Eagle

I was only able to vote once. Tried again, a couple of times, but the number of votes didn't change. Where do you guys see the scores for the competition?

Those wheels might be Wrangler Canyons, which would be 15x8, but they are more likely ZJ Canyons, which are 15x7. Nice wheels, though. The front clip will go right onto your 89, but you must use the entire header, grille and headlight bezels together with the header. Jeep changed it in 1990 -- the older grille and headlight doors won't work with the new header, and the new grille and headlight bezels won't work with the old header. There is no "cladding" on the front fenders. That's a rubber rub strip about 2-1/2" wide that's held on with double-stick tape, and matte black paint from the rub strip down. No problem moving the fenders over to the MJ.

"Other" "Other" wasn't an option. My bad. It was supposed to be, and I'll make sure it shows up on all three polls Gents, it is not necessary to respond in this thread or to explain your votes. I'm not trying to re-open the debate, I'm trying to collect raw data so we can try to get an objective assessment of the current state of understanding of death wobble. I can't stop you from responding, but in all honesty I think for the purpose it would be better if y'all would just vote, and NOT discuss.

I apologize if I created confusion there. Yeah, on the Renix vehicles the ECU reads the CPS. What messed me up is that back when my '88 XJ was a couple of years old I inquired at a dealership about adding cruise control, and the service manager (who lied to me about other things, so I don't know why this stuck) told me it couldn't be done because there was no way to connect a cruise control to the "vehicle speed sensor." I guess that's still stuck in a mental pigeon hole. And in a perverse way, it's true -- since there is no "vehicle speed sensor," there's no way to interface cruise control with it. Why the guy couldn't just tell me "It's a bunch of work and we don't want to be bothered." I don't know. He was just one of those people who found it easier to always lie. I was only at that dealership because the original dealership had been sold and the new owners were crooks. I quickly found that this other dealership wasn't a lot better and stopped going there, too.

Is that the case with the older speedos? Not sure how a cable driven speedo would produce such a signal. I'm still pretty new to the whole MJ thing. :doh: You're right, of course. My theory remains valid, the ECU is still being folled regarding actual road speed. But you are correct, it's the CPS that tells the older 4.0L what the speed is, not a direct speedo gear output.

"Other"

After yet another exchange on the topic of "What causes death wobble?", I thought it might be interesting to get some feedback as to exactly what our members think is/are the cause(s) of death wobble. I'm especially interested to see if there is any consensus, or if opinions are all over the map. Hence, a poll. I don't see a way to do a 3-tiered poll, so this is Part 3 of three different polls. Please vote for what you think is the third most important factor contributing to or causing death wobble. Two parallel polls will ask for your first and second choices -- please be sure to vote in all three. At the end, I'll score the results. Each first-place vote will be worth 3 points, each second-place vote will be worth two points, and each third-place vote will be worth one point. The poll will stay open for one week.

After yet another exchange on the topic of "What causes death wobble?", I thought it might be interesting to get some feedback as to exactly what our members think is/are the cause(s) of death wobble. I'm especially interested to see if there is any consensus, or if opinions are all over the map. Hence, a poll. I don't see a way to do a 3-tiered poll, so this is Part 2 of three different polls. Please vote for what you think is the second most important factor contributing to or causing death wobble. Two parallel polls will ask for your first and third choices -- please be sure to vote in all three. At the end, I'll score the results. Each first-place vote will be worth 3 points, each second-place vote will be worth two points, and each third-place vote will be worth one point. The poll will stay open for one week.

After yet another exchange on the topic of "What causes death wobble?", I thought it might be interesting to get some feedback as to exactly what our members think is/are the cause(s) of death wobble. I'm especially interested to see if there is any consensus, or if opinions are all over the map. Hence, a poll. I don't see a way to do a 3-tiered poll, so this is Part 1 of three different polls. Please vote for what you think is THE most important factor contributing to or causing death wobble. Two parallel polls will ask for your second and third choices -- please be sure to vote in all three. At the end, I'll score the results. Each first-place vote will be worth 3 points, each second-place vote will be worth two points, and each third-place vote will be worth one point. The poll will stay open for one week.

A friend's stroker did that when it was running lean. He played with an adjustable MAP sensor to richen it a bit, but in the end he went to larger injectors. I'm not saying you should go to larger injectors on a stock vehicle, but this could nonetheless be fuel related. First, it may just be old gas that doesn't have much "oomph" left in it. It could also be a partially plugged fuel filter. That's on the driver's side frame rail, approximately beneath the driver's seat. I'd suggest changing the filer, running a couple of tanks through it with some good injector cleaner mixed into fresh gas, and see if it clears up.

