Zenroth

I just recently picked up an 89 Wagoneer 4.0 auto, and have run into a few problems I would love help or advice with.

1. Popping/klunking type of sound from the front end when turning at slow speeds. I looked over the various components today and noticed one thing that stood out to me. The tie rod/central steering link, I'm able to rotate back and forwards a bit by hand with enough force, and essentially cause a pop as the ends turn over a bit where they connect to the wheel/steering knuckles. I have little experience on the suspension/steering side of mechanics so I'm not sure if this is normal or not, but I suspect not.

2. Vibration problems at around 55mph+ seems like there is a huge list of things that could cause this unfortunately. The u-joints seem decent, and actually 2 or 3 of the drive shaft ones look to have been replaced as they have grease fittings on them. Would the tie rod problem above be causing vibrations? Everything else seemed pretty tight down there, and without play. I was going to try an tighten down the trackbar more, but it actually seems like its rather difficult to access the bolts/nuts to it.

3. Seemingly slow acceleration when going past 45mph. Its like the jeep will throw you back in your seat on the low end, but it seems to take a long time to gain speed after around 45mph. I don't remember if this is just a cherokee thing or not, and I've been driving sports cars for the last 6 years so.. this problem escalates when trying to go up a decently steeped hill, hard to gain speed, hard to keep speed.

I've replaced plugs, plug wires, cap, rotor, crankshaft sensor, and fuel filter to resolve earlier problems. Fuel pressure seems to be good at 39psi, though the fuel pump does start to whine loudly if the car is driven for a hour or so straight. (Seems like this is semi-common? Not sure if the pump could be part of my acceleration problem, given it does seem to have good pressure atleast at engine idle.)

Perhaps the TPS? I haven't looked at it any, seems like its quite a bit more evolved to adjust than what I'm use to from pontiac/chevy.

Thanks!

cruiser54

1. Be sure to tighten the bolts that hold the track bar bracket to the driver's side frame rail even though they may appear tight.

3. Good job on the tune-up parts. The Power/Comfort switch on the dash. Make sure it's in the Power mode and the switch lights up. Adjust the TV cable per the following link:
https://www.cherokeeforum.com/f2/free-quick-fix-41821/

I woild do a complete ground refreshing on your Renix Jeep along with some other things just to eliminate future issues. This is very important.
Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, and wasted money replacing unnecessary components.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18" long with a 3/8" lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.
A further improvement to the grounding system can be made using a #4 cable, about 10" long with 3/8" terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.
　
　
If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.
　
Revised 11-28-2011

Zenroth

Thanks cruiser. I did the TV cable adjust and switched to "Power" mode and it does seem quite a bit better though I need to test it more at highway speeds.

Is using the "Power" mode okay for fulltime use? I had read or heard somewhere it was really only meant for towing operation.

I also went ahead and followed up with cleaning up the nasty grease and oil coated grounds, and running some additional ground cables.

Vibration remains the biggest issue at current, maybe the tires or toe adjustment is out of spec. I did managed to tighten the trackbar bracket bolts a tad bit more with the old breaker bar and cheater pipe, but they we're really tight to start with.

XJ.89.Limited

-Torque the tracbar bolts to the right specs, I did that and My death wobble got a little better and I had no more pop in the steering. My pop was actually coming from the passenger side end, so torque that right too. I noticed that rotating my tires also helped with my death wobble pretty noticeably. The tires I had on the front had lost most of the balancing weights, so they rolled pretty sloppy.

-As for the acceleration, deal with it. haha. The old renix engines don't produce much horsepower, so they honestly suck at highway speeds. Low end torque is pretty good though. I've heard of guys launching against mustangs and completely beating them to the next stop light, especially with the newer HO 4.0.

-TPS adjustment is a good idea, that can throw a lot of things off.

-ALWAYS keep the switch on power. You honestly get a little better mpg, it shifts a hell of a lot better, and it doesn't bog down as much on hills. They did away with it after '90 (I think, don't quote me on the exact year) and just hard wired it to always perform like that.

-As far as the fuel pump, I've heard plenty of stories on that. Not too sure if it's bad or not. Mine constantly makes a hissing sound and it runs just fine.

-Doing what cruiser says is also highly recommended though. He's the resident renix guru if you haven't noticed yet. He has a ton of different write-ups for renix fixes. If you don't know what a renix is, it refers to the joining of Renault and Bendix for the fuel injection system. A renix has it's own little quirks compared to the newer cherokees, just a heads up. Not a bad thing really, just something to keep in mind. I actually like having my renix. I learn about it instead of having some guy plug a fancy code reader up to it and telling me how much it'll be to fix. With a renix, you actually have to diagnose things the old school way.

cruiser54

Good job. Power is the mode you wanna use. The factory eliminated that switch in 91 or 92 and defaulted the TCU to Power mode. Comfort mode = Grandma mode.

Switch lights up and 7.5 amp "trans" fuse in fuse box is okay?

cruiser54

I agree with everything you stated except that Renix doesn't produce much horsepower. They ended up only 8 HP shy of the HO with the same torque. Add a 60mm throttle body to a Renix and eliminate the "crush" in the downpipe and see what happens!!

XJ.89.Limited

Haha, it's on my list of things to do. I priced out throttle bodies a few times and they're just a little out of my league at the moment. The cheapest I found was $160 Eventually I wanna do a full exhaust and do away with the stupid "crush". I was thinkin a nice set of headers, 2.5 inch mandrel bent pipe all the way through, and a high flow cat. I'll probably keep my muffler or go to a flowmaster.

cruiser54

www.strokedjeep.com. $90 exchange and they come with a bigger butterfly , too. Go for it.

Zenroth

Yep switch lights up, all the fuses are good. Power mode has actually helped quite a lot. Though I'm hesitant to push it to much due to the bad vibration that happens at around 50+ currently.

Today I redid the front brakes and rotors due to having some nasty brake vibration/shake and pedal push back (I ended up completely rebuilding the drum brakes the day after I bought it due to needing to bleed the brakes and the bleeder valve stripping out the wheel cylinder.) and that seems to have helped the overall vibration quite a bit as well. Still something is amiss, maybe it really just alignment or tire balance. Would be nice.

cruiser54

Check the tightness of the track bar to driver's side frame rail bolts. Even though they appear tight, put the old breaker bar to them to be sure.

What are the tires like? Rotated them to see if the vibe changes?

XJ.89.Limited

We'll see when I get a few more paychecks. Money is pretty tight right now.

67 GMC

I'd try rotating the tires to see if the vibration changes. At 55MPH the balancing does matter more than when driving around the block.

Zenroth

Yeah I may just take it to a tire place and let them throw them on a balancer and also rotate the tires. Every time i go to take a tire off this thing, a lug nut cap seems to break, and I'm left fighting usually bent lug nuts with the 18mm socket and breaker bar.

cruiser54

I just bought a set of solid chrome lugnuts for my Comanche for $30 from Discount last time I had them do the rotate and balance. At some point, the 18mm isn't gonna work on those old lug nuts. They're soft and round off easily.

67 GMC

Changing the lug studs shouldn't bee too hard. I haven't done them on a Cherokee but on other vehicles I've had, you take the rotor and caliper off, and pop them out with a drift and hammer. Then buy new ones and put them on and using a spacer, just tighten till snug.

There's some U-tube videos on this. No point putting up with bent lug nuts as they'll break at a shop or when you don't want them to.