fountain

Alright....got a 94 regular cab 4 cylinder running 33"radial scampers with 4:88 gears. I just regeared with high hopes of gaining some extra mpg's. Well im 2/4 of the way through this tank with 170 miles logged...first tank since the gear swap.

Now I don't think my speedometer is reading fast..running 70, but doesn't feel it. I need to check it with a gps.

So, what's the deal here...am I bout right for mileage or too short? I have been reading on here where some are 250-80 per tank with my set up.

abecedarian

170 miles and 1/2 of a tank in? Sounds like you're on target for around 300 miles for the tank.

It would also depend on what tank you have- there are several, and what the capacity is.

fountain

I meant 3/4...0nly 1/4 left and im pretty sure i have a 15 gallon tank. Before the gear swap I was averaging bout 14.9 mpg with everything other than 33" swampers

fountain

Just filled up....whopping 14.3....definitely not what I was hoping for with the new gears

TNRabbit

Hold many miles on your O2 sensor?

Any vacuum/intake leaks?

TPS adjusted correctly?

abecedarian

Definitely check TNRabbit's suggestions. A bad O2 sensor may not throw a code, btw.
It wouldn't hurt to check your air filter, valves and ignition timing too.

How'd you make room for the 33's? Body or suspension lift?
The bigger tires and whatever else done so they fit could be causing additional drag / wind resistance. Do you have a skidplate installed?

Junkers88

?? May not throw a code? Crap how do you go about testing that thing? Or is it cheap enough just to replace it?

fountain

Good question!

abecedarian

What we would use to test- O2 output swings 8 times in a minute when heated by a propane torch isn't what the ECU checks. The ECU samples the O2 sensor and if it reads as lean or rich for some time, the ECU tries to compensate, and if the O2 keeps reading rich or lean despite the ECU attempt at compensation, the ECU will throw the code for the condition.
If the O2 happens to fail while the mix is "normal", the ECU won't throw a code.

Junkers88

Crap. I'm running so rich right now I'm down to 13mpg from 20mpg and can burn a flame at the exhaust tip with a cig lighter. Hoping that a change in O2 sensor and the EGR valve temp sensor might help that issue. Tired of wasting fuel.

TNRabbit

If your O2 sensor has more than 100,000 miles on it, you need to replace it.

fountain

Well my exhaust tip is blackened on the outside fringe. I know there can't be much to replacing it, but what can I expect to pay for one....and also if its rich, what do I do too fix that?

I like my little truck, but lack of room and bad mileage is making me lean towards something else. Maybe I have a few small things that I can replace like the o2 sensor and will help

Junkers88

Fountain,
I went and priced an OEM replacement at the local auto parts place and the damn thing is 100$. If I get that and the EGR temp sensor that I know is bad on mine I'll be spending over 200$ on two little parts. If I knew for a fact that'd fix my mixture issue I'd do it in a heart beat. Those are the only two things I haven't done other than checking the TPS and I can't do that until I can find a place to rent a multi-meter.

Junkers88

*laugh* So I'm guessing since mine has 244K on it I might need to just go ahead and replace it?

TNRabbit

www.sparkplugs.com sells Denso & NTK O2 sensors for @ $70.

Also, call Gary Smith (link in my sig) & see what kind of price he csan get you on those. It WILL be cheaper.

Dude, these trucks are getting OLD; stuff wears out. Part of the cost of owning a vehicle. It still beats the ˟˟˟˟˟ out of the cost of a new truck payment~

fountain

Another question...what mpg should I be sitting around +/-? Just wanting to know how far I may be off

93Xtra-Cab

Did you factor in the odometer difference caused by the larger tires? The 33 is a larger diameter tire than the stock 225 or 31, therefore having a larger circumference. This means you travel a longer distance per axle rotation.

When I went to my 32s, I figured that for every mile my odometer said I traveled, I was actually going 1.0667 miles, based on my calculations. That little bit of difference is actually pretty significant once you go to fill up.

You probably did, but I'll ask anyway, did you calculate based upon what the gas gauge stated or the actual amount it took when you filled up? I once calculated by the gauge and i got like 12 mpg

waynesworld

RockAuto.com sells Denso o2's for cheap,i got one for less than 50bucks

fountain

I calculated by the trip meteor and the gallons I put in.

abecedarian

Not necessarily.

A well maintained vehicle won't foul the O2 like a neglected one will.