Very Low MPG? Burning Oil?
02-09-2010, 02:03 PM
#1
JK Enthusiast
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Very Low MPG? Burning Oil?
Ok so I have an 07 Unlimited w/ 35x12. Trail Grapplers. I am also running the superchips 93 performance tune. I am averaging 10.4 mpg!!! When I first got the superchips I was at like 13-14mpg I calibrated my speedo it seems like its dead on... Why am I getting such low #'s? Then I went to change my oil the other day and it was really low!!
I thought I had a whole in my oil pan!! I was only at around 3500-3700 miles since my last change. I use Royal Purple with their oil filter... any suggestions? besides keep my foot out of it... i tried... even tried turning O/D off. Is the higher Octane have anything to do with the oil burning? I know JK's burn a little but mine was more than the norm. Thanks guys
I thought I had a whole in my oil pan!! I was only at around 3500-3700 miles since my last change. I use Royal Purple with their oil filter... any suggestions? besides keep my foot out of it... i tried... even tried turning O/D off. Is the higher Octane have anything to do with the oil burning? I know JK's burn a little but mine was more than the norm. Thanks guys
02-09-2010, 08:51 PM
#2
JK Enthusiast
get under there and see if a rear seal is leaking. A leak doesn't always end up on the ground, it can fall onto another part of the undercarriage and u might not notice it.
02-09-2010, 09:33 PM
#3
JK Freak
what was the actual level, "really low" can be interpreted many ways. some would say 1 qrt is really low others dont consider really low untill it is not on the dipstick.
i could list u 50 reasons why u have low mpg.
what is your total mileage for the jeep?
are u using the jeep computer or actual math to determine mpg?
how many tanks of gas has the mpg been around 10? (just a couple tanks does not tell u much)
what are ur tire psi's and are they close to recomended psi?
how much oil did u drain out?
with the 93 tune, do u run 93 or lower? (some tunes wth other programmrs, u tune for 93 but can run 87)
what do you consider being the "norm" for oil usage or what have u read or being told?
have u pulled your spark plugs to check for excess oil on the tip?
yo could have leaks that dont drip on ground, you need to visualy inspect everything. i found a small leak on my engine, typically u cannot see where it was leaking untill i had my wheel well inserts out.
maybe u should return back to the normal fuel tuning and see what u get after that
i could list u 50 reasons why u have low mpg.
what is your total mileage for the jeep?
are u using the jeep computer or actual math to determine mpg?
how many tanks of gas has the mpg been around 10? (just a couple tanks does not tell u much)
what are ur tire psi's and are they close to recomended psi?
how much oil did u drain out?
with the 93 tune, do u run 93 or lower? (some tunes wth other programmrs, u tune for 93 but can run 87)
what do you consider being the "norm" for oil usage or what have u read or being told?
have u pulled your spark plugs to check for excess oil on the tip?
yo could have leaks that dont drip on ground, you need to visualy inspect everything. i found a small leak on my engine, typically u cannot see where it was leaking untill i had my wheel well inserts out.
maybe u should return back to the normal fuel tuning and see what u get after that
02-10-2010, 03:59 AM
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I know its not the same engine but i had a problem like this in my Durango. The intake gasket would develop a leak at the engine block. It would suck the oil through into the intake and burn it with the air/fuel mixture. Not enough to smoke, but would be three quarts low in a couple thousand miles. The drop in vacuum would cause the engine to lose performance and mileage. It was a subtle change that you would not notice right away. I think when I traded it I was on my third gasket. CM
02-10-2010, 07:23 AM
#5
JK Super Freak
If you have more power with the Superchips, and you are enjoying using it, you mileage may suck. It is not hard to make even a stock Jeep get 10 mph if you hammer it alot. Still, that is worse mileage than I get.
You should not be using oil.
Check your coolant and make sure it is not slimey with oil, which could indicate a bad gasket or something warped or cracked.
