Gas Mileage Issues

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JamesAutumn

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My 225ci slant six seems to eat up more gas then what i put in it. is there any way i can tweak the mileage and get more out of my money driving it?
 
Have you figured out what the actual mpg it's getting now?

Slant six.org will have a ton of suggestions for ya. But if you don't know where you are now people won't be able to help.
 
New fuel gets really bad mileage when heated. Run a fuel return to keep it circulating . This will increase mileage.

I know an older guy who recirculates . He also takes the plug out of the spare tire tub above the tank and fills the tub with ice and a couple of beers. He swears this increases fuel mileage a lot. I myself never had tried the ice thing. but seams to makes senses. A cheap and easy large capacity cool can and beer cooler.
 
JamesAutumn said:
My 225ci slant six seems to eat up more gas then what i put in it. is there any way i can tweak the mileage and get more out of my money driving it?
Click to expand...

What year /6 and size ? are you running point's ? 1 barrel or 2 ? adjustable valve engine ?..
X 10 on the fuel getting to the carb at well over 160 degree's :glasses7:
I moved my fuel line away from the block, removed the point's and the iddie Bitty down pipe, your exhaust (if it is stock) has a 1 7/8 pipe I believe, going to a 2 1/4 exhaust will help tremendously and gain hp.
It's hot under the hood so I put a fresh cool air breather system on and it loves the 100 and lower air :glasses7:
 
i still have the plastic fuel filter on the daily driver /6 duster. made the 32 mi trip home from work other day ( 98 degrees and 1000 % humidity), shut it off looked under hood and i could see the gas in filter boilin! this is after i moved the rubber line ( from the original steel line out of pump) as far above manifold that i could! probably why it hates to start when hot, HUH! thinkin about takin one of my small early air cleaners and cuttin out the side to make fresh air cleaner. should help!? engine doesn't overheat or loose any fluilds, still getin low 20 for mileage. yea i know, get rid of plastic filter!!
 
JamesAutumn said:
My 225ci slant six seems to eat up more gas then what i put in it. is there any way i can tweak the mileage and get more out of my money driving it?
Click to expand...

This is a GOOD thing. If it ate LESS gas than you put in, you'd have to stop and drain some out every so often.

WHAT ARE you getting for mileage, and remember-------------------

you need to figure an average over several tanks......................

you need to make sure the speedo is accurate or USE A GPS............
 
i'm not sure my guages don't work right atm but i know a 17 mile trip to my cousins house one way will eat up a quarter tank and back home it'll eat the rest up 30 dollar fill ups are killin when my van will get me 40 miles to a major town and 40 miles back and only eat up a quarter the whole time.

it's a 225 ci slant six 1barrel carb all original and numbers matching with the car itself. so making it cooler under the hood should help out things a bit or no?
 
YOU CAN NOT figure gas mileage by "a quarter tank" or " a half tank." You MUST use an accurate speedo (OR A GPS) and you must average it out over several tanks.

I've bought two GPS units off CL for less than 40 bucks apiece. The cheap one I have now gives me (on one screen, at the very least)............speed, "max speed," and miles traveled, like a "trip" odometer. This is exactly what you need. Just record the trip reading at a fill up and that is your miles.
 
i'll be sure to get on it and figure out someway to get a reading on gas mileage i just know it's a money pit to make a store run. thanks for the gps suggestions i can definitely try that
 
barbee6043 said:
maybe a hole in the tank??????????????????///
Click to expand...

haha they can get 9mpg when they are angry...

what year is this and does it have a charcol canister?

here are some things i would do:

NGK ZFR5N 3459 plugs gapped to .037 with stock igniton
Standard Blue Streak Cap W/ Brass Contacts CH-410
Ignition rotor with brass contact
these ebay wires
http://www.ebay.com/itm/261045845276?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

new PCV valve and new 3/8 hose
new valve cover breather and check hose for cracking
replace air filter (wix)
 
We can't help you if you ignore the simple questions asked. 3 posts and you still didn't tell us the year. Makes a big difference. Photos would help if you don't want to read PN's to tell us what carburetor you have. Many of these cars have been modified over the years, so photos are essential.
 
A properly running slant should get 16-18 in town and 22-24 on the highway. Start with the easy stuff like a thorough tune-up.
 
Replace it with a 360. My 225 got 17, and got 17 after the swap. Plus 250HP :D

In all seriousness, go to harbor freight and buy a leak down tester and hook it up to some air, You can take it back if you don't abuse it.

See what kind of health that engine is in. Go from there.
 
+1 on start with the basics.

Also, make sure the vacuum advance is hooked up and working properly. Makes a big difference.
 
rebuild the carb, any stink is money flying out the tailpipe. Timing and valve adjustment next.
 
2 things. one easy & quick one not so much.

1. new air filter & fresh plugs. please install them straight and use 30 ft-lbs when tightening
2. switch distributor to electronic. info here: http://www.slantsix.org/articles/leanburn-article/leanburn-article.htm
you will save a ton of money by finding a '73 - '80's car or truck in a junk yard with a slant six and grabbing the ignition parts & pieces there.
 
Reading between the lines, I would say you need a major tune-up, and do it by the book. The points opening and closing is just not good enough. They need to be set. Look for vacuum leaks like bad hoses and such. Advance hose needs to be on proper port. Cap and rotor need to be in good condition and not cross firing. Plugs need to be gapped, and wires need to be in good condition and in the proper order. Clean air cleaner. Maybe run some cleaner thru the tank or re-build carb if it won't respond to tuning. Synthetic oil can help, but you won't get your money back on just mileage. There is more, but on top of all I wrote, you need to figure out if the trans is slipping, or possibly the clutch. Mileage will suffer a lot in these cases, and you won't go much farther.
 
67Dart273 said:
YOU CAN NOT figure gas mileage by "a quarter tank" or " a half tank." You MUST use an accurate speedo (OR A GPS) and you must average it out over several tanks.

I've bought two GPS units off CL for less than 40 bucks apiece. The cheap one I have now gives me (on one screen, at the very least)............speed, "max speed," and miles traveled, like a "trip" odometer. This is exactly what you need. Just record the trip reading at a fill up and that is your miles.
Click to expand...

This is a good method, but at 34 miles for $30.00 he is at about 4 miles to the gallon. No need to get any more technical when it's that poor.
 
C130 Chief said:
A properly running slant should get 16-18 in town and 22-24 on the highway. Start with the easy stuff like a thorough tune-up.
Click to expand...


Our '75 Duster got an average of 17 with a new fuel pump and a rebuilt carb...

ian.
 
Maybe the parking brake isn't releasing. Riding brake pedal? In high gear? 5.88 gear ratio?
 
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