Bought my 90 Renix a month ago. I knew that it wouldn't have a lot of power but the way it drives seems kinda absurd...
Can't seem too get it above 2300 rpm before it up shifts and rpm's drop too around 1800 rpm. Makes no difference if it's in D or I drop it too 3rd...
Going up a mountain hill is ridiculous. Shift down too 3rd and I can only get up to 35mph at 1800 rpm. Rig had rear axel replaced with a Ford 8.8. Is there some gear ratios that could be replaced too fix this?
Rig spent its life being towed behind an RV and I will do the same. Guess it gets good mileage 😜 but I'd prefer being able to climb a hill faster than a Yugo...

 

Have to give us more info. What gear ratio and tires are you running, have you tuned up the motor in a while, are you using O/D? Renix era XJs have only slightly less HP than the HO.

 

Running 31in tires. Rig runs fine. Not sure on the O/D. Is there a switch and what would it do ? Runs fine, idles fine. Plugs, wires, and cap were replaced a year ago. I know hp is low on these rigs, but when it runs like it can't get out of its own shadows way, makes me wonder what the hell 😜

 

Hi UncleBilly,
Several possibilities for your lack of power. My first thoughts would be a weak fuel pump or a plugged exhaust.
Lots of good info and diagnostics in Cruiser54's tips here:
https://www.cherokeeforum.com/f51/cr...x-tips-153657/

 

They are NOT low on power.

As for shifting, there are 2 things. The Power/Comfort switch. Is it in Power mode and does it light up when put in that mode?

You could have a clogged catalytic converter.

Click on the link below and do Tips 1,3,4,5, and 10 before doing anything else.

 

Thanks Cruiser. The Power/Comfort light switch does work, but it's normally left on comfort. I'll do your fixes with a buddy and see what works. Glad to hear that what's going on isn't normal...

 

See this:

Bypassing the Power/Comfort Switch on a Renix Jeep

Remove and unplug the switch. In the harness are 3 wires One has a stripe, one is tan, and the other black. Make a 4" jumper wire with a male spade at each end. Plug one end in the cavity for the tan wire and the other in the cavity for the striped wire and you'll be in permanent Power mode. Stuff the harness back in and reinstall the switch for looks.

If you happen to have a 91 or 92 XJ/MJ and it has the Power/Comfort switch, just jumper the Tan and Blue wires in the harness plug.

NEVER include the black wire when jumpering!!!

 

Can't he just flip the switch to power and leave it?

 

Possibly. The switches are very prone to failure and blowing the fuse.

 

The switch has worked in the past and the light goes on. Didn't notice any real difference. Then again I'm not sure how it's suppose too feel different anyway. Tried it again today on mountain roads and it felt the same as before. Once I get back too my RV where my tools are I'll try those fixes and see what happens...

 

Those switches are crappy. The light could be coming on but it's not doing it's job sending power to the tCU.

 

Wanted too let you guys know what fixed the problem for me. The throttle cable was frayed and that was part of the reason why I had no power. At first it would shift correctly if you did it manually. But in "D" no power. Shop thought it was some gizmo in transmission, but it wasn't. They had too replace the sensor for the throttle, or shifting. I forget, but it works now. Lots more power! Hope I can get up the hills to local Mountains better than 35mph now! 😜 Thanks for the help and hints...

 

Glad to hear you solved your problem. I knew something had to be wrong and that it wasn't inherent in the vehicle itself. I bought a 1990 Cherokee new at the end of 1989. I only had it for a few days when we took it to Stowe, Vermont to go skiing. It had lots of power in the "mountains" ... but then again it replaced my Pontiac 6000 so I was excited! ha ha