In addition to speedo gears being a LOT cheaper than GPSes, there's also the fact that many engine functions are controlled by input to the ECU (or, in newer vehicles, the PTCU) that includes reading the vehicle road speed and comparing it to engine RPM, vacuum, etc. If the speedo is off by 3 or 5 MPH at highway speeds it ain't the end of the world, but if the speedo is off by 20 or 25 MPH at highway speeds ... in essence, the ECU is being "tricked" and isn't operating the engine at optimum efficiency because it thinks you're going a lot slower than you really are. Doesn't matter much when you're trail crawling in first gear and low range, but on the highway you could be affecting the fuel mileage.

You are the only person I have ever encountered who thinks the control arm bushings is the place to start. Most people say "Track bar." I say "wheel balance." Other people say "caster angle." Take your pick, but don't try to present your guess as the ultimate solution. It ain't. My '88 Cherokee has 275,000 miles on the original control arm bushings, the front end clunks turning into driveways, one of the front tires is definitely out of balance, and I don't have death wobble. Next case ...

Try it again the way Brent (BLHTAZ) suggested. The hydraulic clutch can be a beast to bleed, and the way you tried to do it initially probably sucked a LOT of air into the system. Now you have to get that air out.

The O2 sensor does nothing during warm-up. On initial start-up the Renix system runs in "open loop mode," which basically ignores sensor input and uses a rich-bias, pre-mapped air-fuel curve. I'm pretty sure the O2 sensor is one of the sensors that gets bypassed because, in my '88 Cherokee, on cold mornings I can feel a stumble followed by a jump at the point when it seems to be about the right temperature to be switching into "closed loop mode."

Let me post this one more time, for the benefit of everyone who is willing to listen. Then I'll go fire up my desk chair and go take a ride around the front yard. There is NO single, works-every-time cause or solution for death wobble. NONE! It's a complex interaction. When I started working on the XJ Bible, I spent several months (yes, months) exchanging drafts of the proposed chapter on death wobble with a guy named Alyn, whom I considered to be the most knowledgeable guy in NAXJA regarding suspension design and geometry. Like me, he had some time in on race car chassis work, but he actually understood things like "roll center" that were (and are) essentially just words to me. It had always been my experience that the single most prevalent aspect contributing to death wobble had always been tire balance. Alyn reminded me that if only one tire is out of balance, you can sometimes drive down the highway for 50 miles and have no problem. Hit a bump, and you have a problem So it's more than tire balance. Then there are those who say it's caster (or lack thereof). Again, though, you can find people running far less caster than specified and they never have death wobble. Then there's the track bar crew. "DW is always cause by a worn-out track bar." Well, no, it isn't. Some years ago, in the middle of a cold winter (when we still had those), the track bar on the '88 XJ got so bad that I had almost a half turn of free play in the steering wheel before anything started to happen at the front wheels. But ... while steering was somewhat less than precise, I drove it that way for several months until things warmed up enough to crawl under and replace it, and there was never even a hint of death wobble. "It's the bushings" says ExJay33. The first (and worst) episode of DW I ever encountered was in a brand new, box stock 1999 Grand Cherokee WJ. It was six months old, had at the time about 8000 miles on it, and since I was wheeling the XJ it (the WJ) was my daily driver and completely, absolutely stock. I was headed down a long, shallow downgrade on a state road in New Hampshire at 55 MPH, lightly touched the brakes to hold the speed at 55 ... and all hell broke loose. I had to stop the vehicle to end it. I sold that piece of tin back to DaimlerChrysler at around 14,000 miles, but it never again exhibited death wobble. No worn bushings. No worn track bar. No bad alignment. Tire balance was perfect -- it rode like it was on glass most of the time. What happened? Alyn and I finally agreed that the problem is so complex because it relies on a harmonic. If one front wheel starts bouncing around, you have one front wheel bouncing around. Not good, but no big deal. But ... when the bouncing in one wheel hits a frequency that allows it to start the opposite wheel bouncing, and then they mutually feedback and reinforce each other in a constant escalation, THAT's when you get death wobble. And it can any of a number of factors that sets it off, or a combination of more than one. Regarding the WJ, I discovered that Jeep had a known (but unpublicized) problem with DW in export WJs. They fixed it by replacing the springs with a different rate. Mine had the optional UpCountry suspension. I assume the early U.S. spec UpCountry was the same spec as the European export suspension, but I've never been able to confirm that, and it doesn't interest me enough now to pursue it. What set mine off was warped brake rotors. The light touch on the brakes, combined with warped rotors, sent the caliper bouncing back and forth. That started the wheel wobbling slightly, and the suspension was just right to transmit that to the opposite wheel. BOOM! I had death wobble once on the '88 MJ, right after I had swapped the tires. Put the first set back on, and had no more death wobble. The frequency of oscillation of that particular set of tires happened to match the natural frequency of the springs in the MJ, and that's all it took. Dirreent set of tires weighed different and reacted different to the same road, so ... no death wobble. Alyn and I also sort of agreed that it's important to distinguish between things that "cause" death wobble, and things that may "allow" or "contribute to" death wobble but can't "cause" it. Obviously, since I drove around for several months with a badly worn track bar and had no DW, it cannot be said that a worn track bar "causes" DW. Ditto control arm bushings. Ditto the steering stabilizer. Each of those things may help dampen the transmission of wobble from one side to the other and thus replacing worn components may help prevent the onset of death wobble, but they aren't the "cause." Personally, I still hold the opinion that most of the time wheel balance is the real cause. However, I know there are instances when tires are perfectly balanced on a smooth road but hitting a bump can set off death wobble, so it's not ALWAYS wheel balance. But sometimes, like with my '99 WJ, it's going to be essentially built into the front suspension and it may be that only changing something will alter the dynamic. Different shock valving might offset a certain spring rate that has the magic harmomic frequency, for example. Increasing the caster angle changes the way the tires ride on the road, which is why that has an effect. It's not a simple problem. It's fine to offer suggestions as to what things to consider, but it's also important not to fall into the trap of claiming that YOUR one-size-fits-all solution is THE answer, because ... it isn't. I still always suggest tire balance first, but I long ago stopped saying that was the first, last and only thing you need to consider.

