Gas Mileage Tanked Bad

[redwolf624]

since my father is no help to me anymore cause he's too lazy to help me figure it out i'm relyin on yall, when i first dropped the 93 sonoma 2.8 in my MJ and after adjustin the valves, timin and carb i had wonderful gas mileage, i'd get 17-19 but now i'm gettin like 10-13, i'll be fillin up my tank at the end of every week, i don't know where to start, what could be causin my gas mileage to tank like that, i know i don't have the best carb in the world bein that it's a rotchester carb but even before i rebuilt it i was gettin great mileage, any ideas?

 

Redwolf

[Eagle]

If you were getting good mileage before rebuilding the carb and poor mileage after rebuilding the carb, I'd guess that something in the carburetor got messed up during the rebuild.

[Eagle]

since my father is no help to me anymore cause he's too lazy to help me figure it out i'm relyin on yall, when i first dropped the 93 sonoma 2.8 in my MJ and after adjustin the valves, timin and carb i had wonderful gas mileage, i'd get 17-19 but now i'm gettin like 10-13, i'll be fillin up my tank at the end of every week, i don't know where to start, what could be causin my gas mileage to tank like that, i know i don't have the best carb in the world bein that it's a rotchester carb but even before i rebuilt it i was gettin great mileage, any ideas?

 

Redwolf

I'm sorry, but after this post I just have to say something. Is your keyboard defective? Doesn't it have a 'G' key? The following words ALL end in the letter 'g'. Is it so difficult to just type the last letter?

 

relyin

adjustin

timin

gettin

fillin

causin

bein

gettin

[redwolf624]

If you were getting good mileage before rebuilding the carb and poor mileage after rebuilding the carb, I'd guess that something in the carburetor got messed up during the rebuild.

 

when i did rebuild the carb i had better mileage but now after almost 8 months of it runnin and a rebuilt carb the gas mileage tanked

 

since my father is no help to me anymore cause he's too lazy to help me figure it out i'm relyin on yall, when i first dropped the 93 sonoma 2.8 in my MJ and after adjustin the valves, timin and carb i had wonderful gas mileage, i'd get 17-19 but now i'm gettin like 10-13, i'll be fillin up my tank at the end of every week, i don't know where to start, what could be causin my gas mileage to tank like that, i know i don't have the best carb in the world bein that it's a rotchester carb but even before i rebuilt it i was gettin great mileage, any ideas?

 

Redwolf

I'm sorry, but after this post I just have to say something. Is your keyboard defective? Doesn't it have a 'G' key? The following words ALL end in the letter 'g'. Is it so difficult to just type the last letter?

 

relyin

adjustin

timin

gettin

fillin

causin

bein

gettin

 

not a defective keyboard i just don't add G to the end of my words that use ING, just how i am,

 

Redwolf

[HOrnbrod]

when i did rebuild the carb i had better mileage but now after almost 8 months of it runnin and a rebuilt carb the gas mileage tanked............

:huh???:  Eight months?? You were askin about carb kits just last February.  :hmm:

 

http://comancheclub.com/topic/42121-running-rough-doesnt-wanna-start-but-timing-is-dead-on/?hl=rebuild+kit&do=findComment&comment=427512

[redwolf624]

 

when i did rebuild the carb i had better mileage but now after almost 8 months of it runnin and a rebuilt carb the gas mileage tanked............

:huh???:  Eight months?? You were askin about carb kits just last February.  :hmm:

 

http://comancheclub.com/topic/42121-running-rough-doesnt-wanna-start-but-timing-is-dead-on/?hl=rebuild+kit&do=findComment&comment=427512

 

yeah but i never rebuilt it, that last time i rebuilt is it was in may or june,

 

Redwolf

[gogmorgo]

not a defective keyboard i just don't add G to the end of my words that use ING, just how i am,

 

It may be the way you are, and I really don't want to be a fool about this, but the reason English was standardized was to improve clarity of communication. Many of your posts are not clear. It's a struggle, I know, but it would really help help us to help you if your written grammar was a little more standard.

The "g" isn't so much a clarity issue as a few other things you do regularly. From your last post "that last time i rebuilt is it was in may" is far from a standard, although more than likely a typo that a simple rereading could have caught. When I post, I reread before I hit "post" and often afterwards, and I'll edit right away if I catch a mistake.

A tips that would improve the clarity of your posts substantially would be to avoid run-on sentences. Keep your sentences basic. For example, the sentence Hornbrod quoted:

when i did rebuild the carb i had better mileage but now after almost 8 months of it runnin and a rebuilt carb the gas mileage tanked

Would be much clearer if you had written it like this:

 

I rebuilt the carb almost eight months ago and had better mileage. Now the mileage tanked.

