Sudden increase in my gas consumption (E320) Any suggestion?
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E 320 (2001)
Sudden increase in my gas consumption (E320) Any suggestion?
Hello, I used to get an average of 21 MPG, which I was happy with and all of a sudden I get 18.5 MPG. No modifications in the way I drive. My E320(2001) is well cared for (73,000 miles), my tires are correctly inflated, etc. I wonder why the change... Spark plugs? Do I need a tune up? Suggestions warmly welcomed. Best, Chris (Miami)
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I've got the same thing going on in my 97 E320. 130k miles. It really started when I changed from 10w30 mobil1 to 10w40 dino oil.
I changed the plugs and wires but that didn't help. Fuel filter is also on the list. I'll be going back to mobil1 in another 500 miles... I may look into changing the MAF if nothing else works.
A few people have suggested that summer gas blend with ethanol will hurt gas mileage.
Any other ideas?
I changed the plugs and wires but that didn't help. Fuel filter is also on the list. I'll be going back to mobil1 in another 500 miles... I may look into changing the MAF if nothing else works.
A few people have suggested that summer gas blend with ethanol will hurt gas mileage.
Any other ideas?
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From: West Virginia
2001 E320 RWD - Brilliant Silver/Ash: 100,000+
Daptin
I have the same car that you do, but I will relate the reason for my older E430 increase (@ 125k) in gas consumption.
I needed one of the O2 sensors replaced because it failed. However, The CEL was on in my case. The service writer said that the car was running rich as a result, hence the decreased mpg.
I agree with the ethanol answers - I will not knowingly use ethanol-containing gasolines, but there are some areas where we don't have a choice. My main reason for avoiding it in all of my cars, is that I don't think it is good for the engines.
If switching to non-ethanol fuel does not help, I would try a tune-up next. I have a hard time swallowing any spark plugs in any automobile lasting 100,000 miles. Do you notice any difference in the way the engine performs?
Good luck,
M
I needed one of the O2 sensors replaced because it failed. However, The CEL was on in my case. The service writer said that the car was running rich as a result, hence the decreased mpg.
I agree with the ethanol answers - I will not knowingly use ethanol-containing gasolines, but there are some areas where we don't have a choice. My main reason for avoiding it in all of my cars, is that I don't think it is good for the engines.
If switching to non-ethanol fuel does not help, I would try a tune-up next. I have a hard time swallowing any spark plugs in any automobile lasting 100,000 miles. Do you notice any difference in the way the engine performs?
Good luck,
M
Last edited by Musikmann; Aug 8, 2006 at 12:18 PM. Reason: adding to message
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From: Kansas City. U.S.A.
2000 E320 Sedan
With 73,000 miles, yeah u may need to change sparkplugs even thu it is suppose to be every 100,000 . But this will not 100% fix the problem trust me. I would make sure that you replace the Gas filters first "Shoudl be replaced every 80k miles". Make sure you measure your MPG w/o A/C being on and test it on the highway and not city since city driving varies from area to area ..etc... be consistant on your gas padel the way you drive to measure accurately. Also check Air filters, Make sure you use 91 or higher on Octain Premium unleaded gasoline. What about your tires thread, I am sure it is not as deep as they were when you measured 21 mpg !!
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'98 E320 4Matic, '85 380SL
I too would suspect ethanol as the culprit. Ethanol has less BTU/gal than gasoline. I've found that 10% ethanol knocks off at least 2-3 MPG.
21 MPG sounds low to me, let alone 18. I log every fill-up and calculate my mileage. I see about 24-25 MPG on average with mixed city/highway miles and get 28-29 on highway trips. I drive fast on the freeway (80-90 MPH) but generally accelerate slowly.
21 MPG sounds low to me, let alone 18. I log every fill-up and calculate my mileage. I see about 24-25 MPG on average with mixed city/highway miles and get 28-29 on highway trips. I drive fast on the freeway (80-90 MPH) but generally accelerate slowly.
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'98 E320 4Matic, '85 380SL
Usually they disclose on the pump the ethanol content of the gas. The use of ethanol helps reduce smog, albeit at higher cost and reduced efficiency. Ethanol is hard on the fuel system (dessicates rubber seals, hoses, etc) and should be avoided in classic cars.
Gas and water don't normally mix in a station's tanks. The water settles to the bottom and the gas floats on top. Ethanol is a polar solvent, which means that it dissolves any water in the gasoline (bad).
Gas and water don't normally mix in a station's tanks. The water settles to the bottom and the gas floats on top. Ethanol is a polar solvent, which means that it dissolves any water in the gasoline (bad).
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Joined: Aug 2006
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From: South Carolina
2000 E-430
Hey Guys! New to the forums, so please bear with me. From my experiences, decreased fuel economy is one of the signs of engine sludging. 98-02 engines(in particular the 112(V6) and 113(V8) engines) were bad for oil sludge buildup. have you noticed a excessive build of carbon around the exhaust tips. If so, it would definately lead me to believe your engine is sludging up. In '98 and up engines, mobil 1 synthetic is used. We were using 0W-40 until a couple of weeks ago. We now use 5W-40. What kind and grade of oil are you running?
