my Q is just that,


-What are the main things that effect the gas milage? (injectors, o2 sesor so on and so forth)

i am trying to get good MPG but i need to tune my safc still. just wanted to know what else would effect MPG

steven

 

Injectors
O2 Sensor
Compression
Spark Plugs / Wires

 

AFR would also be a big one right? but that is a contijant of an o2 sensor


what about mass air flow meter?(i guess you would feel that more)

 

How heavy your foot is

The o2 sensor runs in closed loop only at cruising speeds so for city driving it isnt too much help. Also how much vacuum your engine is pulling

 

tps?

 

Internal lubrication inside the rotor housings is also a biggie, as evidenced by wildy varying fuel economies using different ratios of premix that I've been experimenting with.

The greatest affect on mileage, though, is something you probably can't control- how many highway miles in relation to stop-and-go driving miles you put on her. Those of us that predominately cruise the highways get from 25 to 28 mpg+, while you city dwellers are overjoyed to see 16, lol...

 

so sad, yet so very true

 

yeah i get sucky gas milag on fresh injectors, im going to be buying a new o2 sesor...any rocomendations for widebands?

 

fresh injectors lead to BAD milage?? how is that possible??

so i shouldn't get my fuel injectors cleaned//changed??

 

No I think you misunderstood. If your fuel injectors are leaking or sometimes get stuck open gas mileage can be poor. Also if they are clogged the fuel will not be sprayed in the correct pattern or atomize as well as I understand it. Maybe I didnt use the right terms but I hope you get the idea.

 

So would getting a aftermarket ignition box to increas spark have a positive effect on MPG? Same question concerning spark wires?

Also, does a O2 sensor being new or old effect MPG? Or is it just if the O2 sensor is functioning correctly? In short, will a functioning 10 year old sensor work as well as a bran new one?

 

Weight and gearing. Actually, I apologize, that's sort of a really general remark that you can't do much about, but it's true.

 

Most likely a 10 year old sensor will not be functioning, especially with the seven and its higher than average heated exhaust gas. There is a test I believe in the haynes that you can do with a voltmeter to see how much voltage the o2 sensor is sending back to see if its bad. So if its 10 years old and the check see's it as ok with volts and all, then a brand new one will make no difference.

Timing is another huge thing related to fuel emissions. Timing effects the life and output of the o2 sensor, if your timing is off and your exhaust gases contain more gas left unburnt for example, not only will this heat up the o2 sensor and shorten its life, but it will also give it a rich reading, reducing your MPG.

 

i still think how hard you are on the gas makes the biggest difference.

 

don't forget about alignment and tires. should your alignment be slightly off or tires be under inflated by air then you'll have suckier gas milage. due to extra drag caused by the defishencys.

as for all the other ones mention. i will attest that it is true. and it all helps out if you update all the other stuff to compliment each other.

i switched over the a 15-50 full synthetic, also i replaced my Pully, bought new tires, got my alignment in check, new sparkplugs with the bushing removed, new sparkplug wires, Extra grounding, Re-specked the TPS.

next on my list will be to buy a new O2 sensor. and new vacume hoses.

so far im getting about 26 miles to the gallon on highways and about 20 miles on the streets. also I have a bigger foot then shaq. i always redline my car a dozen times every day just to feel the power of it's engine. and so far it's been good

my compressions come out 105 front and 97 rear on a 146K stock motor.

you have to take care of your car for it to take care of you.

 

I'm going to pick up a new 02 sensor tomarow, they're only $20 for a universal setup and i think it'll get me some good mileage again.

 

Bosch Universal O2 sensors are $7 from Olympic Auto Parts

I thought you could get better fuel economy from advancing the timing as well (At least on piston cars)
I dont think it was listed, so I will: free-er flowing intake and exhaust, the less work your engine has to do to get up to, and maintain speed, the better fuel economy you are likely to get.

If you do a lot of city driving, weight is going to be more likely of a factor in your MPG calculations. The hevier you are, the more effort to get you up to accelerate at the same rate.

 

Sombody mentioned the TPS.

When it is set right, the ECU gives a fuel cut during deceleration.

 

Wow, I'm getting an 02 sensor asap!

 

Yeh, you just have to splice in the wire from your old O2 sensor. I've read some stock wires have sheilding on them (Never seen it myself) so be careful not to let the sheilding wire touch the O2 wire.

 

as i have herd it put on another forum "the nut behind the wheel" is the biggest thing you can change, i have got 10+ mpg difference with my driving habits. take your time, don't romp on the gas. look up hypermiling, some people take it to an extreme but even the little things you can do makes a big difference.

 

Don't pick up Fat girls!

 

I would say friction. Be it road, air, or from moving parts. Only if magnetic bearing where able to support the weight of a car, or take the stress from internal combustion.

 

First and foremost, the biggest effects on mileage come from keeping the car and driver in tune. The NA FC got about 24MPG in EPA testing back in the day. Few drivers get that today due to poor maintenance/driving habits. Once you have a car in good shape you can look at improving flow/reducing friction/reducing weight. My old FC with careful maintenance, synthetic lubes, a TON of intake and exhaust work and a fair bit of lightening got 27mpg cruising on the freeway at 60-70mph. It still got 21-22mpg at 100mph. Driving it around town being a nitwit usually netted me 12-14mpg...

 

First and foremost....WTF are you clowns doing?!?!

This thread is from 2005

And there is a more detailed and relevant thread right on the front page