 

This also brings up another issue, which would be helpful in solving your current issue. So I was able to understand from that sentence that eight months ago your carburetor was rebuilt and it was good. But the did the "eight months of it runnin" come before a rebuilt carb was installed (just now) or are we still talking about the same rebuilding that happened eight months ago?

 

Again, I don't want to be a fool. You seem to be a decent person in need of help, and I'd like to help you. I don't really have the technical expertise to help you with your exact issue, but there are people on this forum who can. Unfortunately, though, they find it frustrating that you can't communicate clearly what issue you're having.

 

For starters, be open with all information.

Has anything else changed besides the poor fuel economy? You were looking at adjusting air/fuel ratios and rebuild kits. Did you end up doing anything at all to your carb, or did you just start getting terrible mpg?

[redwolf624]

 

not a defective keyboard i just don't add G to the end of my words that use ING, just how i am,

 

It may be the way you are, and I really don't want to be a fool about this, but the reason English was standardized was to improve clarity of communication. Many of your posts are not clear. It's a struggle, I know, but it would really help help us to help you if your written grammar was a little more standard.

The "g" isn't so much a clarity issue as a few other things you do regularly. From your last post "that last time i rebuilt is it was in may" is far from a standard, although more than likely a typo that a simple rereading could have caught. When I post, I reread before I hit "post" and often afterwards, and I'll edit right away if I catch a mistake.

A tips that would improve the clarity of your posts substantially would be to avoid run-on sentences. Keep your sentences basic. For example, the sentence Hornbrod quoted:

when i did rebuild the carb i had better mileage but now after almost 8 months of it runnin and a rebuilt carb the gas mileage tanked

Would be much clearer if you had written it like this:

 

I rebuilt the carb almost eight months ago and had better mileage. Now the mileage tanked.

 

This also brings up another issue, which would be helpful in solving your current issue. So I was able to understand from that sentence that eight months ago your carburetor was rebuilt and it was good. But the did the "eight months of it runnin" come before a rebuilt carb was installed (just now) or are we still talking about the same rebuilding that happened eight months ago?

 

Again, I don't want to be a fool. You seem to be a decent person in need of help, and I'd like to help you. I don't really have the technical expertise to help you with your exact issue, but there are people on this forum who can. Unfortunately, though, they find it frustrating that you can't communicate clearly what issue you're having.

 

For starters, be open with all information.

Has anything else changed besides the poor fuel economy? You were looking at adjusting air/fuel ratios and rebuild kits. Did you end up doing anything at all to your carb, or did you just start getting terrible mpg?

 

first off sorry if what i post seems to be hard to understand, i try my best to make it easily understandable. second i had rebuilt the carb back in either may or june, it was shortly after i got my MJ running and passed state inspection, here is what i have tried to do to fix the bad milage; gapping spark plugs, chaging spark plug wires (which were badly needed) adjusting the fuel/air on the carb, carb cleaner (after that the engine ran smoother but mileage went down even more) the only thing i have not tinkered with is the manual choke and rebuilding the carb again, i'm just wondering if i need to do a tune up on my MJ, the last tune up done was back in may or june of last year,

 

Redwolf

[gogmorgo]

Any chance you could put your air/fuel back to what it was before?

If I'd have to hazard a guess, the lack of smooth running would have been due to the bad spark plug wires, and not an issue with air/fuel. At any rate, that ratio was working pretty well, and your current air/fuel ratio doesn't seem to be.

 

What does a tune up consist of? In my mind, that's plugs, wires, cap, rotor, filters, and a general inspection of things.

[redwolf624]

Any chance you could put your air/fuel back to what it was before?

If I'd have to hazard a guess, the lack of smooth running would have been due to the bad spark plug wires, and not an issue with air/fuel. At any rate, that ratio was working pretty well, and your current air/fuel ratio doesn't seem to be.

 

What does a tune up consist of? In my mind, that's plugs, wires, cap, rotor, filters, and a general inspection of things.

i don't know if i have the fuel/air ratio back to what is was, i have it where if i hook up a vaccum gauge when i start dropping vaccum i turn it back to where it goes up and once it stops goin up i stop. and a tune up (what i've grown up knowing it to be) is spark plugs, wires (depending on how new and if ya wanna get em) cap, rotor, oil change, air filter and a gerneral inspection of brakes, belts and other goodies,

 

Redwolf

[92tanMJ]

 

since my father is no help to me anymore cause he's too lazy to help me figure it out i'm relyin on yall, when i first dropped the 93 sonoma 2.8 in my MJ and after adjustin the valves, timin and carb i had wonderful gas mileage, i'd get 17-19 but now i'm gettin like 10-13, i'll be fillin up my tank at the end of every week, i don't know where to start, what could be causin my gas mileage to tank like that, i know i don't have the best carb in the world bein that it's a rotchester carb but even before i rebuilt it i was gettin great mileage, any ideas?