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From: Kansas City. U.S.A.
2000 E320 Sedan
Good observation. Possible I guess. If he is not using Mobil1, buildup can happen. Note: using premium unleaded (E10) should not affect any new model caskets ..etc. It is a myth that it does. They improved the E10 in 1995 and there is no single documented correlation between E10 and Car damage whatsoever.
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E 320 (2001)
Increased gas consumption...
GUYS... THANK YOU, ALL OF YOU! Very pertinent advice... I will check if by any chance I am getting ethanol without knowing it. Had no idea the choice of oil was so important! Wonder if the choice of gas is important too. By the way, how important is it to use premium gas? That's what I use most of the time, but once in a while, I fill her up with regular. Is that a BAD IDEA? Should I use ADDITIVES, and if so which ones? All this is very important to me, as my wife strongly hints I should get another car with better mileage ratio. When I indicate 18.5/21 MPG, it's under my regular driving conditions, with the A/C on, of course (this is Florida!). Maybe I should use an economy A/C setting... The threads on my tire could be deeper, but that does not account for the SUDDEN increase... Thanks again, you are great!
Chris, in Miami
Chris, in Miami
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From: South Carolina
2000 E-430
I would never run regular unleaded. Your engine was designed to be run on premium gasoline only!!!. You can get away with running midgrade, but it is still best to use premium. Using the improper grade of fuel can lead to a decrease in engine performance.
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E 320 (2001)
Update
Thank you again! The first thing I did was to double-check on my tires pressure. Then I changed the oil to Mobil 1. Also, I am sticking to Premium unleaded only. Wonder about the Ethanol content... how can I find out and avoid Ethanol? I am already seeing an improvement... Wonder also if I should consider replacing the spark plugs...
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From: South Carolina
2000 E-430
I wouldn't worry about the ethanol content. As long as its premium gasoline, the ethanol content will not be an issue. How many mile do you have on your spark plugs? It may help somewhat to replace them.
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E 320 (2001)
Originally Posted by Z-Man
I wouldn't worry about the ethanol content. As long as its premium gasoline, the ethanol content will not be an issue. How many mile do you have on your spark plugs? It may help somewhat to replace them.
The original spark plugs have 74000 miles on them. My local "Pep Boys" would charge $240.00 to change them, but I would not entrust my E320 to them, except for an oil change... after taking a look at the engine, their mechanics told me it was an 8 cylinder! And I thought I knew nothing about engines! So, I would probably turn to my usual MB specialist. However, when he changes the oil he probably uses the cheapest brand available. Now I switched to Mobil 1, I really notice a difference (thanks to this Forum!). I don't want him to install the cheapest spark plugs either...
I came across a website http://www.lubedev.com/smartgas/tips.htm that recommends unusual solutions to improve mileage (for example: add 2 or 3 ounces of ACETONE into 10 gallons of gasoline and that will increase mileage "about 25-percent or more"). Either the author, Louis LaPointe, is a genius or a nutcase... But he has a huge website and appears to know a lot...He also has this advice about spark plugs (I quote):
"6. Use NGK V-Power spark plugs because they have a proper resistance level that will not short out the high voltage secondary during moist or very cold weather. Avoid platinum or palladium plugs. Other plugs (Champion or AC) have excessive resistance that wastes spark energy. Set the gap to .030 for best results for most cars. Too wide a gap causes a needless waste of amperage. The milliamps actually fire the mixture rather than the voltage. AMPS = HEAT. You cannot believe all the popular hype about VOLTAGE. But be certain your plug wires or cables are perfect. I now use the superb Kiker Wires for mileage. Replace your cables if they are over five years old. NGK also makes excellent plug wires. Bad cables will cause missing and poor MPG. Some plugs that come set at .060 can be reduced to .035. You may wish to contact PatKiker@yahoo.com for the best possible spark plug wires that will add MPG to your car or truck. We proved they work. See www.KikerPerformance.com."[/I]
I suspect my spark plugs are ripe for a change, but I would like to make sure I get the best for my E320 and also the correct adjustment. Would you have any further advice? Best, Chris (Miami)
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From: South Carolina
2000 E-430
If I were you, I probably wouldn't listen to that guy. If you owned a chevy or ford, I wouldn't hurt to try. But I'm almost sure he doesn't have a mercedes layin around to test on(especially if he is worried about saving gas
!) Not only do I own a mercedes, but I work on them for a living. If there was something that could be done to increase fuel milage(additives, etc.) I would have probably attempted it. The Spark Plugs, oil, etc. that you can get from your local dealer are definately the best bet for your vehicle. The plugs that dealers sell are designed for your vehicle(I believe yours uses platinum plugs, and they are already gapped correctly unlike others from the local part store), and the plug suppressors(plug wires) are designed to have a specific resistance in them(your vehicle uses two different types of suppressor wires). Buying aftermarket(pepboys, autozone, Napa,etc.) wires, plugs, oil filters or other parts may be cost saving at first, but will probably have a negative impact at some point down the road. It may cost a litte more now, but you will thank yourself later. Hope this helps, If you have any other questions, feel free to let me know.
