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post #1 of (permalink) Old 09-05-2000, 12:44 AM
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2.8 mileage

i have an 85 s-10 pickup with a 2.8 v-6. it seems to be guzzling gas. i've been getting about 200 miles / tank. i think the tank is around 16 gallons. this would work out to be 12.5 mpg which is horrible especially for a small engine like a 2.8. let me know how everyone elses 2.8's are doing mileage wise and are there any reasons it should be using gas this rapidly? thanks, dennis

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post #2 of (permalink) Old 09-05-2000, 09:16 AM
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Re: 2.8 mileage

The first thing I would check would be to make sure the choke is operating properly and opening fully when the engine is warmed up.

Then I'd check the airfilter (and air tube that leads to the air cleaner housing to make sure there are no restrictions in there (and make sure the thermal door thing that pulls air from around the manifold isn't stuck in the "up" position.)), spark plugs, wires, cap & rotor to make sure they're all in good condition.

Next, I think I'd be checking things like idle mixture, to make sure it's not running rich, and ignition timing to ensure that the spark fires at the right time to get the best efficiency.

Synthetic fluids (oil, differential lube, ATF in the tranny and T case) will allegedly get you some increase in mileage (hard to say how much, and if it'd be worth it or not), I think you might find the problem in the first couple of items...

Do you drive it hard, or just nice and slow acceleration, not trying for fast? Is your transmission a manual (4 or 5 gear) or automatic? How high does it rev when you're at your normal cruising speed?

After giving mine a tuneup some mainly highway driving (55-85) got me around 20mpg (haven't calculated it yet, but will soon to be totally sure)... Do you do mainly city or highway driving? My 85 has an optional 20 gallon tank... [img]/wwwthreads_images/icons/crazy.gif[/img]

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post #3 of (permalink) Old 09-06-2000, 02:30 PM
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Re: 2.8 mileage

My '83 w/ 2.8(carb) is getting about 16MPG(city) - 20MPG(highway). I have the smaller 13 gallon tank and only go about 300 km between fillups. I don't trust my gauge below 1/4 tank any ways. The figures I got from your numbers(using the 13 gallon tank) indicate you are getting just under 16 MPG.
BTW, There were only two tanks available during these early years; the 13 or the 20 gallon

Also, It's easier to figure out your MPG based on the milage between fillups & the amout of gas used. For me, I just write down the mileage figure on the back of the recipt I get when I fill up. If you have a trip odometer just reset that every time you fill up after writing down the mileage. When I get home I just take the milage driven and divide by the number of gallons of gas. It's a bit more complicated for me because of Canada's metric system.

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post #4 of (permalink) Old 09-06-2000, 02:46 PM
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Re: 2.8 mileage

One other thing people might miss. Do you have bigger tires than stock? Even a small upgrade can affect your overall mileage, giving you worse numbers than you are calculating.

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post #5 of (permalink) Old 09-06-2000, 06:47 PM
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Re: 2.8 mileage

Also check the fuel pump. Twice in my 2.8's life time, the fuel pump has developed a intermittent leak, spraying a small stream every time the diaphram moved. Besides being bad for mileage, it is a dangerous situation. The gas mileage for my 1986 2.8L powered Jeep Cherokee is about 15 city, 20 highway. Good Luck! [img]/wwwthreads_images/icons/smile.gif[/img]

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post #6 of (permalink) Old 09-09-2000, 07:44 PM
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Re: 2.8 mileage

Rember that tire size changes the speedo which ALSO changes the oddometer! so you have to find out how many miles you REALLY went

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post #7 of (permalink) Old 09-09-2008, 09:45 PM
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2.8 V-6 mileage

I recently purchased a 1985 S-10 Blazer with about 120K miles, 2.8 V-6, automatic xmission and carburetor. It doesn't have the computer either. After replacing the EGR valve, plugs, plug wires, dist. cap & rotor and fixing vacuum leaks I get about 17 m.p.g. on the highway going a steady 60 m.p.h.
Driving some mountain roads and then highway gives about 14 -15 m.p.g. I think I got around 12 m.p.g. on mostly mountain roads with intermittent 4WD.
I replaced the stock air cleaner with a K&N, and it seems to pull hills quite a bit better, at least I can keep my speed up higher even though the transmission still downshifts a lot. My speedometer is very erratic, and way off calibration, so at first I was driving probably 45 to 50 m.p.h., thinking I was going 60. I did get 20 m.p.g. on one trip and 21 on another driving at those speeds, but I think that's quite a compromise to get 20 m.p.g. and even at night on back roads you get passed a few times. I have stock size tires. The S-10 has a bug deflector on the front a spoiler on the top of the back window to keep dust off. Could these be keeping my mileage lower, or could it be the crappy gas we get now that all has ethanol in it? I'm pretty disappointed that a small rig like this won't make 20 m.p.g. only going 60 when my wife's Jeep Cherokee with it's 4.0 l 6 cylinder will get over 20 m.p.g. cruising the freeway at 70, and it has noticeably more power and torque.
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