 

Redwolf

I'm sorry, but after this post I just have to say something. Is your keyboard defective? Doesn't it have a 'G' key? The following words ALL end in the letter 'g'. Is it so difficult to just type the last letter?

 

relyin

adjustin

timin

gettin

fillin

causin

bein

gettin

 

 

Since my father is no longer any help to me because he is too lazy to help me figure out what is wrong with my truck, and I am too lazy to go read books or other sources of information, or google it or figure it out  myself- I am going to rely on you all for everything. When I first put the 93 Sonoma 2.8 into my MJ- after adjusting the valves, timing, and the carb(??). I had wonderful gas mileage; I got 17-19 mpg. But now I am getting about 10-13. I normally fill up my tank at the end of every week and I don't know where to start- what could be causing my gas mileage to tank like that? I know I don't have the best carb in the world, being that it's a Rochester carb, but even before I rebuilt it I was getting decent mileage. Any ideas?

 

Thanks,

Redwolf

 

 

 

:thumbsup:

[Blue88Comanche]

Grammar Nazis everywhere!

 

 

 

 

 

 

[Eagle]

Grammar Nazis everywhere!

It's a tough job, but somebody's gotta do it.

 

The thing is, we're all busy and we all have too many things going on, and it takes three or four times longer to try to decipher a post that's written in poor English with little or no punctuation as it does to read something that's in "standard" English. I realize I'm an olde pharte and a curmudgeon but, after awhile, I just stop trying and I won't read such posts any more. If one of them happens to be one to which I know the answer -- who loses?

 

Not me.

[redwolf624]

can we all stop being grammer nazis and help answear the question of what could be causing bad fuel mileage,

 

Redwolf

[92tanMJ]

That spolier thing is awesome Blue!! But most of the things I fixed, were just making it sound uninbredish. And I agree 100% with Eagle on this one. But I don't know maybe it just the way he was talking bad about his dad or maybe it is the fact that he is being just as lazy by asking us instead of figuring it out himself that rubbed me the wrong way. But either here nor there, no one can help him if no one understands what he's asking...

[redwolf624]

That spolier thing is awesome Blue!! But most of the things I fixed, were just making it sound uninbredish. And I agree 100% with Eagle on this one. But I don't know maybe it just the way he was talking bad about his dad or maybe it is the fact that he is being just as lazy by asking us instead of figuring it out himself that rubbed me the wrong way. But either here nor there, no one can help him if no one understands what he's asking...

i've tried to figure out what's causing my bad mileage, i've played with the spark plugs by gapping them at 45 (like they should be for a normal 2.8), i've tried 35 and 40 (which is the best right now). I've adjusted the valves and i've played with the carbs fuel/air mixure, nothing is helping me get better mileage, i even changed the way i shift, thinking i was shifting too early or too late. I ran out of ideas and can't think of what else could cause such bad mileage,

 

Redwolf

[yxmj]

 

i've tried to figure out what's causing my bad mileage, i've played with the spark plugs by gapping them at 45 (like they should be for a normal 2.8), i've tried 35 and 40 (which is the best right now). I've adjusted the valves and i've played with the carbs fuel/air mixure, nothing is helping me get better mileage, i even changed the way i shift, thinking i was shifting too early or too late. I ran out of ideas and can't think of what else could cause such bad mileage,

 

Redwolf

 

Please decribe the process you used to do this?

[AMCJeepMJ]

I have to ask the obvious questions since I did not see them already in the thread. Apologies if I missed them.

 

-Are the tires aired up?

-Hauling a bunch of stuff in the bed?

-Filters not blocked up [fuel, air]?

-Fluids at their proper levels? [gearbox, diff, engine oil, etc.]?

-Exhaust plugged [bad cat, etc.]?

 

 

 

 

[redwolf624]

 

i've tried to figure out what's causing my bad mileage, i've played with the spark plugs by gapping them at 45 (like they should be for a normal 2.8), i've tried 35 and 40 (which is the best right now). I've adjusted the valves and i've played with the carbs fuel/air mixure, nothing is helping me get better mileage, i even changed the way i shift, thinking i was shifting too early or too late. I ran out of ideas and can't think of what else could cause such bad mileage,

 

Redwolf

 

Please decribe the process you used to do this?

