messy Posted November 29, 2015 Share Posted November 29, 2015 I have a 89 comanche 2wd standard 4.0, would the ecu be compatible in a 90 comanche 4wd auto 4.0? Link to comment Share on other sites More sharing options...
Strokermjcomanche Posted November 29, 2015 Share Posted November 29, 2015 Is the 90 auto or std ? Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 29, 2015 Share Posted November 29, 2015 According to the parts manual, yes if the transmissions match (manual or auto). 89-90 4.0's used the same ECUs. 53005429, XJ, MJ, 6 Cyl. Engine, w/Man. Trans., 1989-9053005428, XJ, MJ, 6 Cyl. Engine, w/Auto. Trans., 1989-90 Link to comment Share on other sites More sharing options...
messy Posted November 29, 2015 Author Share Posted November 29, 2015 Thanks for the replies, it is an auto i edited it. Link to comment Share on other sites More sharing options...
Pete M Posted November 29, 2015 Share Posted November 29, 2015 ECUs aren't really known for being a common failure point. what symptoms are you experiencing? Link to comment Share on other sites More sharing options...
cruiser54 Posted November 30, 2015 Share Posted November 30, 2015 The only difference I believe between the manual and auto ECUs is some kind of idle stability differences when in gear on the autos. . Link to comment Share on other sites More sharing options...
messy Posted November 30, 2015 Author Share Posted November 30, 2015 " ECUs aren't really known for being a common failure point. what symptoms are you experiencing? where do i start? I found a 90 comanche that has been sitting for who knows how many years, been fixing small things here and there and got it running pretty well. So i decide to go on a test drive through a trail behind my house and the jeep started stuttering, quit moving then died. Started working and found i have no spark so i start reading and testing things, long story short i put in a used cps and it ran :-). Drove back to the garage and shut it down, came out later and it won't start. NO SPARK! lol So i have 3 comanche's and the 89 is a parts truck, received a brand new cps this morning and going to try that but was curious if the puter outa the 89 would work. I have redone all the grounds in the engine compartment, did ohms tests on coil, undid all electrical connections and added di-electric grease. so i am hoping when i put in the new cps, hope it works. Link to comment Share on other sites More sharing options...
messy Posted November 30, 2015 Author Share Posted November 30, 2015 Well i got the NEW cps installed, turned it over and nothing :-(. Stuck. Kinda funny, it will start if i unplug the cps and wait 5-10 min, plug back in it will run for 1-5 secs then abrubtly dies and will not restart. so i unplug 5-10 min plug back in and it starts WTH. Link to comment Share on other sites More sharing options...
messy Posted December 2, 2015 Author Share Posted December 2, 2015 *FIXED* well seems I didn't clean 2 connections, after a friend pointed them out as a possible problem. It was the 2 connections to the left of the head "i think one grey and one black", one of them was pretty corroded up, cleaned greased and running. Thankx Link to comment Share on other sites More sharing options...
cruiser54 Posted December 2, 2015 Share Posted December 2, 2015 The ones in Tip 10? Link to comment Share on other sites More sharing options...
messy Posted December 2, 2015 Author Share Posted December 2, 2015 The ones in Tip 10? That would be them, my dumb @$$. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 2, 2015 Share Posted December 2, 2015 The ones in Tip 10? That would be them, my dumb @$$. Whoops..... Hopefully others see this and see the importance of completing the first few Tips right off the get-go. Link to comment Share on other sites More sharing options...
messy Posted December 3, 2015 Author Share Posted December 3, 2015 Well just as an update, seems when the truck starts to get warm it is still stalling out with no spark. I have checked power at the coil after it stalls out and continue reading voltage, so I have a new coil I am getting ready to install. In the lovely snow I might add. :-/ Link to comment Share on other sites More sharing options...
messy Posted December 3, 2015 Author Share Posted December 3, 2015 I think that was the final issue with spark, seems to have fixed a tiny miss i had also. Thankx again for the help and links to tech. issues. Link to comment Share on other sites More sharing options...
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