BETTER GAS MILAGE !!!!

[guggy]

Hi everyone i'm currently getting 18-19 mpg on my 98 limited sohc.
I was wondering if there is a way to clean the O2 sensors to bump up the milage further.

I have a 3.55 gears and 159,000 kms (Canada) on the truck and it seems to be getting a good milage !! (But i want more milage).

Any suggestions would be helpful !!!

 

[blinkgi]

g milleage

If I was getting 18-19 mpg I would be happy. Iam getting 15(as are alot of other drivers). Iam going to throw on an O2 sensor for $28 and it is supposed to boost up to 20mpg(supposedly).

You should try doing this. I heard that you are supposed to replace these like every 10k miles, but I sure didn't know that. Isn't to expensive to replace, don't clean it

 

[Rhett]

You are not supposed to change just 1 O2 sensor at a time. You're supposed to change both upstream, or both downstream, or all of them, (depends on your model year). Otherwise you can get screwy readings from one side of the manifold vs. the other side. So then it is a lot more xpensive than $28. $28 is cheap for an O2, for my 94 they are $45 each.

 

[Goober]

I paid $36 for my 02 sensor(Bosch), so $26 is pretty cheap. Didn't really notice any real significant mileage changes. Also, the 02 's are changed at around 60,000 mile intervals(accor. to my book-newer models may differ), not 10,000 miles. Good thing too, the newer models have 4 of them.

 

[Leford]

In the city I have 10 MPG in highway 22 MPG, I only use Shell fuel 95 octanes with 16% of alcohol, Shell Oil Helix Plus 10w40<br>My X 92 sport have 200.000 miles and still works wonderful!!

 

[yob_yeknom]

On 96+ vehicles, O2 sensors are designed to last over 100,000 miles.

 

[IAmTodd]

In the city I have 10 MPG in highway 22 MPG, I only use Shell fuel 95 octanes with 16% of alcohol, Shell Oil Helix Plus 10w40<br>My X 92 sport have 200.000 miles and still works wonderful!!

Why are you running 95? Unless you have a chip you should only be running 87. You could be harming your engine.

 

[XvjimbovX]

I have a 95 ohv with 115,000 mile just replace the o2. around 1000 miles aog and im still getting 13-15 around town

 

[WDP]

I have a 96 OHV that had the CEL light on for 4 years. Code read right bank O2 slow response. Pa. no longer sniffs the exhaust for emissions but reads the computer. The car always passed on the low side and had great power and 18- 22 MPG. Had to replace the O2 sensors to clear the CEL, mileage is down to 16-18. Moral of the story- don't replace them till they throw codes and don't expect to get more mileage with the change. They are toooo expensive to toss before their time.

WDP

 

[huskyfan23]

You are not supposed to change just 1 O2 sensor at a time. You're supposed to change both upstream, or both downstream, or all of them, (depends on your model year). Otherwise you can get screwy readings from one side of the manifold vs. the other side. So then it is a lot more xpensive than $28. $28 is cheap for an O2, for my 94 they are $45 each.

I think '91 models only have 1 o2. $28 is real cheap, hopefully it's Bosch.

 

[N2MUDN91]

How's 23.6 mpg on 31" tires workin' for you guys ? Let me change my plugs (dont remember the last time this took place), and change the 02 sensor.. My a/f is off so I think mines bad as it is.

Shane

 

[huskyfan23]

You get about 24 mpg? I average 17 with mostly freeway driving, though I used to get 10 a year and a half ago.

 

[frickea86]

i'm around 17 to 19, depends on my foot and the terrain....

 

[cfkane]

Why are you running 95? Unless you have a chip you should only be running 87. You could be harming your engine.

I am curious why running higher octane fuel would harm the engine. Octane defines a resistance to knock so I am wondering how a higher number than specified would cause damage?

 

[CHuntMD]

Octane is a additive to gas to slow the burn and raises the temp need to ignite the fuel. High compression engines will denoate early if using low octane fuel. Running a engine w/computer that is designed to run 87 but your using 93 will cause incomplete fuel burning. But don't take my word... read more here

http://auto.howstuffworks.com/question90.htm

By using higher octane fuel than recommended the fuel mixture will not burn completely and can cause carbon buildup, valve and O2 sensor issues (from what I've heard) You could also be masking engine problems by running 92-93 vs. 87. If your engine pings on 87 and is designed to run 87 and you have done nothing to increase the compression (like add a turbo or SC) then there is a computer or engine problem.

Both my 94 OHV and 97 SOHC all over 125,000miles run 87 exclusively.
Chris

 

[cfkane]

My question was slightly rhetorical in that this is a common misconception. In the many years of engine performance research and testing for various manufacturers I have heard a wide variety of theories relating to commercially available fuels that are not technically substantiated. The information you cite in “how stuff worksâ€￾ has been designed for the casual reader and is incomplete at best. In fact the resistance to knocking that octane provides does not change the flame front propagation significantly within the same basic fuel types such as those being discussed in this thread.

The requirement for octane is merely one of preventing uncontrolled flame propagation. With a constant test condition differences in octane are insignificant in terms of engine performance and are very difficult for most facilities to measure accurately. Where higher-octane values come into play during the test process is during mapping of spark advance, variable valve timing, or variable compression ratio. Test will typically begin using 98 octane Indoline and then move up or down depending upon the specific requirements.

I would recommend that you refer to a more comprehensive and technically accurate source of information such as “Internal Combustion Engine Fundamentalsâ€￾ by John Heywood of MIT. In it the process of determining octane via ASTM D-2699 and D-2700 are described. This explains in detail the factors that contribute to knock and the process used to derive octane for a given blendstock.

Bottom line to octane and the use in passenger cars is that use of a higher octane than needed for a particular application is just an excess expense with no significant detrimental effects and the only benefit being higher detergent additives in a few brands.

 

[CHuntMD]

I'm just relaying what 99.9 of the forum members would releate to IMHO. If any forum member wants to find more then google has all the chemical crap.

As for "no significant detrimental effects" I'll disagree.

According to GM
http://www.gm.com/vc/women/sm_qa.html

A: Octane is resistance to the burn or detonation of gasoline. The rating indicates how much fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than a spark from a spark plug, your engine will "knock." When vehicles were built with carburetors, knocking, or the premature ignition of gasoline, could be solved by using a higher- octane/slower-burning gasoline. Today, however, fuel injectors and computers accurately control air/fuel mixture. Thus you should use gasoline with the octane rating recommended in your vehicle's owner's manual. Using gas with an octane rating higher than recommended by the people who engineered your vehicle will not eliminate a knocking problem; it could cause your emissions system or catalytic converter to malfunction; and it is a waste of money.

Also, how about calling Pat Goss on Saturday 11am-3pm EST at 800) 636-1067
And seeing what he says.
Chris

 

[cfkane]

Read Heywood