what could be wrong

[Sebby2390]

I was readin up on a couple threads, and most 318 owners are saying that they get anywhere from 28-33 mpg, im getting about 21, what could be causing this horrible gas mileage?

[SpasticDwarf]

Keep your foot out of it? :dunno

[strad]

Restricted fuel filter, worn out coils/spark plugs, vacuum leaks, worn o2 sensors, restricted cats, restricted air filter. Those are things I would (and have, with success) check and/or fix. I went from 24 to 30 city mpg with my M42.

[MisterBimmerMan]

Is your right foot made of lead? Are you a REVerend?:shifty

[Sebby2390]

no its not, i dont beat on my car, i constantly shift at 3000 rpm, typical daily driving....

[Sebby2390]

anyone else

[sctrini]

I've looked at the usual culprits of bad fuel economy with the exception of the coils and fuel filter. It looks relatively new. The last thing I did was change my O2 sensor and the car performs like it never has, at least with me as owner. However, I am still getting 23 MPG city. I think the reasons are quite simple...I have huge 7 or 8 inch wide BMW rims with 225/45/17 tires that are quite heavy for the lill M44. Heavy rolling mass does not help very much. I also love to run 3rd gear really hard and shift around 4000 - 4500 RPM. However, 23 MPG is still better than 14 which is what I get in my truck so I am content...sort of...

[espguitarist]

Yeah, well I get 17.3 in my 325i. I'm never on the highway. It used to be right around 19.5-20 but then I put my 17's on there and it went down.

[Sebby2390]

i actualy went to go and change my spark plugs today and found oil in there, so im gona be replacing my valve gasket cover, o rings, and possibly looking to change my o2 sensor.

[espguitarist]

i actualy went to go and change my spark plugs today and found oil in there, so im gona be replacing my valve gasket cover, o rings, and possibly looking to change my o2 sensor.

I just changed my valve cover gasket the other day. Very easy job, good luck. :)

[Bluebimma]

The 28-34mpg are usually highway. If im not mistaken, the 4cyl is only supposed to get like 25ish city anyways. The oil in the spark galleys can hinder spark and make for a weak ignition plus those 17s WILL impact a lot.

[Sebby2390]

yea and i have to replace the pvc hose also

[espguitarist]

The 28-34mpg are usually highway. If im not mistaken, the 4cyl is only supposed to get like 25ish city anyways. The oil in the spark galleys can hinder spark and make for a weak ignition plus those 17s WILL impact a lot.

Yep, we're hoping the oil in the spark galleys is what was causing the car to "kangaroo" up hills at about 55 mph. I also know that 17's are bad, lol....but I won't give up my Motorsport rims. I'm thinking about painting them black and leaving the rim silver....just thinking though.

[mchkc240]

How about 02 sensors? :rolleyes If you replace them you should see the difference.

[espguitarist]

How about 02 sensors? :rolleyes If you replace them you should see the difference.

Me or the OP? Only reason I'm not sure is because my mileage is worse than his, lol. If you're talking to me, then I did that a few months ago. I also haven't driven the car since I did all of the work on it (new oil filter housing, new water pump, new valve cover gasket, flushed the powersteering, flushed the coolant, cleaned out the alternator) so it may be better. There's also the fact that I live in the suburbs so I'm never on the highway, cause everywhere I go is relatively local.

[mchkc240]

Oh I was talking to the OP. City driving makes your gas mileage real bad. Especially stop and go.

[espguitarist]

Oh I was talking to the OP. City driving makes your gas mileage real bad. Especially stop and go.

Haha, okay, I wasn't sure.

Yup, there is a lot of stop and go in my area...unless you know backroads that are so awesome you can't resist to wail on the throttle. My area sucks for mpgs.

[Sebby2390]

just replaced the valve cover gasket, tube seals, spark plugs, rear shock mount, and shes runnnin like a beaut.

[Sebby2390]

and cleaned out the throttle body

[arctic28]

I just changed my valve cover gasket the other day. Very easy job, good luck. :)

not to threadjack but
im going to replace my VCG (along with air intake filter, spark plugs, and an oil change while im there) soon and im willing to bet money there's oil in the spark plug holes so,whats the best way to get it out of there?

[espguitarist]

not to threadjack but
im going to replace my VCG (along with air intake filter, spark plugs, and an oil change while im there) soon and im willing to bet money there's oil in the spark plug holes so,whats the best way to get it out of there?

My dad did it while I was stuck cleaning the crusty old valve cover, so I didn't see him do it, but as far as I know, he just took out the plugs and let it drain into the engine. I'll call him and ask.

Edit: Yup, just get a rag down in there first and try to soak up as much as possible, then remove the plug and let it drain into the engine.

[Sebby2390]

or just take the plugs and everything out, put a rag over the holes and it will spit out all the gunk.

[Sebby2390]

alright, so i just filled up, and now im down to 3/4 of a tank, and i got 75 miles out of it.

thats like 17 mpg,

WTF could be wrong =[

[Sebby2390]

i picked up a fuel filter, yet to replace it, but can the fuel filter make that much of a difference? or is it most likely my o2 sensors?

[espguitarist]

or just take the plugs and everything out, put a rag over the holes and it will spit out all the gunk.

Actually we did that too.....lol, we did so much work on that car, I have a hard time remembering everything. 25 hours of labor in 5 days.

[Sebby2390]

these cars man... i get a new problem everyday.

[espguitarist]

Mine's at the shop right now getting painted. I can't wait to get it back. All the engine work is done so it'll be running like new, all the door dings will be popped so it'll look like new....life will be good for a while....until I get the bill from the paint shop.

[gldfshkpr]

Edmunds gives the following MPG specs -
Fuel Fuel Tank Capacity: 16.4 gal. EPA Mileage Estimates: (City/Highway) Manual: 23 mpg / 31 mpg Automatic: : 23 mpg / 31 mpg Range in Miles: (City/Highway) Automatic: 377.2 mi. / 508.4 mi. Manual: 377.2 mi. / 508.4 mi.

That's for a brand new car. Given age and wear, those figures will surely fall. I aim for 25 MPG on average. I was getting @20 before I fixed a stuck crankcase valve and put in a new fuel filter. These cars definitely have to been looked after. The rewards are far greater than the effort IMHO. Replacing a fuel filter on these cars is a breeze. Especially if you have an extra set of hands. Like someone said, check/replace air filter, oil change, spark plugs (in your case a seal as well) etc. Maintenance is key.

[arctic28]

My dad did it while I was stuck cleaning the crusty old valve cover, so I didn't see him do it, but as far as I know, he just took out the plugs and let it drain into the engine. I'll call him and ask.

Edit: Yup, just get a rag down in there first and try to soak up as much as possible, then remove the plug and let it drain into the engine.

alright thanks a lot

[Sebby2390]

alright so i finally got my car computer scanned, and the air flow meter is what it detected...

anyone no any legit sites where i can get a good priced meter?