 

 

this is what i followed when i adjusted my valves:

 

1. Disconnect the cable from the negative batter terminal.

2. if the rocker arm covers are still on the engine, refer to section 4 and remove them (section 4 just tells ya what to take off to take the covers off)

3. if the valve train components have been serviced just prior to this procedure, make sure that the components are completely reassembled.

4.rotate the crankshaft untill the nuber one piston is at top dead center (TDC) on the compression stroke. To make sure you do not mic up the TDC positions of the number one and four pistions, place your fingers on the number one rocker arms as the timing marks line up at the crankshaft pulley. If the rocker arms are not moving, the number one pistion is not at TDC. If they move as the timing marks line up, the number four pistion is at TDC.

5. back off the rocker arm nut untill play is felt at the pushrod, then turn it back untill all play is removed. This can be determinded by rotating the pushrod white tighting the nut. Just when drag is felt at the pushrod, all lash has been removed. Now turn the nut an additional 1 1/2 turns.

6. Adjust the number one, five, and six cylinder intake valves and the number one, two and three crankshaft valve in this position, using the method just described.

7. Rotate the crankshaft untill the number four pistion is at TDC on the compression stroke and adjust the number two, three, and four cylinder intake valves and the number four five and six cylinder exhaust valves,

8. install rocker arm covers

I have to ask the obvious questions since I did not see them already in the thread. Apologies if I missed them.

 

-Are the tires aired up?

-Hauling a bunch of stuff in the bed?

-Filters not blocked up [fuel, air]?

-Fluids at their proper levels? [gearbox, diff, engine oil, etc.]?

-Exhaust plugged [bad cat, etc.]?

tires are at 35PSI, i'm not haulin anything but my hi left jack and my spare tire, air filter is clean and i don't know bout the fuel filter, all fluid are good, and i don't know if i got a bad cat or not,

 

Redwolf

[redwolf624]

so i adjusted the valves again today like the haynes manual says and i lost a quarter tank of gas within 1 minute, adjusted the valves again but to a 1/2 a turn instead of 1 1/2 turn and it's back too where it was, i think wednesday when i'm off again and when i have light i'll add another 1/2 turn and that should put me right or should i got in the middle of 1 1/2 turn?

 

Redwolf

[yxmj]

I am not a professional motor builder......I have had my hands on my share of

 AMC inline 6's.....how you lost 25% of your fuel in one minute......WoW......i do not know what you are doing but the nut that holds the lifter one needs to be

@ 19 lbs.....and even if it was off by a pound.......I do not understand how it would affect your fuel consumption.............are you confusing adjusting the "valves" that let fuel in the motor and exhaust gassesout to..... adjusting your carb??????.....

[redwolf624]

I am not a professional motor builder......I have had my hands on my share of

 AMC inline 6's.....how you lost 25% of your fuel in one minute......WoW......i do not know what you are doing but the nut that holds the lifter one needs to be

@ 19 lbs.....and even if it was off by a pound.......I do not understand how it would affect your fuel consumption.............are you confusing adjusting the "valves" that let fuel in the motor and exhaust gassesout to..... adjusting your carb??????.....

i would adjust the carb but it'd be pointless with my valves still clattering. i don't know what has gone wrong with my MJ but every time i do somethin to it now it messes my truck up worse, i'm smelling raw gasoline from the exhaust after the engine heats up, it hesitates to go, it acts like it wants to die as if the carb is starving it of fuel, i know i gotta mess with the valves again but being that i'm messing with those should i also mess with the carb's fuel/air mixure after adjusting valves? another thing, how do i check the vaccum advance, because i remember reading somewhere that it could cause valves to clatter if it's bad, also what do you mean that the nut that holds the lifter one needs to be at 19lbs; is that torqued at 19lbs?

 

Redwolf

[Eagle]

My brother's buddy the stock car racer always adjusted Chevy valves with the engine running. Back off until the rocker clatters, then tighten until it stops making "I'm falling apart" noises.

 

It's messy -- there will be oil squirting around.

[redwolf624]

My brother's buddy the stock car racer always adjusted Chevy valves with the engine running. Back off until the rocker clatters, then tighten until it stops making "I'm falling apart" noises.It's messy -- there will be oil squirting around.

Yeah i know it'll be messy, ive never adjusted valves with the engine running right, i have always made it worse than if i have done it dead ice cold. What i didnt understand though is when i went 1 1/2 of a turn yesterday it was knockin hard and sounded like all the valves were open,

 

Redwolf

[Eagle]

Check your pushrods -- see if any of them got bent.