1995 HO install in 1987 XJ

I have an 87 XJ with 260k on it. I have a low miles 95 HO engine. I have read where I can use my old sensors and computer with the HO engine to make it work. Can I get a 95 computer and wiring harness and make it work that way? My 87 has a tps harness for the auto transmission. If I use the 95 harness and computer, how will this affect the transmission? Thanks for sharing your knowlege.

if you switch to the '95 wiring, you need the ENTIRE vehicle harness, every single thing that is connected to it and you'll also need just about everything under the hood.

if you had an entire 95 XJ sittin around for a parts donor, then I'd say go for it, but it will be MUCH easier to swap all sensors, distributor and flexplate and then adapt the Renix TPS to the HO throttle body.

The Renix FI really is a superior setup IMHO, and it is more adaptable to any modification aside from forced induction/NOS.

CheapXJ said:

if you switch to the '95 wiring, you need the ENTIRE vehicle harness, every single thing that is connected to it and you'll also need just about everything under the hood.

Click to expand...

I disagree, unless the '95 wiring is radically different from '93 (ZJ). I put a 93 ZJ 4,0 under the hood of my 86 XJ, and the wiring is really quite logically split between engine/transmission and the rest of the car (lights, interior equipment and so on), so we just cut all cables between the power distribution center and the second fuse box. It wasn't as bad a job as it may sound, but you'll of course need complete (and hopefully remotely accurate, i.e. preferably not Haynes) wiring diagrams for both vehicles.

But, I would recommend using HO computer, sensors and wiring.. I feel this is a more modern and accurate system, but I don't know of course. If it's just a trail rig, do what's easiest, but if you care about mileage and/or horsepower, use the HO computer/sensors/wiring. (Just my personal opinion, NOT fact)

diagnosing problems on a vehicle with a cut+spliced wiring harness is a pain in the ass.

yes, it works, but working with stuff like that sucks.

I'm sure you also took the ZJ tranny when you did the swap. (XJ tranny wiring is RADICALLY different than the ZJ wiring) either way, you had no choice but to mess with wiring.

just because it's newer (HO computer) doesn't mean it's better.

CheapXJ said:

diagnosing problems on a vehicle with a cut+spliced wiring harness is a pain in the ass.

yes, it works, but working with stuff like that sucks.

I'm sure you also took the ZJ tranny when you did the swap. (XJ tranny wiring is RADICALLY different than the ZJ wiring) either way, you had no choice but to mess with wiring.

just because it's newer (HO computer) doesn't mean it's better.

Click to expand...

Nope, 1993 ZJ, AW4. Excactly the same as XJ (well, maybe some wire colors are different, that I haven't checked). Diagnosis is no worse, I just need two books. But then again, I did the splicing and know what's which, would be worse if someone else did it or if I sell it.

Maybe you're right about the HO computer, I don't know, I just consider the fact that the HO has quite a few more HP and consumes a bit less, but that of course does not lie in the injection system alone.

I have a 1995 4.0 in my 88.

I swapped in the WHOLE powertrain, tranny and tcase included, as well as the complete harness.

I had to do some splicing so the GM saginaw column would work, and get the signal lights working properly.

I also swapped in my 95 cluster gauge, since the 88 is a cable-driving set-up....

did the whole thing in a day.

Beezil said:

did the whole thing in a day.

Click to expand...

:shocked:

Took me half a year, respect!

Amund2 said:

:shocked:

Took me half a year, respect!

Click to expand...

easy when you have a forklift!

Geez Beez...Thanks for reminding me of the task ahead later this year....Not having access to a "hangar" with a forklift I'll probably do it ghetto style in my driveway...

BTW... Renix easier to fiddle and modify...my 2 cents
Modified HO throttle body to Renix TPS in about 2 hours with many smoke and beer breaks...

Gil "Stroker needs an Eaton M90" Bullycatz

Amund2 said:

I just consider the fact that the HO has quite a few more HP and consumes a bit less, but that of course does not lie in the injection system alone.

Click to expand...

The newest HO engines (for the XJ) produce only 13 more horsepower than the Renix, and don't produce any more torque. The added horsepower is at the top end of the RPM range, where nobody operates the engine anyway.

I own both an '88 and a 2000, both 5-speeds. The '88 (Renix) delivers better fuel economy with 240,000 miles on it than the 2000 with less than 20,000 miles.

Additionally, the Renix has a knock sensor and the HO does not.

I see no overriding need to try to "upgrade" a Renix-based XJ to the Chrysler ECU and wiring. I don't see it as an improvment, only a change. Just change the sensors and swap in the engine. If you want to retain the HO throttle body, there have been write-ups on how to adapt that to work with the Renix system.

Eagle said:

I don't see it as an improvment, only a change.

Click to expand...

Oh eagle seagull, haven't you been paying attention?

change is GOOD.

I finished my 1998 HO swap into my 1990 2dr. I had a complete donar vehicle so I took EVERYTHING to make it work, including the 98 fuel tank with pump and lines. The less to splice the better in my book. All I really had to do was splice a couple wires from the old harness from the ignition switch to control power goin to the 98 fues/relay block to switch the fuel pump, ASD, Ignition relays propperly. Fired right up on the first try. As for the rest of the truck, I havnt decided if I'm gonna swap dashes for the guages etc... I'll see how it runs first.

I did it over time after work etc.. but that actuall amount of time I spent wasn't more that a few days worth. More time stripping the donar 98 than working on the 90.

http://www.jdsoffroad.com/chrisg/images/XJ/Gallery/index.htm

I havnt taken any more recent ones.

PS> If anyone needs anything off a 1998, let me know. I have lots of parts left over.

Renix rules, of that there is no doubt.

My dream renix would use the Gen 3 block, the Gen 3 intake manifold and TB, and everything else Renix.

The mapping on a Renix computer is so wide that it would very likely run on anything from goat piss to Jet A.

One downside to Renix: the miles and miles of underhood wiring really sucks.

OMG. I think I just agreed with Eagle.

CRASH

CRASH said:

Renix rules, of that there is no doubt.

My dream renix would use the Gen 3 block, the Gen 3 intake manifold and TB, and everything else Renix.

The mapping on a Renix computer is so wide that it would very likely run on anything from goat piss to Jet A.

One downside to Renix: the miles and miles of underhood wiring really sucks.

OMG. I think I just agreed with Eagle.

CRASH

Click to expand...

With the recent increase in gas prices I was wondering. How much for a gallon of goat piss? Is this a URF approved and sanctioned fuel? :wave:

Bryan