Idea for pulling codes on a renix
Thread Starter
Newbie
Joined: Jan 2022
Posts: 14
Likes: 0
From: Calgary, Alberta
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0
Hey all, forgive me if this has already been discussed or if I have it all wrong in my head.
If I understand correctly, I can swap my 1988 ECU for something like a 1995 ECU, right?
And if I do that, could I then pull codes instead of throwing parts at mystery problems?
It would be nice if she could tell me what she needs, rather than expecting me to read her mind, know-what-I-mean?
I've been doing electrical work and parts work every weekend, and I still have weird ticks and a high idle, especially in park and neutral. Difficulty accelerating past 70km/h.
Thoughts?
If I understand correctly, I can swap my 1988 ECU for something like a 1995 ECU, right?
And if I do that, could I then pull codes instead of throwing parts at mystery problems?
It would be nice if she could tell me what she needs, rather than expecting me to read her mind, know-what-I-mean?
I've been doing electrical work and parts work every weekend, and I still have weird ticks and a high idle, especially in park and neutral. Difficulty accelerating past 70km/h.
Thoughts?
CF Veteran


Joined: Mar 2015
Posts: 1,203
Likes: 155
From: Northern CT
Year: 1995
Model: Cherokee
Engine: Turbo 4.0
The 91-95 ecu SBEC2 won't run on the 88 harness. The crank trig is also different. The SBEC2 can provide live data but will need a reader that can handle obd1 chrysler specific data communication.
nickintimedesign.com makes a renix live data reader. Very cool guy to talk with.
Cruiser should be here shortly.
nickintimedesign.com makes a renix live data reader. Very cool guy to talk with.
Cruiser should be here shortly.
Thread Starter
Newbie
Joined: Jan 2022
Posts: 14
Likes: 0
From: Calgary, Alberta
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0
The 91-95 ecu SBEC2 won't run on the 88 harness. The crank trig is also different. The SBEC2 can provide live data but will need a reader that can handle obd1 chrysler specific data communication.
nickintimedesign.com makes a renix live data reader. Very cool guy to talk with.
Cruiser should be here shortly.
nickintimedesign.com makes a renix live data reader. Very cool guy to talk with.
Cruiser should be here shortly.
CF Veteran



Joined: Aug 2020
Posts: 2,138
Likes: 580
From: SoCal
Year: 1988
Model: Cherokee (XJ)
Engine: 4.0L
You can test all the sensors with a multimeter. Granted, Nickintime reads live data and that's very useful in diagnosing issues. Doesn't matter though if you can't get one. Snap-on has the MT2500 scanner that works if you have the jeep cable and cartridges.
On my '88, I've found that I can not adjust my TPS to the spec. I get a very high idle. I have to tweak mine a bit to get the idle correct. I don't recall the output voltage. I did pass CA smog test recently by a wide margin so it's running well at 208K.
Anyway, check out Cruiser54's (he's a mod here) site at Cruiser54.com. When he gets here, he'll say to do tips 1-5 first. Tip 8 is the TPS adjustment, tip 11 is the IAC and TB cleaning. There are other tips too you should work through at some point.
On my '88, I've found that I can not adjust my TPS to the spec. I get a very high idle. I have to tweak mine a bit to get the idle correct. I don't recall the output voltage. I did pass CA smog test recently by a wide margin so it's running well at 208K.
Anyway, check out Cruiser54's (he's a mod here) site at Cruiser54.com. When he gets here, he'll say to do tips 1-5 first. Tip 8 is the TPS adjustment, tip 11 is the IAC and TB cleaning. There are other tips too you should work through at some point.
Thread Starter
Newbie
Joined: Jan 2022
Posts: 14
Likes: 0
From: Calgary, Alberta
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0
You can test all the sensors with a multimeter. Granted, Nickintime reads live data and that's very useful in diagnosing issues. Doesn't matter though if you can't get one. Snap-on has the MT2500 scanner that works if you have the jeep cable and cartridges.
On my '88, I've found that I can not adjust my TPS to the spec. I get a very high idle. I have to tweak mine a bit to get the idle correct. I don't recall the output voltage. I did pass CA smog test recently by a wide margin so it's running well at 208K.
Anyway, check out Cruiser54's (he's a mod here) site at Cruiser54.com. When he gets here, he'll say to do tips 1-5 first. Tip 8 is the TPS adjustment, tip 11 is the IAC and TB cleaning. There are other tips too you should work through at some point.
On my '88, I've found that I can not adjust my TPS to the spec. I get a very high idle. I have to tweak mine a bit to get the idle correct. I don't recall the output voltage. I did pass CA smog test recently by a wide margin so it's running well at 208K.
Anyway, check out Cruiser54's (he's a mod here) site at Cruiser54.com. When he gets here, he'll say to do tips 1-5 first. Tip 8 is the TPS adjustment, tip 11 is the IAC and TB cleaning. There are other tips too you should work through at some point.
CF Veteran



