i told him he should get a brand new one from them this year bc they are suppose to be better engines but i haven't talked to him since it was on the tow truck for the 3rd engine

 

What is IFS and why is it such a poor automotive design flaw?
Is jeep the only maker that suffers from the ills of this IFS?
If its such a bad thing, why don't they just get rid of this so-called IFS?

 

What is bad about the powertech motors? When did they retire the 4.0l?
I know lots of people with modern jeeps and have never heard of outright engine replacements...
This sounds like internet hyperbole....I do think modern cars have more planned obsolescence built in...
There's no money in making a car that lasts 20 Year s

 

Except 4-door JKs are almost as big as a K5/Bronco/RamCharger. A narrow track width, short wheelbase and low roof height compared to ground clearance are major factors for our XJs' trail nimbleness.

 

It just means it's independent front suspension rather than a solid axle. It's not a bad suspension design for on road use, but off road it sucks.

Jeep stopped using the 4.0 in the Wrangler in 07, the Grand Cherokee in 98 and no newer Jeeps have ever had it. The WJ (99-04) Grand Cherokees had a 4.0 i6, but it was a different motor than the older 4.0s.

It takes a lot more work and money to replace a modern motor than it does in a 20 year old design vehicle so it's not as common. Very few people are going to go out and buy a new $30,000 Wrangler to turn around and replace the entire drive train.

There's definitely planned obsolescence, but a lot of it is keeping up with government safety and environmental regulations. A big problem with the modern Wrangler is government mandated safety features that really limit performance. Biggest turn off for me is the traction control system. It can be disabled but it's a pain to do and it randomly will come back.

 

lol no they're not. The 4 door JK has a bigger wheelbase than the XJ and is really similar in size, but slightly wider. It's also got more stock ground clearance than an XJ does.

I have an 85 Ramcharger and it's nowhere near as small as a 4 door JK is. Hell the interior of a 4 door JK has less room than my XJ does.

 

IFS is Independent Front Suspension. Instead of a solid axle each wheel pivots around a fixed point on the chassis - with double-wishbone suspension this means pretty much "moves enough to go over bumps"
Nothing's wrong with it from a technical point of view, it's a actually delivers a nicer ride. However you get waaay less articulation over a solid axle, which will let your Jeep work its way over many more types of obstacles. Most everything in this thread would be impossible without IFS: https://www.cherokeeforum.com/f59/flex-pics-8756/ (Actual wheeling shots, not poser "I'm on a curb" shots like I take lol)

Chrysler branded the 4.0L PowerTech as soon as they added their own electronics. In terms of the 4.0's engine management there are three major versions and two variants:

- 4.0L Renix: Renault/Bendix, 1987 - 1990 (XJ, MJ)
- 4.0L PowerTech Chrysler OBD-I: 1991 - 1995 (XJ, MJ, ZJ, YJ)
- 4.0L PowerTech Chrysler OBD-II: distributor from 1996 - 1999 (ZJ, TJ, ZJ, WJ), coil-on-plug and 4x O2s from 2000 - 2006 (WJ, TJ, LJ)

The I6 was discontinued largely because Chrysler couldn't and/or wouldn't adapt it's design to meet modern fuel economy and emissions expectations. Much of the tooling was still original when they shut down the factory.

In terms of suitability, the I6's perception was even worse as they shoehorned it into the Grand Cherokees. Not enough power to move these beasts. So a lot of those vehicles wound up with the V8.

In terms of direct replacement though, in 2002 Chrysler put their 3.7L V6 into the KJ platorm. Reliability issues aside, as far as I've managed to tell it gets about the same fuel economy as the I6 and puts out less power. One of the hallmarks of the 4.0L I6 is low-end torque for doing grunt work. Despite improvements to overall power output the 3.7L lacks that torque at lower RPM that wheelers seek. All of its power is made above 4000 RPM Being used in Dodge Caravans as well it was quickly deemed "gutless minivan POS"

Then the JKs are even heavier... same engine really unless you got a hemi or a new model with the PentaStar. Apparently there are some reliability issues with it but my own hearsay has been positive WRT the engine itself. Aside from random occurrences, which are expected in the first couple of model years, it's too early to really gauge reliability. But I still think Chrysler is a bunch of tools that can't assemble a decent vehicle worth ****.

 

Traction Control & Stability Control are government mandated???? :|

 

No, sorry I worded that weird.

 

Is the crappy 0331 head from the 2000-01 XJ's also used on all the post-01 Jeep Liberty models?

 

Thanks for the clarifications.
I definitely can feel the low end torque in my 1998 4.0L i6.

Salad, are you sure the old 1990s engines are called PowerTech? Everyone on these forums only says that the 1990's "Powertech" XJ engines are bulletproof. Goes to 300k and has torque, as you said. Why did the earlier poster say these "PowerTech" engines are bad? Or did he just mean the NEW post-2001 "PowerTech" engines are not as good? This says Powertech is post-2002, which would make sense. http://en.wikipedia.org/wiki/Chrysler_PowerTech_engine

Bottom line, it sounds like post-XJ Jeep are fine for Soccer Mom roads, but have lost the off-roading essence that Jeep purists identify the brand with.
1) Engines are not as bulletproof reliable as the old 4.0L i6
2) Less torque
3) More emissions limits
4) Suspension

 

I don't know much about IFS, but it seems like it would make for better off-roading. Each wheel can do its own thing. Isn't that what all those "parked on a curb" photos are trying to convey? One wheel is totally out of whack with the rest of the Jeep. I'd think IFS is what this is all about.

 

If you have an awesome set up ifs can be amazing, and but it takes MONEY! All those flex shots actually show how your suspension can work while keep four wheels touching. The better the flex the bigger the obstacle is that you can conquer for lack of a better term. Standard ifs doesn't allow for as much wheel travel. Especially upward travel.

 

No the liberty never had a 4.0

 

Google ifs vs solid axle. You get alot of info to help answer your questions