitting on the higher side of the timeing plate if that means anything. thanks tim

 

[joe_peters]

Is your engine reaching normal operating temperature, i.e., thermostate working properly and of 195 degree type?

 

[Red90Laredo]

good luck toke!

 

[435Mj]

Is your engine reaching normal operating temperature, i.e., thermostate working properly and of 195 degree type?

Im not sure. This mj has dumby gauges, none of the lights are going off. But im used to my xj gauges that you can actully read and know where you stand. I can scan it tomorrow and get the temp.

why do you ask?

thanks tim