Its been a long time since ive posted, long story short I have had to drive my 72 250 w/360 to work around 25 miles round trip. any tips on better fuel milege. I've noticed a flat spot or hesitation on accelaration from a stop. I bought the truck about 5 years ago. I put a ignitor system to replace the points, and sealed the aux gas tank. The truck sat for two years but when i needed it I put a new battery in and she fired right up. ran kinda rough till i put new gas in but not bad. idles smooth when warmed up. The exaust smells when its cold? and idle is rough. rich? any cure for that? any way the truck runs great just a slight miss or hesitation on accelaration from a stop. any input on getting better fuel milege would be great. THANKS
72 F250 Camper Special
72 F250 Factory Highboy Custom
f26yrn04558-72 wrote:Its been a long time since ive posted, long story short I have had to drive my 72 250 w/360 to work around 25 miles round trip. any tips on better fuel milege. I've noticed a flat spot or hesitation on accelaration from a stop. I bought the truck about 5 years ago. I put a ignitor system to replace the points, and sealed the aux gas tank. The truck sat for two years but when i needed it I put a new battery in and she fired right up. ran kinda rough till i put new gas in but not bad. idles smooth when warmed up. The exaust smells when its cold? and idle is rough. rich? any cure for that? any way the truck runs great just a slight miss or hesitation on accelaration from a stop. any input on getting better fuel milege would be great. THANKS
maybe a new fuel filter, might have some jelly or rust on it. maybe add some fuel cleanr to the tank. check the plugs too.
1971 Sport Custom SWB: 360/C6 3.00
1965 Ford Falcon 4Dr: Inline 170 3sp
What you smell out the back, is it pungent. like stings your eyes? That is high HC which is most likely from a lean condition and if you have a hesitation my bet is a big vacuum leak somewhere.
Great ideas have always encounter violent opposition from mediocre minds.
I dont know how to describe the smell. just smells bad when the truck is cold. and the hesitation is from a stop or a slow roll. If I remember when I rebuilt the carb I set the fuel air screws at two and a half turns. it didnt like that so I backed them out to about four. vaccume leak is possible, I should chek the line thath goes from the manifold to the trans. should i have a noticble vaccume when I remove the vaccume advance? I pulled the line and no suction. I heard from a friend that old vehicles dont run as good cause the gas is alot different, this could be my problem too?
72 F250 Camper Special
72 F250 Factory Highboy Custom
the only reason that gas would hurt a vehicle like ours is that it is bad gas. old, has water in it. somthing mainly like that. i get mine from a local gas station and have never had a problem. as for the type i use mid when prices are up and high when prices are low. you can also use an additive with the gas.
1971 Sport Custom SWB: 360/C6 3.00
1965 Ford Falcon 4Dr: Inline 170 3sp
I thought about that but it dosent ping or nock. I live in washington state, Idont know what gas prices are in texas but they were around 4.00-5.00$$ a galan. now its down to 2.75 ish. I guess I got off topic. Thanks for the input everyone!!!! any tips on getting better gas milege? I heard you could jet the carb, do something with the distributors internals. I removed the points and put in a ignitor system, but didnt see any results. Im getting about 6-8 mpg.
72 F250 Camper Special
72 F250 Factory Highboy Custom
I'm no mechanic, but everyone tells me you should have vacuum if you pull the line off at the vacuum advance end. I'm having a prob with mine now. So good Luck.
The vacuum advance should be on ported vacuum which means there should be no vacuum signal at the dist at idle. It picks up the signal from below the throttle butterflys so they have to start opening for it to get vacuum. I use an old Motors manual for distributor specs. That will tell you how to check all that. It requires a vacuum hand pump (inexpensive) and a good timing light.
If you have the screws out 4 turns then something isn't right, highly possible its a vacuum leak somewhere.
Great ideas have always encounter violent opposition from mediocre minds.
wildcard wrote:I'm no mechanic, but everyone tells me you should have vacuum if you pull the line off at the vacuum advance end. I'm having a prob with mine now. So good Luck.
I had a similar problem with my 67. Its got a 390 in it. My solution was to give it a complete tune up including everything and it now gets 9 mpg and this is with a hi performance 390 and no hesitation at all once she is warm. BTW you said you went electronic can you give me the details. Im thinking of going that route myself. Bill
Proud owner of a '67 F100. 390 cid, Edelbrock performer, Holley 650 vs, hooker headers and a Crane cam. B&M built C-6 and 350 gears in the rear end.
no tips for ya, but when i first acquired my '76 (360 C6 4x2 Supercab), i saw 18mpg hwy and 12-14 city. it declined as engine problems developed to around 8 or 9mpg all the time. i guess bad piston rings and scarred cylinder walls will do that to a truck. im hoping the 390 im finishing now will get me back up to around what i was originally getting.
in any case, if you dont have internal engine issues, i would definitely expect that you would see better numbers than what you are currently seeing. what rear axle do you have? mine's a 3:73 ford 9", but i know ford offered a 4:10 and i think even a 4:56 back then, which would certainly have a drastic mileage effect, whether the engine was in good shape or not.
1976 Ford F-150 Supercab 4x2 w/390FE engine C6 - 76,000 miles 1995 Taurus SHO 3.0L Yamaha V6 MTX w/Quaife LSD - 75,000 miles 2002 Dodge Neon R/T 2.0L I4 MTX - 91,000 miles 1993 Dodge Ram 3500 5.9L Cummins 6x4 Flatbed MTX- 100,000 miles *SOLD*
a update on the condition of my carb troubles. I rebuilt the carb that was in it and adjusted it to spec. a few years ago. ran better but ran rough when cold and would not idle smooth with the screws at factory settings, had to run them out 4 turns. Well I went through and replaced the vaccume lines and put clamps on the hoses, thinking i had a vaccume leak. Well today I got bored a Installed the remanuf. carb I bought a few yers ago. the out side temp is in the low 30's and there is a few inches of snow on the ground. after cranking it till the carb got fuel......... It's like a new truck! no stumbling, smells, and idles smooth, even when cold. I let it warm up to temp. Idles smooth, no stumbles or hesitation. and starts right up. I am so pumped!!!!! I wonder what is wrong with the old carb? or if I goofed it up trying to rebuild it. It seemed pretty simple. Thanks for the advice everyone.
72 F250 Camper Special
72 F250 Factory Highboy Custom
Sounds like you had a vacuum leak or a bit of starvation.
I haven't checked the mileage on mine for many years but I did seem to get 12-12.5 out on the road a few years ago. That is an F250 crew cab with a 390 4 speed 3.73 gear (a very tired 390).
Great ideas have always encounter violent opposition from mediocre minds.
but when i needed it I put a new battery in and she fired right up. ran kinda rough till i put new gas in but not bad. idles smooth when warmed up. The exaust smells when its cold? and idle is rough. rich? any cure for that? any way the truck runs great just a slight miss or hesitation on accelaration from a stop. any input on getting better fuel milege would be great. THANKS 
I wonder what is wrong with the old carb? or if I goofed it up trying to rebuild it. It seemed pretty simple. Thanks for the advice everyone.