Ecu and harness question

[Blackbetty00]

So I have a 88 mj that I bought a 4.6 stroker an ax15 and a 231 tcase the jeep was originally a 2.5 manual 2wd it’s 4x4 now but previous owner chopped the harness at firewall what is my best option wiring harness wise I have a full harness from a 99 same year as motor but is it comparable with the interior harness? And my second question is what are you guys doing for Ecus and can you buy a ecu and harness kit?

[cruiser54]

No wonder there are no responses!! Holy run-on sentences. Hurts my head to read. 

[thecodemonk]

On 6/14/2020 at 4:00 PM, Blackbetty00 said:

So I have a 88 mj that I bought a 4.6 stroker, an ax15, and a 231 tcase. The jeep was originally a 2.5 manual 2wd, it’s 4x4 now, but previous owner chopped the harness at firewall. What is my best option wiring harness wise? I have a full harness from a 99, same year as motor, but is it comparable with the interior harness? And my second question is what are you guys doing for Ecus? and can you buy a ecu and harness kit?

 

Fixed the punctuation.

 

Is the rest of the body setup as original? (closed loop cooling? renix stuff?).  

 

Pre-90 is the renix years, newer than that is the HO years (using a chrysler ecu, rather than a renix one).  I think a number of things changed on the body wiring at 97 and up as well (since the interior and exterior design changed a bit).  I would guess you're probably looking at some tracing and splicing wires either way.

 

Oh yeah...and for ECUs, most of us are running the stock ones.  I haven't heard of a ton of failures on them.  I know for some junkyards here, you can buy a whole setup of engine, harness and ECU on newer engines.  

 

If it were me in your situation, I'd probably work with the full harness from the 99 and use an ECU from the same year from a junkyard or something and just splice where necessary to get the body electronics working after the engine is running.

[1989commanche]

6 hours ago, cruiser54 said:

No wonder there are no responses!! Holy run-on sentences. Hurts my head to read. 

He used two question marks??

[cruiser54]

So, you have a 99 engine with all the bolt on injection parts already? Distributor, throttle body and manifolds etc? 

[Blackbetty00]

On 6/16/2020 at 7:49 AM, thecodemonk said:

 

Fixed the punctuation.

 

Is the rest of the body setup as original? (closed loop cooling? renix stuff?).  

 

Pre-90 is the renix years, newer than that is the HO years (using a chrysler ecu, rather than a renix one).  I think a number of things changed on the body wiring at 97 and up as well (since the interior and exterior design changed a bit).  I would guess you're probably looking at some tracing and splicing wires either way.

 

Oh yeah...and for ECUs, most of us are running the stock ones.  I haven't heard of a ton of failures on them.  I know for some junkyards here, you can buy a whole setup of engine, harness and ECU on newer engines.  

 

If it were me in your situation, I'd probably work with the full harness from the 99 and use an ECU from the same year from a junkyard or something and just splice where necessary to get the body electronics working after the engine is running.

Thank you, I will Probaly end up doing that. I’ll try and see if I can’t splice the new harness into the old one to keep the interior nice. 

[Blackbetty00]

On 6/16/2020 at 1:28 PM, cruiser54 said:

So, you have a 99 engine with all the bolt on injection parts already? Distributor, throttle body and manifolds etc? 

Yes, I have everything the motor needs to run. Making it run in the jeep is the issue due to wiring