Joined: Aug 2020
Posts: 2,138
Likes: 580
From: SoCal
Year: 1988
Model: Cherokee (XJ)
Engine: 4.0L
Other than the FSM, the other link I have is this one.
https://www.lunghd.com/Tech_Articles...iagnostics.htm
As far as the rest, yes, "all of the above". If you still have the 2 part vacuum harness, check the junction at the manifold.
If you have a cracked exh manifold, also check the motor mounts and the trans mount. If you don't, you should check them anyway.
https://www.lunghd.com/Tech_Articles...iagnostics.htm
As far as the rest, yes, "all of the above". If you still have the 2 part vacuum harness, check the junction at the manifold.
If you have a cracked exh manifold, also check the motor mounts and the trans mount. If you don't, you should check them anyway.
CF Veteran


Joined: Dec 2017
Posts: 1,524
Likes: 412
From: San Mateo, CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0 Renix, stock.
Use the Snap On MT 2500 scan tool to read Renix data. You will need the correct Jeep Chrysler cartridge and plug Ebay got them in $200 to $300 range . These untis can scan many types of pre obd cars that have a factory type scan port.
These scan everthing the nick in time unit does, so if his is nlt available, the snap on scanner is a great option.
I bought a used one, very helpful for my 1990 renix. Helped me solve some vexing problems. shows all sorts of stuff, including manifold vacuum, temps, sensors, Oxygen etc...
High recommendation.
These scan everthing the nick in time unit does, so if his is nlt available, the snap on scanner is a great option.
I bought a used one, very helpful for my 1990 renix. Helped me solve some vexing problems. shows all sorts of stuff, including manifold vacuum, temps, sensors, Oxygen etc...
High recommendation.
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CF Veteran


Joined: Dec 2017
Posts: 1,524
Likes: 412
From: San Mateo, CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0 Renix, stock.
Use the Snap On MT 2500 scan tool to read Renix data. You will need the correct Jeep Chrysler cartridge and plug Ebay got them in $200 to $300 range . These untis can scan many types of pre obd cars that have a factory type scan port.
These scan everthing the nick in time unit does, so if his is nlt available, the snap on scanner is a great option.
I bought a used one, very helpful for my 1990 renix. Helped me solve some vexing problems. shows all sorts of stuff, including manifold vacuum, temps, sensors, Oxygen etc...
High recommendation.
These scan everthing the nick in time unit does, so if his is nlt available, the snap on scanner is a great option.
I bought a used one, very helpful for my 1990 renix. Helped me solve some vexing problems. shows all sorts of stuff, including manifold vacuum, temps, sensors, Oxygen etc...
High recommendation.
CF Veteran


Joined: Dec 2017
Posts: 1,524
Likes: 412
From: San Mateo, CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0 Renix, stock.
Evidently the Nick REM is not available now. It was backordered for me, hence I bought the snap on tool The snap on tool can also scan many many other makes and models of pre obd car that have diagnostic ports. It is a good choice, specially when the other is not available.
Thread Starter
Newbie
Joined: Jan 2022
Posts: 14
Likes: 0
From: Calgary, Alberta
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0
Does anyone have an REM they would be willing to sell to me? Or know someone who might? Nick's site guesses availability in 2023, but I can't wait that long.
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