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Discussion Starter · #1 ·
I don't get it. My TJ was running great with two year old ignition components but had a slight rev issue at idle. I decided to do a full tune up with quality parts. Afterwards the jeep runs harder and idles like a lawn mower. Gas mileage is "ehh", barely getting 200 miles out of a tank.

My XJ has four year old ignition components. I wanted to tune it up so the lady has a reliable mode of transportation. I did the tune up along with replacing the 02 sensors and CPS. The old plugs had a gap of .05, geez. Before the tune up the jeep idled like a car, you could barely feel it running. After the tune up the jeep feels like it's missing very lightly and it's not a smooth idle. I can't even get 200 miles per tank now. My 2nd tank after the tune up was 187 miles.

I drive on a highway at 55 mph twice a day. Not much else.

:confused:

These jeeps gotta be messing with me or something.
 

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Seems about right!

Your engine ECM has made friends with all your engine, fuel and ignition components. Having spent many years in joyous harmony they have become a "well oiled machine". But now you have busted up the group and replaced them with all new playa's. And since the conductor (your ECM) doesn't know the range of abilities of the new orchestra, he is trying to make the new guys fit the mold of all the old guys. :(

Try unplugging the battery cables, touching them together for about 30 seconds and then reconnect them. This will reset the ECM to the factory "minimum" specs, and then the ECM can begin relearning the sensors and develop a map to make them work together as efficiently as possible, and ultimately make your engine sing!! Woot Effing Woot!
 

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^ x2

it will take about 30 to 40 start cycles before its back to old faithful
 

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Exactly what they said. Had to do that a couple times with my swapped injectors.
 

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Discussion Starter · #5 · (Edited)
This is interesting because I did many tune ups on the xj, tj, and previous tj, and never had to restart the ECM. The jeeps would go on and do their daily duties like nothing happened. This time around I get strange symptoms that I've never had to deal with before. Maybe it was the 02 sensors and CPS that triggered the confusion.

After getting only 76 miles in a half tank of gas today I decided to do what you guys suggested.

I just went out there in 11 degree weather and disconnected both batteries and touched both cables for 30 seconds. The XJ gave me a hard time cuz both cables would not reach each other so I used a piece of metal to contact em both. Typical XJ behavior, not cooperating with me. (sigh)

We'll see what happens in the next few weeks.
 

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Discussion Starter · #6 ·
Seems about right!

Your engine ECM has made friends with all your engine, fuel and ignition components. Having spent many years in joyous harmony they have become a "well oiled machine". But now you have busted up the group and replaced them with all new playa's. And since the conductor (your ECM) doesn't know the range of abilities of the new orchestra, he is trying to make the new guys fit the mold of all the old guys. :(

Try unplugging the battery cables, touching them together for about 30 seconds and then reconnect them. This will reset the ECM to the factory "minimum" specs, and then the ECM can begin relearning the sensors and develop a map to make them work together as efficiently as possible, and ultimately make your engine sing!! Woot Effing Woot!
For some reason I really like this explaination. :rofl:
 

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For some reason I really like this explaination. :rofl:
Seems about right!

Your engine ECM has made friends with all your engine, fuel and ignition components. Having spent many years in joyous harmony they have become a "well oiled machine". But now you have busted up the group and replaced them with all new playa's. And since the conductor (your ECM) doesn't know the range of abilities of the new orchestra, he is trying to make the new guys fit the mold of all the old guys. :(

Try unplugging the battery cables, touching them together for about 30 seconds and then reconnect them. This will reset the ECM to the factory "minimum" specs, and then the ECM can begin relearning the sensors and develop a map to make them work together as efficiently as possible, and ultimately make your engine sing!! Woot Effing Woot!
As do I...
:eek: Just keeping in real, Brudda's
 

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Discussion Starter · #9 ·
Well seems like it's working. It's idling better, not perfect, but close. My gas gauge stopped moving and been at 1/2 tank both ways to and from work. :thumbsup:

Hopefully I net 22,300 miles per tank.
 

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Itll run a little better after a few startups and run cycles.
 

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I chuckled a little at the title since it seems like you are going through something similar with your truck now. Tune-ups just don't go well for you eh Mudd?
 

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Discussion Starter · #12 ·
I chuckled a little at the title since it seems like you are going through something similar with your truck now. Tune-ups just don't go well for you eh Mudd?
Obviously not. :LOL:
 

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I don't get it. My TJ was running great with two year old ignition components but had a slight rev issue at idle. I decided to do a full tune up with quality parts. Afterwards the jeep runs harder and idles like a lawn mower. Gas mileage is "ehh", barely getting 200 miles out of a tank.

My XJ has four year old ignition components. I wanted to tune it up so the lady has a reliable mode of transportation. I did the tune up along with replacing the 02 sensors and CPS. The old plugs had a gap of .05, geez. Before the tune up the jeep idled like a car, you could barely feel it running. After the tune up the jeep feels like it's missing very lightly and it's not a smooth idle. I can't even get 200 miles per tank now. My 2nd tank after the tune up was 187 miles.

I drive on a highway at 55 mph twice a day. Not much else.

:confused:

These jeeps gotta be messing with me or something.
I got o2 censors for orielys and they gave me Californian o2 censors which completely screwed up how my xj ran. Make sure you got the parts you ordered. Other than that just give it time and it should adjust itself.
 
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