Gas Mileage

[Wagoneer622]

My Wagoneer scared me last night, I think something is wrong like a cloged fuel filter or bad fuel pump. Here is what happened, Last night I had to make a 80 mile trip, most of the time was spent at 65-75mph range. I stop at the gas station because the gas gauge didn't even read 3/4. I thought, it's screwed up. Fill it up, it only takes 3 Gallons of gas. That is approx. 27 miles per gallon. I'm thinking NO WAY!!, thats impossible. I usually get 11-13 driving around town.

However, noting leads to these being bad, the truck purs like a kitten and has plenty of power. Is it possible to get this out of a 360 with 133,000 miles on it completely stock. I think the fuel pump is good because there is no gas in the oil and it pumps to the carb with plenty of pressure and the fuel is clean. I think I am going crazy, it has really got me worried getting that good a milage out of it. Please let me know what you think.


Chris
83 Wagoneer Ltd.(360/727/229)

[Freezer]

What do I think? I want your JEEP ;)

[irbob]

What do I think....your crazy. :D No just kidding. I think the gas pump stopped b4 the tank was completely filled up. An gas bubble in the tanks belly. Just a thought.

[LRRH]

sounds like the filler neck for the gas tank. they really suck, and this happens a lot. sometimes i can barely fill it up because air keeps getting caught. there was a technical fix somewhere...

http://www.ifsja.org/tech/fuel/jerrycanmod.shtml

there.

[Lindel]

Chris, next time you fill up, try it with the handle of the pump nozzle pointing at 1:00, or 11:00 (nearly straight up), and see if you can
1- fill it all the way, and 2- fill it more quickly.

That's how I have to fill mine, but I can usually pump about 15 gallons into in 3, or 4 minutes, instead of 10, or 15 minutes.

Either that, or just stick the nozzle in enough that it will stay on it's own, and set on the lowest setting. That way, you can clean windows, check oil, etc, while it's filling up.

[UnkleMunky]

Since it only took 3 gallons, AND it was only one fill, I'd chock it up as something was amiss. Next time you fill up, you might calc it out at 5mpg. If you regularly are getting 11-12, and that's norm for these rigs, that's more likely your normal, and either it did fill up oddly(not completely) or some other factors were at play. It'd be wonderful if that were regular mpg for ya, but I'd gather it's an exception.

I'd gotten 19.9 a couple months ago with my 78 J10(258/4 speed), and was excited about that, and posted on here about it, but my "normal" is in the 15-18 mpg range, so 19.9 wasn't exacly "that" out of whack. I still have lots of tuneup work to do on this truck, and do hope to pull a regular 20 mpg out of it, but I can't complain at the 15-18mpg on it....that's all lots of newer trucks get!

I'd recommend 2 things:
1) keep track of your fillups/gasups on a regular basis. I keep a logbook in the Jeep(and every vehicle actually) and try to fill up EVERY time I get gas. This way, I can keep track and see if things are out of norm. This will help you see any oddities or where your patterns really might be!
2) check your odometer/speedometer(but mainly odom). I do this on the freeway myself. Go by the milemarkers. Clock it to see if 1 mile on the road = 1.0 miles on your odom. If not, do the math to figure where you might be at really. Also, I check the speedo when I do this too, go 60mph on the highway/freeway(where you can go at least that or more), and do the same for milemarkers. 1.0 miles on the road at 60mpg should take you "exactly" 60 seconds or 1 minute. Check this a few times over a few miles and see how it turns out. If you're right on, then you know so. If not, you might need to do some math for your calculations to see if all your mpg figures are on target or not.

Anyway.....wish you could get that regularly with a Wag. I know I always had trouble with my '77 Cherry on fillups....always had to hold it while filling, so as others mentioned, that could be an issue at a particular station with a particular pump that may fill differently than others. Just have to see how your average is overall and see how things look there! smile.gif

Take care....

[Wagoneer622]

Well Guys,
I changed the fuel filter tody and it was completely clogged. Change the filter take it out for a ride. I fill it up at the gas station and no problems. I am back to getting my usual 11-12mpg. Also, the motor is running much better. I find it good practice to always check my gas milage on fill ups, I keep a log in my glove compartment. So far I know everytime I have filled up since last April. I can see the results of changing stuff.

Onto a new thing, I am on my way to Point Pleasante tonight and my brake pedal goes to the floor. Get out of the truck, low and behold the master cylinder is leaking, I guess I know what i am doing after school tomorrow. At least I can drive my father's pristine 87 Grand Wagoneer, and not something else. Thanks for all of the suggestions everybody(even turning the pump around didn't work on Sunady night) I should be fine as soon as I change the master cylinder. Have a good evening.


Chris
83 Wagoneer Ltd.(360/727/229)

[UnkleMunky]

Yeh, now that you have an unclogged fuel filter, going ahead isn't a question, but you definitely want to be able to STOP! :D

I agree on the log book, etc. routine as I noted. I know not everyone does it and is why I recommended, but glad you're doing that! I like how I can keep tabs on things too that way.

Take care....