!) Not only do I own a mercedes, but I work on them for a living. If there was something that could be done to increase fuel milage(additives, etc.) I would have probably attempted it. The Spark Plugs, oil, etc. that you can get from your local dealer are definately the best bet for your vehicle. The plugs that dealers sell are designed for your vehicle(I believe yours uses platinum plugs, and they are already gapped correctly unlike others from the local part store), and the plug suppressors(plug wires) are designed to have a specific resistance in them(your vehicle uses two different types of suppressor wires). Buying aftermarket(pepboys, autozone, Napa,etc.) wires, plugs, oil filters or other parts may be cost saving at first, but will probably have a negative impact at some point down the road. It may cost a litte more now, but you will thank yourself later. Hope this helps, If you have any other questions, feel free to let me know.
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Joined: Apr 2006
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From: Richardson, TX
'04 Cobra & '04 S430
You could always pull a plug out of the engine and see if it looks good. The condition of the spark plug currently in your engine could be a better indication of if it needs to be replaced or not.
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E 320 (2001)
Originally Posted by Z-Man
If I were you, I probably wouldn't listen to that guy. If you owned a chevy or ford, I wouldn't hurt to try. But I'm almost sure he doesn't have a mercedes layin around to test on(especially if he is worried about saving gas!) Not only do I own a mercedes, but I work on them for a living. If there was something that could be done to increase fuel milage(additives, etc.) I would have probably attempted it. The Spark Plugs, oil, etc. that you can get from your local dealer are definately the best bet for your vehicle. The plugs that dealers sell are designed for your vehicle(I believe yours uses platinum plugs, and they are already gapped correctly unlike others from the local part store), and the plug suppressors(plug wires) are designed to have a specific resistance in them(your vehicle uses two different types of suppressor wires). Buying aftermarket(pepboys, autozone, Napa,etc.) wires, plugs, oil filters or other parts may be cost saving at first, but will probably have a negative impact at some point down the road. It may cost a litte more now, but you will thank yourself later. Hope this helps, If you have any other questions, feel free to let me know.
!) Not only do I own a mercedes, but I work on them for a living. If there was something that could be done to increase fuel milage(additives, etc.) I would have probably attempted it. The Spark Plugs, oil, etc. that you can get from your local dealer are definately the best bet for your vehicle. The plugs that dealers sell are designed for your vehicle(I believe yours uses platinum plugs, and they are already gapped correctly unlike others from the local part store), and the plug suppressors(plug wires) are designed to have a specific resistance in them(your vehicle uses two different types of suppressor wires). Buying aftermarket(pepboys, autozone, Napa,etc.) wires, plugs, oil filters or other parts may be cost saving at first, but will probably have a negative impact at some point down the road. It may cost a litte more now, but you will thank yourself later. Hope this helps, If you have any other questions, feel free to let me know.
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E 320 (2001)
Originally Posted by Huachipato
You could always pull a plug out of the engine and see if it looks good. The condition of the spark plug currently in your engine could be a better indication of if it needs to be replaced or not.
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From: Princeton NJ
2015 E350 4matic Sport and 2011 C300 4matic sport
I am surprised you are satisfied with you old mileage. I too get a regular 26-27 miles per gallon on the road.
I think with the gas crisis that is going on that some states have dropped some envirornmental regulations and therefore changed some additives. But most of these changes should boost millage not deminish it.
Something else is going on with your car...
I think with the gas crisis that is going on that some states have dropped some envirornmental regulations and therefore changed some additives. But most of these changes should boost millage not deminish it.
Something else is going on with your car...
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From: South Carolina
2000 E-430
Originally Posted by Daptin
Thanks again Z-Man. Yep, if you could get a 25% increase in mileage with a few ounces of acetone, there would be a cottage industry of people selling acetone under fancy names. And I know for a fact that he does not own any fancy car. As I said, I'm not going to be a guinea-pig, only to report later that my engine exploded... Just by switching to MOBIL1, my mileage improved from 18.5 to 22.1 MPG. The next step: I have installed 4 new Michelin tires and I'll see if the mileage improves any further (especially checking the pressure: 28 in front and 32 in rear). 22.1 MPG is an average including mostly city and some highway, with A/C constantly on. Do you think it's a good MPG or can it be improved? According to my Mercedes mechanic, my 74,000 mile plugs are still good...
Last edited by Z-Man; Aug 24, 2006 at 08:39 PM.
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From: Western Michigan
2003 E320 4Matic Wagon & 1997 E320
All above are possible causes. However, there is a very simple item that could cause a gradual or sudden fuel mileage drop.
What is your coolant temperature? Is it above 80 degrees Celsius when the car is warmed up? If not, the thermostat needs replacing. They typically last 60k miles. The most often failure mode is partially stuck open and when that happens, the engine will take a long time or never fully reach operating temperature.
What is your coolant temperature? Is it above 80 degrees Celsius when the car is warmed up? If not, the thermostat needs replacing. They typically last 60k miles. The most often failure mode is partially stuck open and when that happens, the engine will take a long time or never fully reach operating temperature.
