Running Rich

[Matthew1785]

I think i might be running rich. every time i fill up i always reset my mile logger and i've been noticing im only getting 15 MPG, the only mod i've installed is a K&N filter with the stock hose still attached. what would cause me to run so rich and is this normal. I'm not romping on the engine "well maybe once in a blue moon" anyone got any ideas. i was searching through the fourms and it looks like replacing the spark plugs would somewhat solve the problem.. but any input would be awesome thanks!

 

[Matthew1785]

also i've popped no CEL's so i dont think it could be a bad O2 Sensor

 

[Matthew1785]

anyone got an idea?

 

[Demoniam]

Time for a general tune-up???...plugs/wires/airfilter/fuel filter?/pcv valve/Sea Foam/EGR cleaning...

 

[Captain KRM P5]

how many miles are on her? could be tune up time...

 

[Thekid760]

I see you have an auto, that contributes to bad MPG, but not that bad.
Try a complete tune up, and let us know how it turns out.

I only get 23-25 on avg with my car, & I thought that sucked.

 

[Tasty]

15 mpg?! Wow, something is NOT right. I would try what others have suggested. Plugs, dump some Sea Foam in the next tank of gas. No CELs though...strange. That is really horrid mileage for this car, even an auto. I have a manual and get a little over 31 on the highway.

 

[Flash5]

Check the air in your tires, that could be contributing as well.

 

[redpr5]

yea def check tires. i was averaging 22mph on the highway cuz my front tires were both at 19psi when they shouldve been at 35

i too have an auto, but i average about 27-28mpg a fill up (combined city and some highway driving)

 

[gimpo2]

15mpg? you're only getting 200 miles a tank? thats extremely bad. i had that gas mileage with a turbo and auto

 

[fransua11]

I have recently bought a MP5 and I am getting around 15 mpg as well, sometimes even 13-14. Every time I calculate my consumption I had a headache.... I have been to a garage but could not find anything that would give me a clue what is it. I put some Tune-Up liquid in the engine but nothing helps. I do not think that this something to do with the compression either. As the mechanic told me if the compression would be less than normal it would use less gas not more. I am thinking now to trade it with another one in the spring.

 

[BKJT05]

15mpg? you're only getting 200 miles a tank? thats extremely bad. i had that gas mileage with a turbo and auto

sorry to thread jack, but do turbo's cause you to loose that much mpg??? I get a avg 28-30 mpg now, im going turbo this next spring, will my mpg drop that bad or did you just have something wrong etc??? THANKS

 

[Matthew1785]

its ok i figured it out. spoke with moonman8 today we estimated i'm getting at least 22-23MPG. most of my driving is suburb driving. but to answer the questions. its got 33200 miles on it spark plugs have not been replaced, they will however be getting replaced next saturday. tires are fine.

 

[redpr5]

burned out spark plugs ftl

 

[bazooka joe]

i've got a turbo'd auto and i just checked my gas mileage it was 28.24...that's a combined city/highway driving..not stomping on it either..before i turbo'd the car my best was 31ish

 

[gimpo2]

sorry to thread jack, but do turbo's cause you to loose that much mpg??? I get a avg 28-30 mpg now, im going turbo this next spring, will my mpg drop that bad or did you just have something wrong etc??? THANKS

i had an extremely rich tune. the base map that comes on the F10 that Jaun gives you from Haltech. Its safe and it works but its really really rich.

 

[Tasty]

its ok i figured it out. spoke with moonman8 today we estimated i'm getting at least 22-23MPG. most of my driving is suburb driving. but to answer the questions. its got 33200 miles on it spark plugs have not been replaced, they will however be getting replaced next saturday. tires are fine.

You figured it out? So what was the problem? How can you come up with an "estimate" that is a good 7-8 mpg above what your actual mpg is and not want to find an explanation? Something is definitely not right, and you should keep checking until you find the culprit. 15 mpg using the trip odometer and doing the math would not sit well with me at all.

 

[Moonman8]

You figured it out? So what was the problem? How can you come up with an "estimate" that is a good 7-8 mpg above what your actual mpg is and not want to find an explanation? Something is definitely not right, and you should keep checking until you find the culprit. 15 mpg using the trip odometer and doing the math would not sit well with me at all.

I just helped him out with the math bit. He told me he had clocked 90 miles on barely more than a 1/4 tank of fuel. If you divide our tank capacity (14.5 gallons) by 4, you get 3.625 gallons. 90 miles divided by 3.625 gallons gives you 24.55 miles per gallon. Granted that the first quarter tank of fuel isn't the best estimate of average fuel mileage but at least it didn't result anywhere near the very disturbing 15 mpg. I don't really know where the number 15 originated from but I told him to keep me updated.

I advised to still change the plugs and do a basic tune-up on the car because he just bought it and doesn't know what kind of care it was given by the previous owner. His mileage is also a little over the 30k mark which makes it a good time to check things over and do some cheap easy maintenance just to gain that peace of mind.