Drahcir495 Posted May 26, 2023 Share Posted May 26, 2023 I should have already done a search but I need some input on switching to the HO computer etc away from the Renix system. I have the Jeep at a Jeeps only mechanics shop. I have an 1998 XJ motor in my MJ now. I have the renix system running it. He suggested that I switch it over to the newer engine management system - computer and all that goes with it. Has anyone done this before? He makes it sound likes its no big deal to convert. I am not sure about this? It was running fine with the way its set up now. The guy really knows his stuff but what happens if something goes wrong and I have to explain the Frankenstein set up to someone else? I have a lot of questions but I just want to get the advice rolling. Link to comment Share on other sites More sharing options...
ratrapp Posted May 27, 2023 Share Posted May 27, 2023 If its running fine i would leave it alone.If its not broke then don't fix it. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 27, 2023 Share Posted May 27, 2023 You’d have to get the HO cluster, sending unit and speed sensor. It’s straight forward when you have he donor Jeep. Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 I thought the same thing if it ain't broke . . . he is saying the Renix computers are becoming harder to find when they fail and they are over 30 years old now. Also I should be utilizing the benefits of the newer motor and technology. He has a donor jeep there that he can scavenge from. And I just bought the REM from Nick last night before I got his call this morning ugh. I am way past wanting to do this myself. There was a time before starting a family that I would have taken this head on myself. Now, I just want it reliable and simple. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 27, 2023 Share Posted May 27, 2023 I’d hold out on the conversion. It sounds like an upsale and to get more money from you. Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 57 minutes ago, eaglescout526 said: I’d hold out on the conversion. It sounds like an upsale and to get more money from you. I think I agree Link to comment Share on other sites More sharing options...
neohic Posted May 27, 2023 Share Posted May 27, 2023 1 hour ago, eaglescout526 said: You’d have to get the HO cluster, sending unit and speed sensor. It’s straight forward when you have he donor Jeep. Flywheel/flex plate too. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 27, 2023 Share Posted May 27, 2023 22 minutes ago, neohic said: Flywheel/flex plate too. Forgot about those. Wiring too. Link to comment Share on other sites More sharing options...
Pete M Posted May 27, 2023 Share Posted May 27, 2023 "harder to find" does not equal "impossible to find". plenty of guys out there parting out the old Jeeps if you ever need one. Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 59 minutes ago, neohic said: Flywheel/flex plate too. Yep, I had to keep a lot to get the new motor to work in the jeep Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 20 minutes ago, Pete M said: "harder to find" does not equal "impossible to find". plenty of guys out there parting out the old Jeeps if you ever need one. Good point! I have another Renix computer in my spare parts bin that I have no idea where it got it?? I will be grabbing them out of the junk yards when I find them. I'm so glad that I come here for advice . . . backing slowly from the edge Link to comment Share on other sites More sharing options...
cruiser54 Posted May 27, 2023 Share Posted May 27, 2023 Excellent responses^^. I agree. Hey guys, it's not really an issue, but you should be snagging ECUs from Renix Jeeps in the junkyard. Get an 89 or 90 ECU for your personal Jeep and save your old one as a backup would be great. But having a spare of any Renix ECU would be nice. Start snagging TCUs also!! 88 to 90 are best. 87 had a clunky shifting program. Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 Thanks for the advice Cruiser Really went down a rabbit hole with the YouTube video's Link to comment Share on other sites More sharing options...
cruiser54 Posted May 27, 2023 Share Posted May 27, 2023 Here's a few other things. We don't need OBD 1 or 2. We have the REM now. And before that had simpler ways to diagnose stuff. And, there's this: HO myth buster Renix in 90 made 182 HP. HO in 91 made 190 HP. That's 8 HP difference. HO only made more HP than Renix at higher RPMs and not a bit more torque. HO had a 58 mm throttle body versus a 52 mm throttle body on a Renix. That’s 20% more air available through the HO throttle body. The HO also had a better design header. See where I'm going with this? It’s only a 4% horsepower increase….. The whole 8HP was not mostly from the head, but from the bigger TB and better exhaust manifold. Put a 60mm TB from www.strokedjeep.com on your present manifold using the Renix head, eliminate the "crush" in your headpipe with proper re-routing, and go for it. HO stands for Highly Overrated. __________________ And always remember this: The HO was just an effort by Chrysler's engineers to piss on AMC's fire hydrant claiming it as theirs. The same engineers who said the 4.0 would be dropped soon after the 1987 buyout and that the 4 cylinder was doomed also. Hell, they ended up using the 4 cylinder in their beloved POS Dakota!! The 4.0 lasted at least 18 more years!! Keep in mind I lived through this stuff. I worked at a Jeep dealership from 1980 through 1992. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 27, 2023 Share Posted May 27, 2023 38 minutes ago, cruiser54 said: Hell, they ended up using the 4 cylinder in their beloved POS Dakota!! I snicker at that every time. Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 Definitely puts all things in perspective. I think I have the HO head, intake and throttle body on it from the swap IIRC? Don't remember all the details since its been at least 10 years since I did it. You are a wealth of knowledge for sure - thank you. You saved me close to 2k. Link to comment Share on other sites More sharing options...
cruiser54 Posted May 27, 2023 Share Posted May 27, 2023 How many bolts hold the throttle body on? Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 27, 2023 Author Share Posted May 27, 2023 I'm in Wisconsin right now so I will have to check that when I get home.I do know it has a cold air intake and throttle body spacer if that can tell you anything? Link to comment Share on other sites More sharing options...
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