Since you misunderstood my post and you don't know jack about me, I don't know why I waste my time responding except to straighten out misconceptions for the benefit of those with an open mind. Yes, I have experienced death wobble. I know exactly what it feels like and why it is called what is is. I did not say that pinion angle has anything to do with death wobble. I said that caster angle has a lot to do with death wobble. But because the front axle is a welded assembly, when you change the caster angle you also change the pinion angle, and when you change the pinion angle you change the u-joint operating angle. Which means that, as one of the other gents correctly expressed it, when dealing with a lifted rig you are seeking a compromise that (hopefully) allows you to have enough caster to prevent death wobble while having a low enough u-joint angle to avoid excessive vibration and rapid destruction of the u-joints. Now, if you'll excuse me, I'm going to drive my computer chair down to Rausch Creek and play ...

True, but there is still a relationship, because when you lift you DECREASE the caster angle while you INCREASE the u-joint operating angle. The more you adjust the caster to try to get back the positive caster, the more you increae the u-joint angle. Once you get to about 4" of lift or higher, you basically can't run the correct caster angle without gobbling u-joints, so you have to back off on the caster and hope you don't have death wobble problems.

The lift increased the toe-in, AND reduced the caster angle. Caster is critical to avoid death wobble. Get it aligned.

I'm going to disagree with those who claim that the track bar is subject to such high stress that you can't use bushings, or you can't use sleeves, or you shouldn't use TREs. Yet y'all run drag links with TREs AND sleeves, and don't even think about it. Have I ever seen a track bar fail? No. I heard of one failing -- one of Rusty's, that had the threaded insert pull out of the tube at the TRE end. The insert was re-welded and all was good to go. The most serious steering failure I've encountered on a trail was on a winter ride with the club I used to belong to. One of the guys ran a ZJ with a pretty tall lift and 33s. There was a rock garden under the snow. I guess he got a wheel caught, and he ripped the steering box off the frame. Literally. No damage to the track bar. No damage to the drag link. But enough stress to break one mounting ear off the box and pull two other bolts through the "frame" (unibody) rail. All that stress was transmitted from the stuck wheel to the steering box through the drag link, with its adjusting sleeve. And now you want me to accept that a sleeve exactly like that isn't strong enough for the track bar in a street vehicle? BTW -- I like that bar Motion is suggesting. Looks very nice, if it adjusts short enough to work at stock heights. I guess Hornbrod has some lift, but I don't. The only adjustable short enough to work at stock height is Rusty's, and the bend in his is wrong -- it's an intereference fit with the front diff cover.

Of course you have this issue with heim joints. Most heim joints have the same range of movement as a TRE, or less. Whatever their range is, once they reach the limit the "collar" is solidly bound up against the bolt and something has to break -- just like a TRE that exceeds the limits of its range. Now, if you're talking about connecting the upper end heim to a totally different frame bracket so the direction of movement is different than that of a TRE, that's a different story. But if that's what you have in mind, the additional range of rotation is created by changing the axis of the bolt, not by any inherent superiority of the heim over a TRE.

We ALL run drag links with adjusting sleeves. What's the difference?

Failed 2 ...

Test 2 ...

Ummm ... isn't the one we need the one that DOES have the 'R'? The "old" (forward revolving) version is the one that fits AMC I-6 engines with conventional vee belts, all the way back to 1964 when AMC first introduced the 199/232/158 c.i.d. family of engines. It's the serpentine belt pumps that rotate "reversed." (I think). And the "wrong" ones will bolt in .. the block is the same.

Failed.