Renix to H.O. wiring

Just bought a '91 4 door with the H.O. motor that I am swaping into my '90 with (you guessed it) a Renix system. I know about adapting the TPS and the like, but I am curious if anyone has swapped the harness as well? Does the under hood harness match up to the chassis harness? I guess the real question is whether it's really worth it? I am in the process of building a stroker and the thought of available chips for the H.O. computer is nice.

Any help or insight is always apperciated,
Alan

the underhood wiring is totally different. I am in the process of swapping a 98 into an 89 > It is all finished up except for the fuel pump problem. For that check my post on the modified tech forum. But if i had a donor xj i would have definitely used the newer wiring harness. If you want to use the old harness send me a message i will give you the details.

A word of caution. If your state has emissions testing, it is normally illegal to put an older engine into a newer vehicle.

I think you misread that. He is putting the motor from the 91 into his 90. So he will be using a newer motor. But unfortunately yes, Cincinnati does have emissions testing. Thanks Georgia Jeep, he doesn't get on a computer very often but I'll pass the word on to him and have him shoot you an email. If anyone else has any comments, suggestions, etc, please keep them coming. His current motor SUCKS and he needs to get this swap done as soon and as easily as possible. Thanks.

I just swapped 91 stuff into an 88. I would recommend pulling the entire vehicle wiring harness, including the rear harness. It will really make your life easier.

FWIW, I've heard the older Renix motors are better builders for a stroker.

Rick

I disagree with the above. Why scrap a perfectly good wiring harness. Keep the Renix wiring, swap the engine, and start driving. Once you start trying to swap the wiring you pretty much have to rewire the entire vehicle. Everything is different, so there is no neat point of interface where you can just mate everything up. Even the polarity on the gauges is reversed.

Eagle said:

I disagree with the above. Why scrap a perfectly good wiring harness. Keep the Renix wiring, swap the engine, and start driving. Once you start trying to swap the wiring you pretty much have to rewire the entire vehicle. Everything is different, so there is no neat point of interface where you can just mate everything up. Even the polarity on the gauges is reversed.

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BTW -- I don't recommend playing with aftermarket chips when you do a stroker. The chips advance the timing too far and require the use of 93 octane go juice. The strokers run better w/o chips, and many folks prefer to run Renix based strokers because they have the knock sensor to optimize timing.

Eagle said:

Everything is different, so there is no neat point of interface where you can just mate everything up. Even the polarity on the gauges is reversed.

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Exactly! Many connectors, the fuse block, guages, and other stuff is different between the 91 & 88. I didn't want to mess with tracing wires to figure out whats what. Point...the rear harness (which includes the fuel pump and rear lighting) is totally different from the 91 to 88. I didn't save that harness originally from the 91, but went to the junkyard and pulled one later, because I didn't want to have to trace and hook up one wire at a time. I'd rather just plug in a harness and go.

I don't think the underhood harness from the 91 motor will just plug in to the 90 harness inside the vehicle, as the fuse block is different.

The hardest harness to deal with is the underdash harness, for sure (there really is only 3 harnesses altogether...underhood, underdash, and rear)

I would take everything you can from the donor 91.

My .02

Rick

Rick XTRM XJ said:

I would take everything you can from the donor 91.

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Different strokes for different folks, I guess.

I would take nothing from the '91 except the engine. I'd skip the electrics and keep the '90 pure Renix.

I have a 89 XJ with a crack in the block. I was able to find 88 4.0 with about 130K for $130. I plan to drop in, but first I'm going to put all new gaskets and seals in the engine along with freeze plugs, oil pump, water pump, etc. I'll probably have the head redone while its off as well. This is going to be a toy, so no big hurry to put it back together here.

The guy I bought the engine from is also selling the matching automatic trans out of the 88 XJ 4WD cheap. Should I grab it and related parts and replace the BA 10/5 that's in my XJ? What auto trans was in this model year?

If I do swap, what else besides the obvious would I have to change? The ECU would have to change right? I definitely want to stay Renix. Not interested in the additional power, just want a toy for the beach and hunting.

If any of you guys are selling your Renix equipment, please let me know?

Thanks,
Tom

Eagle said:

Different strokes for different folks, I guess.

I would take nothing from the '91 except the engine. I'd skip the electrics and keep the '90 pure Renix.

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Agreed.

Although I can think of no redeeming qualities of the Renix system.

Rick

Hey guys,

Thanks for the input. I kind of figured I would get differing opinions about the computers. I didn't know if it was going to be an easy swap and worth looking into but my motor is trashed and I don't have the time to rewire anyway.

By the way, any one come across 5.0 motor mounts for the XJ?

Thanks,
Alan

Rick XTRM XJ said:

Agreed.

Although I can think of no redeeming qualities of the Renix system.

Rick

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And what good is the newer system? It's more complicated and sensor picky - why would you want that? If I had a choice of the Renix system or the OBDII in my '96 I would take the Renix any day. Renix has a knock sensor too...

ratherbcamping said:

The guy I bought the engine from is also selling the matching automatic trans out of the 88 XJ 4WD cheap. Should I grab it and related parts and replace the BA 10/5 that's in my XJ? What auto trans was in this model year?

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The -88 has an AW4. "Should" you grab it? Dunno. I like the 5-speed, although I am starting to agree that the auto is better for rock crawling. As a toy for the beach and hunting I see no need for the auto, but if it's cheap it might be good to have on hand for if the BA10/5 goes bad.

If I do swap, what else besides the obvious would I have to change? The ECU would have to change right?

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The TPS for the auto is different -- has output for the TCU. You'll need that. The tranny has a separate, free-standing TCU and you'll need that. The ECU for the auto is different. I know of people who are running 5-speeds with auto ECUs, but I don't know if it goes the other way. To be safe, grab the ECU. Also, the tranny mount is different for the auto.