Run your finger around the inside of the tail pipe, should be nothing but soot, no oiley film. If there is (and sometimes even if there is not), your burning oil, and that could also be gasket/warpage/cracked something. Could also be piston/ring or valve train problem. Checking the spark plugs can also show you any cylinder burning oil. You may need to check compression.
Take a bright light and crawl around under the Jeep. There was a TSB for the 07's for a porous timing chain cover that leaks oil. High speed winds from driving can spread the oil a long ways from where the leak is. If you see oil, clean it all up well and then start checking often for the source.
My 07 came with a lifetime drive train warranty (which I have kinda voided)
, did yours? If you are under warranty, reflash back to stock and try to get the dealer to fix it. I have found it is better to know what is wrong with it before taking it for dealer repair so they can't run you around.
You should not be using oil.
Check your coolant and make sure it is not slimey with oil, which could indicate a bad gasket or something warped or cracked.
Run your finger around the inside of the tail pipe, should be nothing but soot, no oiley film. If there is (and sometimes even if there is not), your burning oil, and that could also be gasket/warpage/cracked something. Could also be piston/ring or valve train problem. Checking the spark plugs can also show you any cylinder burning oil. You may need to check compression.
Take a bright light and crawl around under the Jeep. There was a TSB for the 07's for a porous timing chain cover that leaks oil. High speed winds from driving can spread the oil a long ways from where the leak is. If you see oil, clean it all up well and then start checking often for the source.
My 07 came with a lifetime drive train warranty (which I have kinda voided)
, did yours? If you are under warranty, reflash back to stock and try to get the dealer to fix it. I have found it is better to know what is wrong with it before taking it for dealer repair so they can't run you around.
Last edited by Yankee; 02-10-2010 at 07:29 AM.
02-10-2010, 10:13 AM
#6
JK Junkie
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This totally sounds like a PCV valve issue.
If the PCV valve is clogged you will evacuate crankcase pressure through the breather and into the air inlet tube. This will cause a loss of oil, at most perhaps a quart per 1,000 miles. This will also effect performance as you are burning a slight amount of oil with your fuel.
That's where I would start if you don't see any tell tale signs of an oil leak.
If the PCV valve is clogged you will evacuate crankcase pressure through the breather and into the air inlet tube. This will cause a loss of oil, at most perhaps a quart per 1,000 miles. This will also effect performance as you are burning a slight amount of oil with your fuel.
That's where I would start if you don't see any tell tale signs of an oil leak.
02-10-2010, 03:40 PM
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what was the actual level, "really low" can be interpreted many ways. some would say 1 qrt is really low others dont consider really low untill it is not on the dipstick.
i could list u 50 reasons why u have low mpg.
what is your total mileage for the jeep?
are u using the jeep computer or actual math to determine mpg?
how many tanks of gas has the mpg been around 10? (just a couple tanks does not tell u much)
what are ur tire psi's and are they close to recomended psi?
how much oil did u drain out?
with the 93 tune, do u run 93 or lower? (some tunes wth other programmrs, u tune for 93 but can run 87)
what do you consider being the "norm" for oil usage or what have u read or being told?
have u pulled your spark plugs to check for excess oil on the tip?
yo could have leaks that dont drip on ground, you need to visualy inspect everything. i found a small leak on my engine, typically u cannot see where it was leaking untill i had my wheel well inserts out.
maybe u should return back to the normal fuel tuning and see what u get after that
i could list u 50 reasons why u have low mpg.
what is your total mileage for the jeep?
are u using the jeep computer or actual math to determine mpg?
how many tanks of gas has the mpg been around 10? (just a couple tanks does not tell u much)
what are ur tire psi's and are they close to recomended psi?
how much oil did u drain out?
with the 93 tune, do u run 93 or lower? (some tunes wth other programmrs, u tune for 93 but can run 87)
what do you consider being the "norm" for oil usage or what have u read or being told?
have u pulled your spark plugs to check for excess oil on the tip?
yo could have leaks that dont drip on ground, you need to visualy inspect everything. i found a small leak on my engine, typically u cannot see where it was leaking untill i had my wheel well inserts out.
maybe u should return back to the normal fuel tuning and see what u get after that
When i say really low the dipstick had about 1/8-3/16" on it... so it was really low...
