Spontaneous high mpg? (1 Viewer)

[feralyouth]

So I received bought a 95 4.5L and it had the typical mpg, this thing drank gas. Anyways I go to get it smogged and it passes everything but the egr test. Smog guy said it wasn’t holding vacuum, so I replace it and it failed again. He was a bro and passed it, but said to comeback when I fix it to check. Got a vacuum pump and found it was the egr modulator valve. Didn’t replace it yet…
Anyways wife wants to got into the mountains to camp, so I the 31s with the 33s off of the taco and hit the road. On the way to the mountains we got typical mpg. On the way back it seemed like the gauge was broken. Got home with half a tank. About 150miles…
A week goes by and the wife hits 100miles and the gauge barely moves. So I test it by filling to the 3/4 line and drive to the ¼ (I have obd1 so I don’t have a reader). Any was I get 253 miles off half a tank, that’s 20 mpg??? What the hell is happening?!

 

[family80]

Either your gauge is not functioning properly or everyone here is going to want to know how to duplicate your condition

 

[alia176]

31 vs 33 tires, did someone forget to take into account the correction factor? Stock size is 32".

 

[feralyouth]

31 vs 33 tires, did someone forget to take into account the correction factor? Stock size is 32".

Either your gauge is not functioning properly or everyone here is going to want to know how to duplicate your condition

That’s what I’ve been thinking but here I am 80 miles more at about 334. By all means I should be empty or close to it with regular mpg.

 

[feralyouth]

31 vs 33 tires, did someone forget to take into account the correction factor? Stock size is 32".

31 vs 33 tires, did someone forget to take into account the correction factor? Stock size is 32".

Well I am kinda retarted so no I didn’t take that into consideration. The guy bought it from had 31s on it. Anyways even if the miles are wrong due to the size, the mpg is still noticeable higher. It’s so noticeable that even the wife is commenting on it, and she is usually oblivious to these things. So let me ask you, am I retarted?

 

[Malleus]

I doubt it. Mine started getting ridiculous mileage on long trips this summer. 18-mpg. 11-mpg in town. Original everything. Pretty good for a 28 year old engine, especially since it didn't get that when new.

At first I thought it was pump gauge failure, but I've filled up at different pumps and got the same thing. 2+ hours on the road and mileage is great. Less and it's pretty normal.

 

[Kernal]

"am I retarted"

Maybe, because you sure can't spell

jk

FWIW the acceptable term now is "intellectual disability"

You can't say someone is retarded without risking the word police banning you from further human contact.
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Best MPG I ever got was when stuck on a straight level road with a speed limit of 45mph and no chance to pass. MPG worked out to 19 MPG for that stretch of road (about 100 miles). Best average HWY MPG I've gotten was 16.7 MPG when the engine was relatively new with low rolling resistance passenger rated tires. Same engine now with new plugs, air filter, and different tires (still P rated) is 14-15MPG highway.

 

[feralyouth]

"am I retarted"

Maybe, because you sure can't spell

(FWIW the acceptable term now is "intellectual disability").


Best MPG I ever got was when stuck on a straight level road with a speed limit of 45mph and no chance to pass. MPG worked out to 19 MPG for that stretch of road (about 100 miles). Best average HWY MPG I've gotten was 16.7 MPG when the engine was relatively new with low rolling resistance passenger rated tires. Same engine now with new plugs, air filter, and different tires (still P rated) is 14-15MPG highway.

Honestly I’m dyslexic as s*** and it gets way worse when typing on a phone. I was also typing in between sets at the gym haha. Anyways, you know what I was saying lmao.

Huh well I’m talking combined town and doing 70 on the highway. I never calculated mpg before and it didn’t seem to change when I put the 33s on a few days before. As soon as we started coming home from the mountains everything changed. I mean it is significant. Motors got 166k with no rebuilds.

 

[SpenserAK]

l

 

[LandLocked93]

Can't speak to your experience but can say my experience has been...
...over 20mpg (~21, corrected for tire size, ~ 2.5%) on a 290kmi engine in an unloaded '93 on flat ground interstate @ 65mph 90 miles in one direction, between CO Springs and Trinidad, on 33s. Closer to 19.8mpg both ways.

THEN...on trails with full load out weight... something like 1.1GPH, roughly 10mpg.

