keep an eye on it
cold weather will not cause a a problem , but hot weather will cause a serious vapour build up in the fuel tank, that is what the evap system is for .

any mileage increase to report

 

Nope, no increase as of yet unfortunately. I'm hoping that plugging off the other line will achieve a few more miles.

 

In the old days there was no EVAP system, there was just a small vent tube to the atmosphere at the top of the filler tube just under the gas cap.

Some evaporation took place, obviously, but not enough to give only 10 mpg.
In other words, you don't lose that much fuel from just simple evaporation.
In order for that to happen it had to be sucked into the engine through the EVAP intake manifold port due to a faulty internal leak in that system.

And off course there's what Ron said, that much fuel being burned would foul the plugs, and there wasn't any fouling, but still, the possibility was there that the EVAP system was/is at fault.

 

Certainly not helping my case, though. I'd like to try pure 87 octane gas with no ethanol in it and see what I get.

 

you will to add some ethanol neutralizer to try that test

try 2 doses of stabil in your fuel tank before you fuel up

it says stabil neutralizes ethanol

 

One issue I see there: when ethanol is neturalized, it doesn't just disappear. I believe it turns into water, which must be dealt with, likely with another alcohol to absorb the water and allow it to be burned.

Aside from that, from what I've read, ethanol is added to boost the octane of gasoline, amongst a few other reasons. Hence why I mentioned pure 87 octane fuel, where no ethanol is added in the first place.


.....what are the chances of my fuel level sender itself being inaccurate, thus throwing off my perception of my mileage?

it seems accurate. When the pump shuts off, it reads full, right on the dot. Although I suppose that doesn't mean that when it reads 'empty' the tank is truly 'empty'. Granted, on a known good sender, E really isn't E, but it's close.

I'm wondering if it's reading empty too soon, by far, which would explain why I can't get over 200 miles to the tank full no matter what I do. No matter what the engine does, that sender is going to read whatever it wants to read.

 

There's a little red light that comes on in the dash, when you're running on fumes. (can't remember what it say, but it's red)
And you can't go by the gauge, you have to do my test, but just to the first click of course.

 

Would that achieve the same affect as filling the tank properly, noting the gallons bought, driving until empty, then dividing miles driven by gallons bought?

^ I need to start doing this. I've only gone by the trip odometer.

The light you're referring to is 'check gauge'.

 

I always fill up, zero the odometer, drive a half tank or more, fill up and note mileage and gallons bought right then. Gauge can be off and you know tires can cause mileage to be off. It's just a rough estimate. Maybe I do it wrong ?

 

What BeatnikRanger said...
@ A-Wolf, it may help to know the routes millage as you never know how accurate the trip odometer is.
It should be pretty close if your tires are stock.
If you really want to get OCD about it, have some friends and family drive the same route with different vehicles and take an average.

 

cameron , you might have to bite the perverbial bulltet and try 2 or tankfuls of 91 octane

to properly gauge your vehicles mileage

 

If it comes to that, I'd be happy to. Just need a bit more cash on hand first.

Also, note; there is a bit of an MPG increase so far. I've got ~66 miles out of a quarter of a tank.

@Jeff: Yeah, I should definately make sure the thing is accurate. My tires are the stock size with 15 inch wheels, which I assume are the factory wheels.

 

About tire sizes, look at the drivers door jamb, it will tell you there.
235/75 15.
Mine are that size, but on my door jamb, Mazda listed something different, but I can't remember what it says at the moment.

 

I'll have a look.

 

After 80-ish miles, I dropped below a quarter of a tank. Bear in mind I only had half a tank to start with.

 

my tires are the stock size according to the door jamb sticker, too. Took a few minutes to look.

 

+2 to this. Actually I think I recommended using a GPS unit that does this, I have to look back at the thread since I haven't checked on this.

EDIT: I did.

I see you stated you didn't have anything to calculate this. Do you have anyone that you know of that has a portable GPS? OR do you have a smart phone?

My $50 seven year old Garmin does this as far as showing mph/and then trip. Get on a stretch of highway. Go 60mph according to your speedo in the truck, and look at the gps. Is it the same? If not, then you can't go by the reading of your speedo or odo since it's going to be off from the actual distance being traveled (which might be skewing your horrible gas mileage.)

If you have a smart phone there are tons of free apps that do the above.

When I put bigger tires/wheels on my truck I was off by about 8-10 mph. Which then affected my odo reading. When I calculated the mpg it was off. I didn't realize this UNITL I got an ultraguauge and calibrated it. Then realized I was not off at all on my mpg but instead I thought I was because I was calculating what the odo was telling me even it was off.

But it does seem like it's looking better, which is good. Keep us updated.

-Nigel

 

My speedometer is accurate, I know that for a fact. Therefor I can reasonably assume the odo is at least ballpark accurate, too; although I don't have any comparison for that.

 

So far I've gotten 83 miles out of 4.7 gallons of gas. By my math that's 17.65 MPG. I love that. Not completely empty yet, either. I can probably squeeze 'er to 100. But hey, even if the check gauge light flicks on right now, I'm happy. I'll throw another few gallons in 'er soon. Hopefully at that point gas will be at the right spot for a full tank. Not complaining about less than 2.50 for gas, but I'll still pinch pennies if I can.

 

Final number was 98 miles before I put another 4.7 gallons in it. So, by my math (98 divided by 4.7) is roughly 20 MPG. Amazing.

My CEL did go off, btw. Code for the EVAP purge valve, as I expected. Took it long enough. So I guess I'm ripping one from the junkyard here soon. I just cleared the code so I don't have to look at it.

I'm likely headed to the junkers next week, so I'll ****** one then; which is the reason why I didn't get a full tank. I'll keep my mileage posted as I continue to drive.

 

keep us posted

 

NOTE about GPS. Unless you have military GPS. Like on there boats and in there tanks yadda. Your mileage will be off by 3 yards give or take. Even smart phones. We don't get exact GPS. Don't know why. Just know this to be true. My 2001 XLT has an 18 gallon tank according to owners manuel. When I got it it was on E. I filled it with almost 16 gallons. So that accounts for the extra gas below E. I think the book said 3 gallons hide below E. I would never bet on that. At the age of my truck. I almost expect the fuel gauge to be a little funky. For these reasons and environment. I don't count MPG. I always fill at half or before. I do understand the need to know the MPG. Only thing I can think to work best is a computer program on a laptop connected to the trucks port. I have been looking at the advanced meters. They still don't do MPG as I have seen.

 

I appreciate the info. Main reason I'm tracking mine, is because something was obviously wrong, especially now that I can get 100 miles out of a shade under 5 gallons. Basically doubled. Other than that, after I can reasonably confirm it fixed, I don't plan on tracking it regularly.

 

Ok cool. 20MPG is amazing. Its been a long time since I have owned a vehicle that gets that MPG. I usually 14-17. With high way and all. It was past SUV's. So maybe I should see what this little 3.0 V6 does. I know it will be better if I stop doing high revs to hear the glass pack rumble and pop. Always wanted on of those. Not a mid life crisses. Just got something I have been wanting for a long time.

 

I'm not easy on mine at all. That being said though, I don't abuse it, either. I try not to, anyway. Example, going up the on ramp, I floor the accelerator and get up to highway speed, merge into traffic and be on my way. This Vulcan forces me to do this, however. On the highway, my engine likes to run about 2,500 at around 60mph on up with OD on.

Although bear in mind, I'm giving mine every chance I can possibly give it. 14-17 really isn't bad for yours, though. Plugs and wires will go quite a ways, however.