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Discussion Starter #1
I have a 1989 jeep cherokee limited with approx 245,000 miles on it. Since we bought it we have had nothing but problems with it. My mileage has never gone over 10 mpg no matter what, it runs really rough, it sputters, stalls, etc well any way to make a long story short we recently replace all 6 of my fuel injectors (one of them was leaking) Now that those have been replaced it is running MUCH WORSE than it did before. My milage had DROPPED significantly, it hesitates worse than before, etc. I did not have the injectors replaced at professional shop. Maybe that's the problem? Anyways the person who replaced them is saying that it is a computer issue and that my computer needs to be replaced. Is that true if so is it worth it? I've looked a the blue book value of the vehicle and it's worth less than a new ecm. Any advice is appreciated.

P.S none of the bells and whistles such as the power windows, seats, etc work either.:(
 

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Not the last time we had it checked which was BEFORE we replaced the injectors
First I would get them checked so you arent just throwing money at a problem but rather narrowing things down a bit.

My guesses:
TPS bad or out of adjustment
CPS bad
o2 Sensors bad
 

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O2 sensor is only a few months old
Well the other sensors that I mentioned may be at fault, also the install could have been bad on the o2 sensors or a number of other things. They are prone to failure.

Still get those codes looked at first.
 

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Discussion Starter #7
The guy I live with is convinced that if I just simply replace the computer that will fix everything that is wrong with it. Will that even help? We found a used computer out of a wrecked 89 XJ that he is urging me to buy. I don't think buying a used computer is a good idea.
 

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Well unfortunately, being an '89 Renix era Jeep, it will not store trouble codes...You can pull some limited live data with the appropriate diagnostic tool. Were the injectors put in the appropriate size injectors, also verify that the injector clips were installed properly, and not crossed with others. Verify TPS and IAC motor is plugged in as well.
 

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The guy I live with is convinced that if I just simply replace the computer that will fix everything that is wrong with it. Will that even help? We found a used computer out of a wrecked 89 XJ that he is urging me to buy. I don't think buying a used computer is a good idea.
1. The computer is a very expensive repair.

2. I would try other things first, an example the sensors I was talking about also checking the codes.
 

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1. The computer is a very expensive repair.

2. I would try other things first, an example the sensors I was talking about also checking the codes.

RENIX HAS NO CODES TO CHECK AND NO PLACE TO PLUG IN A OBD READER. Kyle you know better. Have I taught you nothing?
 

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Discussion Starter #12
Thanks for all your help. I keep telling the guy I live with what you have been saying and he just keeps arguing with me. He even claims to have found a code reader for it. The code reader is an OBD II reader which of course will not work. SO this should be interesting............................
 

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Thanks for all your help. I keep telling the guy I live with what you have been saying and he just keeps arguing with me. He even claims to have found a code reader for it. The code reader is an OBD II reader which of course will not work. SO this should be interesting............................
:D Where does he plan on using that reader?
 

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Tell him to go ahead and read the codes and let you know what's wrong with it. It'll be quite funny to see him looking for a port to plug it in......when there is none :) Get it on video!!!

Priceless :)
 

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Tell him to go ahead and read the codes and let you know what's wrong with it. It'll be quite funny to see him looking for a port to plug it in......when there is none :) Get it on video!!!

Priceless :)
:rofl: Video would be priceless.
 

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Discussion Starter #17
Tell him to go ahead and read the codes and let you know what's wrong with it. It'll be quite funny to see him looking for a port to plug it in......when there is none :) Get it on video!!!

Priceless :)
I should put it on youtube. To tell you how smart this guy is when I told him that I had gone just under 100 miles on an entire tank of gas he said and I quote "That's like 20 miles per gallon" as you smart people all know I have roughly a 20 gallon tank not a 5 gallon. I pointed that out to him. His reponse was in a very sarcastic tone as if I was the dumbass was "uh okay":D
 

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There is a spot in the right inner fender to plug in a live data scanner, but the tool would cost way more than the repair...fortunately though, a reman RENIX computer from napa or advance auto parts is only about $100.
 

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It sounds to me like the injector drivers in the ECU are junk. Unfortunately, I just threw away my old spare, or I would gladly have given it to you.
 

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Discussion Starter #20
You will never believe what simple fix seems to have made a huge improvement. It was suggested to me by someone to unhook the battery for a few min to reset the computer. Tried it. Big difference already.
 
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