hmcl281

i read one of the other thread about the millage people got from there cars. i bought a e320 1998 wagon recently it has aobut 150000 miles and had a tune up afterward. also installed a k and n air filter. also checked the tire pressure recently.i mainly drive local street at about 25 mph. a lot of stop and go. i say i average about 12 to 15 miles a gallon. this does not seem right.

thanks for looking

ohlord

ditch the k/n install an oe filter from autohausaz.com.
B. Clean your maf,diy on benzworld.org w210 section diy.
C. check tire pressure 32front 38 rear.
D. even at 25 mph you are not in the most efficient range and eating up a lot of fuel stop and go.Nothing you can do about it other then the above and treat the gas pedal like an egg shell
E. throw in a can of seafoam injector cleaner at your next fill up(premium only)and see if that helps a bit.
F.Get out more often(on the hway)
G.enjoy
ohlord

hmcl281

thank for the reply

koskesh

if you're in a location that is extremely cold, engine runs rich due to the cold to keep engine warm. i'm in iowa and when it get's below 5 to 10 deg F my car uses up gas so fast.

RichardM98

I would suggest burning a few dollars of gas on the freeway first and carefully check mileage. These cars consistently get mid-20's MPG if everything is okay. If you do,then the problem is probably your short distance, stop and go driving. If you don't, then it's time to investigate.

hmcl281

i live in california, bay area so does not get too cold. check my tire pressure again and it was low on all the tires. filled it to the pressure suggested by the first post and seems to get better millage. will replace the filter and see if that helps a lttle

benzO320

Hey I was just wondering about the seafoam injector cleaner...
Where do I put it and does it really work? I've done everything else listed and mileage has gotten significantly better but I bet the seafoam will top it off.

hmcl281

what kind of millage r u getting?

tirona

i don't think you are getting that bad of a gas mileage for that kind of driving. i mean it's not good, but 15mph for mainly 20-25mph in stop and go traffic for a heavy 6-cylinder wagon doesn;t seem that out of ordinary. do you have the stock 16' wheels, or do you have bigger size? also are you using premium gasoline from a reputable gas station? maybe o2 sensors are going down south?

hmcl281

stock wheel. premium gasoline but from arco. i filled up with shell last time and seems better but that also might be because of the increase in tire pressure

benzO320

I do mostly 40mph stop and go driving with limited highway driving and I get about 16-18 mpg...
Which is normal I'm assuming but it can be improved...
Inline 6 E320 sedan w/ 136K miles.

nnathoo

Hi, I have E320 Wagon, 1998 as well.
According to the instruction, it says that pressure is 29 and 32. Only if you are speeding, to increase the pressure.
is that ok to increase to 32/38 as recommended?

ohlord

is fine.Also a lot of people running around with more then 100k miles on original o2 sensors time to change them is at 100k.
ohlord

ron m.

Before my car threw a code (P0170), I was getting 24 miles a gallon on a consistent basis (mainly conservative, highway driving sprinkled with some Italian-style ones... it's a wagon, for crying out loud). Since the check engine light, I've been at 21.5 mpg (or an efficiency loss of 10%). I strongly suspect that my MAF has a lot to do with this (along with a long overdue tune-up). I am going to follow the MAF cleaning instructions on Benzworld along with spark plug replacement this weekend. I hope this does the trick.

However, there are other things that affect engine efficiency, namely:
* fuel delivery (AFPR, fuel pump, injectors)
* carbon build-up
* Sensor malfunction (O2, MAF, etc).
* driving style
* Crappy California gas
* engine tune and timing
* engine compression and health
* weight
* aerodynamics

I'm sure I've left others out but that's the gist of it.

BTW, I also have a K&N filter(for 2 1/2 yrs). A week ago, I read a couple of comments about K&N being inferior in flow characteristics to OEM (which may be true... I have to see data). I supposed there's nothing wrong with going back to OEM, but Google research has given me the impression that K&N is harmless and marginally restrictive, at worst. I also read that K&N oil does not induce MAF failure... from the k&N site, of course.

BTW, is your car a 4-Matic? Drivetrain losses could also factor into your low mpg, but to be honest, 12-15 mpg is pretty darn low. How do you calculate that, per chance?

ohlord

you have is one code for the fuel trim p0170 and not the two codes p0173 and p0170 it is not the maf.If over 100k miles it is time to change the o2 sensors.Get rid of the k/n
autohausaz.com has them both at great prices.
Do you have the 17 mm boot removal tool?
pm me for tips on the plug job.

To the OP
For the 1998 some members have discovered a typo in the manual that had the oem plugs gapped at .032 the proper plugs are fr8dpp33 or NGK 7090 and they come out of the box gapped at the proper .039.I prefer the ngk7090.
A member on benzworld removed his plugs that were gapped at the wrong gap and increased his mpg from 21mpg hway up to the average we get on our wagon of about 27 hway.
So check those plugs if you have a 98 suffering poor mpg.
ohlord

ron m.

Yep, they're both there. I don't think I have the boot removal tool... but if that's the torx head, then maybe I do. I'll let you know if I stumble into anything.

I ended up buying the recommended plugs from Mercedesshop (whatever brand that is). Phil said they come pre-gapped but now I'll have to check again after your comment. Thanks.

ohlord

99 manual has the correct gap and the old plug number has been superseded
by the fr8dpp33 or the ngk7090 which you coulda had for $2.79 each if you read the post on spark plug meet up
17mm boot tool is a must and it is not the torx bit-----it is an offset tool about a foot long that gets in where no hand ever could and saves your hands,fingers,and plug wires most importantly from damage.
PM me if you need.
Clean your maf with crc brand maf cleaner per the diy on benzworld.org w210 diy section.You will have it removed for the plug change so you might as well do it then.
ohlord
"GOT CODES?"