Yes another 430 vs 320 and mpg question
07-07-2008, 01:49 PM
#26
MBWorld Fanatic!
I got a '99 430 too. No cool display. Here's my usual technique.
It takes 15.5 gallons to fill up when my gas light is on for awhile (I know we have 16.4 gallon tanks, but I haven't tested that yet
), I fill up, then I reset my trip meter, when my trip meter hits around 360-370 miles, my gas light comes on and by the time I get to a gas station it is between 375-390. I am able to put in about 15.5 gallons again.
Then I just calculate it 390/15.5. And my average MPG is about 25 when I get 390 to a tank. Then for every 15 miles I don't get, I subtract 1 from 25. So when my trip meter is at 375 to the tank, I know I averaged 24 MPG, 360 = 23 MPG...and so on. I always get 24-25 MPG (375-390 miles per tank) unless I do a lot of city driving or get stuck in bad freeway traffic. Then I've seen it go as low as 360.
I also have stock rims. How about the diameter of your tires. Maybe you are getting more miles than your odometer reads. I don't know... Maybe with a larger diameter you are going faster and further than what your speedometer and odometer reads. Maybe something to do with the adaptations, where even if you are light on the pedal, the ECU has already trained your car to run rich. Who knows. good luck.
It takes 15.5 gallons to fill up when my gas light is on for awhile (I know we have 16.4 gallon tanks, but I haven't tested that yet
), I fill up, then I reset my trip meter, when my trip meter hits around 360-370 miles, my gas light comes on and by the time I get to a gas station it is between 375-390. I am able to put in about 15.5 gallons again.Then I just calculate it 390/15.5. And my average MPG is about 25 when I get 390 to a tank. Then for every 15 miles I don't get, I subtract 1 from 25. So when my trip meter is at 375 to the tank, I know I averaged 24 MPG, 360 = 23 MPG...and so on. I always get 24-25 MPG (375-390 miles per tank) unless I do a lot of city driving or get stuck in bad freeway traffic. Then I've seen it go as low as 360.
I also have stock rims. How about the diameter of your tires. Maybe you are getting more miles than your odometer reads. I don't know... Maybe with a larger diameter you are going faster and further than what your speedometer and odometer reads. Maybe something to do with the adaptations, where even if you are light on the pedal, the ECU has already trained your car to run rich. Who knows. good luck.
and the wheels probably arent a big factor because i wasnt gettin much better mileage on stock wheels either....
ECU might have a bit to do with it since i got my ECU tuned (which is actually suppsoed to give slightly better MPG) but even before that - i wasnt getting GREAT mPG (about 19 MPG)...
07-07-2008, 01:57 PM
#27
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CLK430, SC430, RX330
Seems like a lot of cars are different even rolling off the assembly line. I got an Lexus SC430 right now that I can't get passed 19MPG.
07-14-2008, 12:51 AM
#29
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CLK 320
Just did a test. Got about 310 miles out of a tank to the last drop (almost). For a 15.5 Gallon tank it should be right around 20 miles to the gallon. I live in Houston and have a mixture of highway and city driving.
Will use the fuel injection cleaner and post updates.
99 CLK 320
310 miles/tank
20 MPG city/highway mixed.
Will use the fuel injection cleaner and post updates.
99 CLK 320
310 miles/tank
20 MPG city/highway mixed.
07-15-2008, 02:44 PM
#30
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2016 C450 AMG
2000 CLK430 coupe
I just had the spark plugs replaced and I regularly use Techron fuel system cleaner (2x a year). Before the spark plug change I got around 18-19mpg in mixed city use. On the highway I could get around 24. After the plug change Im getting about 20mpg overall. I took a trip to Philadelphia a week or two ago and averaged 26.8mpg (and thats WITH tolls). I'd swap the plugs out at 5 years! Mine were burnt to a crisp.....
I just had the spark plugs replaced and I regularly use Techron fuel system cleaner (2x a year). Before the spark plug change I got around 18-19mpg in mixed city use. On the highway I could get around 24. After the plug change Im getting about 20mpg overall. I took a trip to Philadelphia a week or two ago and averaged 26.8mpg (and thats WITH tolls). I'd swap the plugs out at 5 years! Mine were burnt to a crisp.....
07-15-2008, 04:37 PM
#31
Senior Member
I was getting an average of about 22.5 in my 430 (calculated by pump gallons and miles). In my 55 I'm down to about 20.8, but that includes a bit of spirited driving and not driving like a grandma.
07-15-2008, 09:57 PM
#34
Senior Member
That sucks! I was racing a STI the other night (including some dead stop and races from a roll and a few burnouts) for about 6 miles through some twisty roads and my mileage for that tank dropped to 19.4 combined with some freeway.
Sounds like you may need a tune up!
Sounds like you may need a tune up!
12-26-2008, 06:08 PM
#35
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2000 CLK430 Cabriolet
So I'm taking my CLK430 on its first long road trip (SE Michigan to Tampa Florida area) right now and the fuel mileage is far from impressive... my 5.7L Vette got 33.2 on this same trip and the CLK430 is at 22.1... speeds are generally from 60-80. I think I ran a can of injector cleaner through it before, but I'll run another through on the last tank... will new spark plugs make a difference in the mileage? The oil is fresh synthetic, air filters are as clean as can be, and I run premium only. 
Thanks!!
Ps- Car is a 2000 CLK430 and only has 58k on the clock... or did when the trip started.
Thanks!!Ps- Car is a 2000 CLK430 and only has 58k on the clock... or did when the trip started.
Last edited by BoostnBenz; 12-26-2008 at 06:14 PM.
