1998 Grand 8 cyl 5.9

It's true. The 5.9 needs higher octane but only if your getting ping.

Run it on the mid octane and if you get any pinging then add the higher octane till it goes away.

Works like this.

1/2 gal of 87

• 1/2 gal of 91

--------------- is 1 gal of 88

octane works in direct proportion.

p.s. gasoline is gasoline, there is no "premium" just additives and octane booster that contrary to what some say actually lowers the combustibilty of the fuel.

I run (on average) 92 octane. Which I get by pumping in alternating fillups of 93 and 91 octane fuel.

I do a gas mileage and performance test.

I run a tank of regular and see what happens. In my CJ7's case the sucker won't go over 65 mph, rattles like crap and only gets 250 miles per 76 liter tank on regular. When I switch to premium, 3rd gear will do 70+ mph, 4th buries the speedo and I don't have any urge to see what

5th will do. I then get 350 miles easy to a tank full. (I am comparing tankfulls on long trips here, we put 3000 miles on the CJ7 this summer on one trip)

With my Cherokee, it makes absolutely no difference at all.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

^^---89 That is IF I actually could do math in my head. :/

The 5.9 came programmed to run premium, but can be reprogrammed to run on regular.

Thanks to all who responded. I will use regular and see what happens and the mention about reprogramming will take care of any problem. Ed. Kelly

"Ed" wrote in news: snipped-for-privacy@i3g2000cwc.googlegroups.com:

The need for premium is determined by combustion chamber design and compression ratio, it would be more accurate to say it's designed rather than programmed. If you run regular the engine will knock, you won't know it because the knock sensors will retard the spark which will reduce gas mileage and performance. If you reprogram the computer to limit the spark advance (and there's no need to do so, that's exactly what the knock sensor will do for you) you'll accomplish the same thing, a loss of power and a reduction in gas mileage.

Read Mike Romain's post where he says, "I run a tank of regular and see what happens. In my CJ7's case the sucker won't go over 65 mph, rattles like crap and only gets 250 miles per 76 liter tank on regular. When I switch to premium, 3rd gear will do 70+ mph, 4th buries the speedo and I don't have any urge to see what 5th will do. I then get 350 miles easy to a tank full."

That may be a little more extreme that the results you'll have but you get the idea, you should run premium.

We too have a '98 ZJ 5.9 Limited. Gas prices were higher when we bought it than they are now. It is a 'weekend and trip' vehicle for us, not a daily driver. Both of our daily beaters are Hondas.

It seems that middle grade gas might be OK but since our use of the beast is limited we don't mind paying for premium. FWIW I was told that the computer can be programmed for lower octane gas.

If you experiment with the different grades of gas I would appreciate hearing your experiences.

Since I'm asking for your opinion, I would like to know about your shock absorbers. I asked here about a month ago about what to put on my beast. I went with the Edelbrock Performer IAS's. I am happy with them but only have the originals to compare with. What shocks are on your ZJ? Do you like them? Why / Why not?

Thanks, dj

"Doug" wrote in news:AfmdnVf8_57eqJbYnZ2dnUVZ snipped-for-privacy@comcast.com:

Correct, but as I said, it's a waste of time and money. The knock sensor will do exactly the same thing, retard the spark with exactly the same results, less performance and less gas mileage.

It's probably cheaper to run premium.

Some engines have low compression kits available for them, I'm not sure the 5.9 is one of them. They may consist of low compression pistons or different cylinder heads which are VERY costly and it would take years to make up the cost in savings on gas price or there may be thicker head gaskets available, still costly because of the labor involved but much less than the other means of lowering compression...

Again, it's cheaper to run premium and make sure your *next* vehicle runs on regular.

As for shocks, I have a lift mounted on the back of my Jeep to carry a mobility scooter so I needed to get air adjustable rear shocks, that very much limited my choice, I just got what was cheap.

My dad has one of those 'go-karts', and it is difficult for my mom and sister to disassemble it when they go on a trip.

What lift do you have? Wish you'd gotten something else? Thoughts/comments?

"billy ray" wrote in news:6b73f$450c32d1$422afc51$ snipped-for-privacy@FUSE.NET:

I know, I tried that for some time, finally gave up as my arthritis got worse and got the lift.

I bought mine used and added the swing away option (it also was second hand).

Mine is the same as the current Ultra model but does not have the automatic tilt feature, that's not a problem because there's more than enough clearance.

No, I'm pretty happy with it and I've compared it to others that I don't like as well because of cheaper construction, less convenience, etc. Note, these are personal opinions.

Thought: I'd like some potato chips to go with watching football on TV, you got any?

Comment: There's lots of ways to carry a scooter, the outside lift such as mine is far and away the easiest to use for the least money. It also creates problems, the vehicle sticks way farther in back when the scooter is loaded and is harder to backup, many vehicles will require air adjustable shocks (lift weighs about 100lbs, scooters can weigh as much as 225lbs although most are under 200lbs.

Another comment: Where's those potato chips?

Those look nice and I'm sure Dad would get out more if they could easily load up his go cart.

I had thought of modifying one of those cargo haulers that you slide into your 2" receiver so it could be readily mounted/dismounted.

"billy ray" wrote in news:21ddc$450c7dce$422afc51$ snipped-for-privacy@FUSE.NET:

It's really worth the extra bucks. With the lift he lowers the lift, rides the scooter on to it and then has to get off because the lift can't handle the extra weight. He raises the lift and then gets into the car/truck/jeep/etc. and drives off. At his destination he does it in reverse order.

Notice the ONLY time he has to stand or walk is from the scooter to the lift to raise it (eliminated if he swivels the seat around, he'll be getting off the scooter right at the lift switch), then to the vehicle to get in and during that time he has plenty of things to hold on to if he needs a little help.

Even I can manage that and plan to be able to for many years. When I can't stand or walk at all I'll consider options...

Dad would buy it in a minute if the dog needed it, If mom had trouble getting around he'd buy one of those special vans.

The only way we were able to get him to use a properly designed cane was for his $5 model to disappear one night when he was asleep.

Darn cheapo Germans.....

It will ping if you run regular without reprogramming it.

Nice advice except for one small problem. The 5.9 doesn't have a knock sensor. It will happily ping it's self to death if you run regular without reprogramming it.

bllsht wrote in news: snipped-for-privacy@4ax.com:

No knock sensor? Is it fuel injected?