Bottom line, it makes fuel consumption planning for a multi-day run a total bi**h. lol

 

[ppc]

So I test it by filling to the 3/4 line and drive to the ¼ (I have obd1 so I don’t have a reader). Any was I get 253 miles off half a tank, that’s 20 mpg???

The method you used is the most inaccurate way to calculate MPG. Always start with a full tank where the stations pump click off. Reset you trip meter to zero. Drive as normal. When it's time to refill, if you can use the same pump so much the better as different pumps have different cutoff points. Fill again until the pump clicks off. Calculate MPG by dividing miles traveled by gallons pumped. Calculation accuracy can be improved with multiple fill-ups by totaling miles driven dividing by total gallons used.

 

[LandLocked93]

Calculate MPG by dividing miles traveled by gallons pumped. Calculation accuracy can be improved with multiple fill-ups by totaling miles driven dividing by total gallons used.

...again, as mentioned, from the same pump if possible.

 

[effjay80]

I've exceeded 20mpg on the ~350 mile drive on 80 east across wyoming from Evanston to Cheyenne when the wind is howling from the west, which it often is. External factors can make a huge difference.

 

[Heckraiser]

"on the way back from the mountains" might be a big clue here. You were going downhill, lol.

BTW, my 80 always got it's best mileage in the mountains. Even if you have to charge up the hills in 2nd gear, you're coasting and using basically no gas the other half of the time.

 

[Brindleboxer]

I just did a 500 mile roundtrip and pulled 18.2 mpg. I ran it at 65 and went up to around 70 when I needed to pass. Needless to say I was not expecting that number as in mixed driving I get 12.6 as long as I am not jumping off the line at every stop.

Odd question but since you are referencing the gauge does your truck have the stock tank and not an aftermarket (larger) or second tank?

 

[Marvelicious]

I don't know... sounds like a serious condition, but I'm sure someone on here would take it off your hands before it causes any major headaches.

For what it's worth, I've been watching the "instant MPG" using the Torque app on my '96 and while it's not really useful as a prediction of overall mileage, it can give you a clue on how your driving is changing things. Basically, what I've learned is that our 80s are heavy pigs and accelerating is expensive.

 

[feralyouth]

The method you used is the most inaccurate way to calculate MPG. Always start with a full tank where the stations pump click off. Reset you trip meter to zero. Drive as normal. When it's time to refill, if you can use the same pump so much the better as different pumps have different cutoff points. Fill again until the pump clicks off. Calculate MPG by dividing miles traveled by gallons pumped. Calculation accuracy can be improved with multiple fill-ups by totaling miles driven dividing by total gallons used.

Yeah I’ll try that method. Never tried to calculate mileage before cause the 88 runner and 95 LC are terrible. I’ll get back to you on the results.

 

[feralyouth]

I don't know... sounds like a serious condition, but I'm sure someone on here would take it off your hands before it causes any major headaches.

For what it's worth, I've been watching the "instant MPG" using the Torque app on my '96 and while it's not really useful as a prediction of overall mileage, it can give you a clue on how your driving is changing things. Basically, what I've learned is that our 80s are heavy pigs and accelerating is expensive.

I’ll check that app out.

 

[feralyouth]

I just did a 500 mile roundtrip and pulled 18.2 mpg. I ran it at 65 and went up to around 70 when I needed to pass. Needless to say I was not expecting that number as in mixed driving I get 12.6 as long as I am not jumping off the line at every stop.

Odd question but since you are referencing the gauge does your truck have the stock tank and not an aftermarket (larger) or second tank?

It is a stock tank. Well why I am so confused is this these aren’t just highway miles. My wife drops the kid of in town, groceries, gym etc.

 

[chairborne]

Can't speak to your experience but can say my experience has been...
...over 20mpg (~21, corrected for tire size, ~ 2.5%) on a 290kmi engine in an unloaded '93 on flat ground interstate @ 65mph 90 miles in one direction, between CO Springs and Trinidad, on 33s. Closer to 19.8mpg both ways.

THEN...on trails with full load out weight... something like 1.1GPH, roughly 10mpg.

Bottom line, it makes fuel consumption planning for a multi-day run a total bi**h. lol

Colorado has a weird gravity vortex or just no ethanol or something. I get exactly 13.6 mpg in my fat pig of an 80, but hit 16+ in western Kansas and Colorado. That’s with 35s, RTT, easily 1500 lbs over stock.