4.0 vs 4.0HO?

Let me get this right.... You are taking a simple fuel injection system that worked great for years and are wanting to replace it with a bunch of over complicated, 'really' expensive to fix Chrysler crap??

Just things like the emissions light or maint req light. On yours, you can unplug a module, on the fancy one you 'have' to spend at least $75.00 to have Chrysler turn it off, etc....

Then we can talk gas mileage. The 'fancy' system gets about 5 mpg or more less.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

James Morrow wrote:

it's not that simple. the HO model has the intake ports set higher up on the head. it's not just a computer swap. to do it right, you would have to get the head, intake and computer plus wiring off a junkyard jeep. you may have to get all the sensors too, like the cps, etc. google "4.0 head" or something like that.

I don't think what you'll gain will be worth the time or expense, however you do it, but I'm sure it could be done.

There was a Mopar fuel injection kit that was made to replace the carb and feedback system on the 4.2L Jeeps. I believe it was made by Hesco. I don't know how much is interchangeable with the 4.0L, but if you were willing to work hard enough, and spend enough, you could probably make it work.

I wouldn't do it.

First, I agree. It's not worth it. However, some of the claims you make are just wrong. As far as simple goes, the Chrysler is much simpler than the Frog system, and is much more reliable. Not to mention, the Chrysler system just flat runs better.

You always make such a big deal about this and it's really not even worth worrying about. Nobody holds a gun to your head and makes you spend money. On your Renix, you unplug a module. On the Chrysler system, you remove a bulb. What's the big difference?

You've done a scientific study on this?

Why would you want to do that if the engine you have is o.k? I replaced the screwed '91 HO engine in my YJ last year with a '89 LO engine from a damaged XJ. I did that because the HO engine is very rare on junk yards here in Europe. The difference in preformance is like not there. The swap took me a weekend and I would do it again any time.

If you say so.... My 88 has turned 300K km and runs great.

On your Renix, you unplug a module. On the Chrysler system, you remove a bulb.

Well there you go, you have 'really' nailed the difference in my thinking vs yours!

The big difference is that pesky one hour labor to look at anything! Here in Ontario Canada it is $79.00 or $86.00 plus 15% tax! A Cool hundred bucks!

You are 'forced' to pay this to reset a stupid timer that is an instant 'Fail' on an emissions test.

I mean seriously, how many folks feel competent enough to remove a freaking dash board to pull that bulb?

That is a 'major' job if you have never done it before.

Yup, I have issues with stupid crap like that!

No, I just have seen the new ones post their mileage here and I have had them come on 10 day trips with me and we compare fill ups at the same time....

Not scientific, but a 'real life' test on 'many' occasions over the last

5 years.

I am always lower for gas used volume in my Cherokee 4.0.

Then if I am in my CJ7 comparing it to the TJ 4.0, well they just can't believe it. I get radically better mileage running off road logging road trails, 10 liters difference in 200 km usually, let alone my sweet

19 US mpg or 11L/100km Canadian on the highway. I get a nice 24 US mpg in my Cherokee running empty. Fully loaded with 4 adults and camping gear, it goes down to 20 mpg or so.

There are a mess of folks from this newsgroup that can confirm this because they were the folks I was comparing to. It is no BS, bllsht.

Mike

I'm sure it does. I wasn't saying they run bad, just that the Chrysler controlled ones run better. Although as far as annoying repeating problems, the Renix system has many more.

On your Renix, you unplug a module. On the Chrysler system, you remove a bulb.

Tax on labor? You guys still trying to figure out how to pay for that free health care? ;-)

Can't speak on emissions testing anywhere but California, but an illuminated emissions maintenance reminder isn't cause for a failure. There isn't even a functional test for it in the inspection procedure.

Anyone who considers removing four screws in plain sight a 'major' job, shouldn't be complaining about having to pay to have it done. It's not exactly rocket science.

Too many variables involved to consider taking your claim seriously.

If you say so. The problem is you could drop 5 mpg just by changing drivers.