Octane Booster?

[TacticalFats]

I noticed that I was getting some pinging under acceleration, etc, lately. Must be the "cheap" ($2.70/gal) gas. I added some "Octane 104" or something like that and the truck runs MUCH smoother, and actually seems to be getting better mileage (anything's an improvement over the 13mpg I average).

Anyone have an opinion on this stuff or is it snake oil?

 

[RichP]

No, it works as advertised, it works by retarding when the fuel is ignited by making it harder to burn. Question is what is the cost of a can of octane booster vs the next grade fuel at the pump. I have not priced the booster but when I had my 69 willys I ran a lead additive every couple of tanks to keep the 350 Buick engine happy and not destroy my valve seats, that was about $3 a can. Just do the math.

 

[langer1]

I noticed that I was getting some pinging under acceleration, etc, lately. Must be the "cheap" ($2.70/gal) gas. I added some "Octane 104" or something like that and the truck runs MUCH smoother, and actually seems to be getting better mileage (anything's an improvement over the 13mpg I average).

Anyone have an opinion on this stuff or is it snake oil?

13mpg you got some problems you need to fix.

 

[Sarge]

If your 4.0 isn't running well on the low octane then you have some motor problems which need addressing. Our motors shouldn't require any higher octane.

Sarge

 

[RichP]

Missed the milage thing, 13 is not good, you have something else going on there. I'd start with a good tune up, champion plugs, etc. Then I'd remove and clean the throttle body on the workbench being careful not to damage the TPS and map/mas sensor. From there I'd also do a good decarbonizing with seafoam or that BG stuff. After that you may find it's the O2 sensor.
Some XJ's, 99's that I remember, had this problem and had the ecu flashed but most made no change to the knocking.

 

[CherokeeDad]

If your 4.0 isn't running well on the low octane then you have some motor problems which need addressing. Our motors shouldn't require any higher octane.

Sarge

"Motor problems" like what? I have a '91 XJ (160k miles) and an '87 MJ (200+k miles) with the same pinging problems. We've replaced plugs, cap, rotor, TPS, OX sensor and a couple injector cleaner additives from parts stores and the pinging remains. Any experience/advice would be welcomed.

Also see the thread I started the other day on this subject. "Pinging Jeep 4.0L, need advice" http://www.naxja.org/forum/showthread.php?t=63792

 

[langer1]

"Motor problems" like what? I have a '91 XJ (160k miles) and an '87 MJ (200+k miles) with the same pinging problems. We've replaced plugs, cap, rotor, TPS, OX sensor and a couple injector cleaner additives from parts stores and the pinging remains. Any experience/advice would be welcomed.

Also see the thread I started the other day on this subject. "Pinging Jeep 4.0L, need advice" http://www.naxja.org/forum/showthread.php?t=63792

Have you tried a decarb? A pluged Cat is also a possibilty.If your engine burns any oil it will plug your Cat. Try a Sea Foam de-carb.

 

[Littlewhitexj]

what part of the country are you in? here i can buy 85 octane, but most other places the lowest is 87 octane, the jeep always gets 87, it dosent like 85.

 

[old_man]

Run a can of BG44K in the gas every 10K miles. It will clean your injectors and get rid of carbon buildup. Yes it is $20 a can, but well worth it. Don't even bother thinking of running STP or any of the other so called injector cleaners, they aren't even in the same catagory.

Make sure and keep your air filter changed.

 

[TacticalFats]

I just attributed the poor mileage to it being a brick w/ a big 6 cyl engine. I don't drive very aggressive, and the thing is completely maintained. Runs smooth. It doesn't "need" higher octane, but just seems to run better, although it already ran good. It just had a slight pinging under load.

Within the last 5k, I have done the cap, rotor, plugs, wires, air filter, Seafoam, trans flush, oil (syn), cooling system (with the OEM 195 t-stat), and replaced the TPS (thought a misfire was the Tps messing with the trans).

The truck has no lift, tires are inflated properly, and doesn't burn/use any oil.

The O2 sensor was replaced, oh, about 20k ago with an OEM unit.

 

[langer1]

I just attributed the poor mileage to it being a brick w/ a big 6 cyl engine. I don't drive very aggressive, and the thing is completely maintained. Runs smooth. It doesn't "need" higher octane, but just seems to run better, although it already ran good. It just had a slight pinging under load.

Within the last 5k, I have done the cap, rotor, plugs, wires, air filter, Seafoam, trans flush, oil (syn), cooling system (with the OEM 195 t-stat), and replaced the TPS (thought a misfire was the Tps messing with the trans).

The truck has no lift, tires are inflated properly, and doesn't burn/use any oil.

The O2 sensor was replaced, oh, about 20k ago with an OEM unit.

Do you know if you have the tow package? My old 87 get's 21mpg easly.

 

[Mikel]

A stock XJ with the 4.0 should get 20MPG at *normal* highway speeds.

 

[RichP]

I just attributed the poor mileage to it being a brick w/ a big 6 cyl engine. I don't drive very aggressive, and the thing is completely maintained. Runs smooth. It doesn't "need" higher octane, but just seems to run better, although it already ran good. It just had a slight pinging under load.

Within the last 5k, I have done the cap, rotor, plugs, wires, air filter, Seafoam, trans flush, oil (syn), cooling system (with the OEM 195 t-stat), and replaced the TPS (thought a misfire was the Tps messing with the trans).

The truck has no lift, tires are inflated properly, and doesn't burn/use any oil.

The O2 sensor was replaced, oh, about 20k ago with an OEM unit.

Just out of curiosity, what brand plugs cap rotor and wires did you use ? One of the things I have noticed here in NE Pa is that for arbritary reasons the stations here sell gas that causes milage hits on all 3 jeeps and the wifes Oldsmobile, usually has happended in Jan which is over two months after the winter fuel is already in use. I have noticed it happen about 4 times now.

 

[viperbaron]

Where can I get some BG44K here in Colorado?
I don't recall seeing it at the parts store(s).

 

[Ridr]

I have the tow package and still get 20 without problem