I am using the computer for the calcs...
I've gone through about 8-10 tanks of gas
I am running my tires at about 28Psi and running 93 octane
I've searched oil burning on here and it seems like everyone is saying about 1 quart between oil changes is normal. well at least thats what the dealer told them.
Have not checked the plugs maybe I will just replace them with the net oil change/tune up...
I do have an extended warranty untill 70k just wanted to know if anyone else has the same issues... I don't want to pay the $100 deductible to find out the dealer is going to say its normal. ya know?
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02-10-2010, 06:38 PM
#9
JK Freak
Total mileage- 44,000~
When i say really low the dipstick had about 1/8-3/16" on it... so it was really low...
I am using the computer for the calcs...
I've gone through about 8-10 tanks of gas
I am running my tires at about 28Psi and running 93 octane
I've searched oil burning on here and it seems like everyone is saying about 1 quart between oil changes is normal. well at least thats what the dealer told them.
Have not checked the plugs maybe I will just replace them with the net oil change/tune up...
I do have an extended warranty untill 70k just wanted to know if anyone else has the same issues... I don't want to pay the $100 deductible to find out the dealer is going to say its normal. ya know?
When i say really low the dipstick had about 1/8-3/16" on it... so it was really low...
I am using the computer for the calcs...
I've gone through about 8-10 tanks of gas
I am running my tires at about 28Psi and running 93 octane
I've searched oil burning on here and it seems like everyone is saying about 1 quart between oil changes is normal. well at least thats what the dealer told them.
Have not checked the plugs maybe I will just replace them with the net oil change/tune up...
I do have an extended warranty untill 70k just wanted to know if anyone else has the same issues... I don't want to pay the $100 deductible to find out the dealer is going to say its normal. ya know?
the plugs is a a way to check if oil is blowing by the rings on the pistons. usualy u would have 1 or 2 plugs that were more oily than the others. if one plug is very oily , then its possible u have bad rings.
depending on your tires, 28 psi is kinda low. i went from 25psi to 35 psi and my mileage improved from 14 to 16 mpg.also the cold temps will wreek havok on mpg.
i used hyperteck programmer with the 93 tune and i think my mpg did go down, then changed back to 87. u might want to experiment if your pack allows it. tune for 93 but run 87 only if ur programer says u can do that.
i was one of the ones on this forum debating the normal usage for oil on the jk. i wont go there on here. unfortunately, chysler will probably tell you that 1 qrt of oil per 1,000 miles is ok, acceptable, or normal. if your jeep is under that warranty, and u dont want to pay that deductable, i would try these tips first and then go from there.
if they tell you that using 3 qrts of oil between oil changes of 3,000 miles, keep pushing the issue, as you truly could have an internal problem or like someone else mention, the PCV valve is bad.
02-10-2010, 08:18 PM
#10
JK Freak
from the low mark and the full mark on the dipstick is only 1 qrt low.
the only way to tell what the reading would be below that, is to drain the oil and see how much oil drains out. looks like people are using 5.5 to 6 qrts to refill. or when u refill, check the dipstick at each qrt added and see where the marks are, then u can figure out how low it actually is below the mark. it may turn out tip of dipstick could equal 1 qrt low below the low mark which would equal 2 qrts low total from full mark.
the only way to tell what the reading would be below that, is to drain the oil and see how much oil drains out. looks like people are using 5.5 to 6 qrts to refill. or when u refill, check the dipstick at each qrt added and see where the marks are, then u can figure out how low it actually is below the mark. it may turn out tip of dipstick could equal 1 qrt low below the low mark which would equal 2 qrts low total from full mark.