Where did my mpg go?
Thread Starter
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Joined: Jun 2004
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
Where did my mpg go?
Let me start out by saying once upon a time I was getting like 27 mpg while on highway and happy with it. I added a few mods to include pulley, intake, and ECU.
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
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From: PA
S600, GL450, GLC 43
Let me start out by saying once upon a time I was getting like 27 mpg while on highway and happy with it. I added a few mods to include pulley, intake, and ECU.
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
Its probably dumping more fuel for that lovely pulley now, hence the decrease in MPG
Since I added my pulley 2000 miles ago, my lifetime average went from 17.9, down to 16.2.
See yeah
Thread Starter
MBWorld Fanatic!
Joined: Jun 2004
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
Oh- ok. I was starting to think ECU but since I haven't been flooring it- kind of dismissed it. I was thinking only the ECU under specific trottle conditions.
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Joined: Oct 2007
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From: New Hampshire
2003 C32 AMG, 2003 E39 M5
2 days seem like a long time but how many miles did you put on in 2 days? For instance in 2 days I put on about 35 miles. I would think the ECU needs a certain amount of miles to go back to stock driving mix. There is a way to reset your ecu also some where posted here.
I am stock and the most I have ever got was 25-26 on the highway.
I am stock and the most I have ever got was 25-26 on the highway.
Let me start out by saying once upon a time I was getting like 27 mpg while on highway and happy with it. I added a few mods to include pulley, intake, and ECU.
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
Thread Starter
MBWorld Fanatic!
Joined: Jun 2004
Posts: 1,140
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
2 days seem like a long time but how many miles did you put on in 2 days? For instance in 2 days I put on about 35 miles. I would think the ECU needs a certain amount of miles to go back to stock driving mix. There is a way to reset your ecu also some where posted here.
I am stock and the most I have ever got was 25-26 on the highway.
I am stock and the most I have ever got was 25-26 on the highway.
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From: Philadelphia, PA
2008 A8L, 2002 996TT X50, 2009 X5
Let me start out by saying once upon a time I was getting like 27 mpg while on highway and happy with it. I added a few mods to include pulley, intake, and ECU.
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
Recently I can't get beyond 23 mpg so out of an experiment I removed the code3 intake and drove the car over two days and got only an increase of 1 mpg. During the driving, I did not change my driving habits. So, can someone tell me where I have lost my mpgs?
One point - 27 mpg is just crazy for a completely stock car... was that just an instantaneous reading, or a trip average? I used to hit about 24 mpg on trips while stock... now, those same trips I hit about 23 mpg. In mixed driving over thousands of miles, I've noticed about a 1-1.5 mpg reduction since all of my mods... not too shabby IMHO for the big jump in performance.
I would suggest you hit a dyno and get your A/F ratio. Once you have that data, call Jerry to discuss if there are any ECU revisions he could make that might help your mpg. Most here on the forums are probably getting an ECU tune to unlock the max safe power available, so I would guess the tunes are being optimized for that... not necessarily keeping mpg as close to stock as possible. GL!
Thread Starter
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Joined: Jun 2004
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
Probably ECU tune (but, because of the pulley). On a forced-induction vehicle, if you increase boost (i.e. air being shoved into the engine), you have to increase fueling (i.e. via the ECU fuel map) to maintain a safe and proper A/F ratio. The stock ECU can do this on its own to a degree, but the ECU tune directly addresses it. I believe there may be other parameters as well (S/C activation/deactivation thresholds for speed and load, etc.) that potentially could affect mpg, and IIRC can be tweaked with the ECU programming.
One point - 27 mpg is just crazy for a completely stock car... was that just an instantaneous reading, or a trip average? I used to hit about 24 mpg on trips while stock... now, those same trips I hit about 23 mpg. In mixed driving over thousands of miles, I've noticed about a 1-1.5 mpg reduction since all of my mods... not too shabby IMHO for the big jump in performance.
I would suggest you hit a dyno and get your A/F ratio. Once you have that data, call Jerry to discuss if there are any ECU revisions he could make that might help your mpg. Most here on the forums are probably getting an ECU tune to unlock the max safe power available, so I would guess the tunes are being optimized for that... not necessarily keeping mpg as close to stock as possible. GL!
One point - 27 mpg is just crazy for a completely stock car... was that just an instantaneous reading, or a trip average? I used to hit about 24 mpg on trips while stock... now, those same trips I hit about 23 mpg. In mixed driving over thousands of miles, I've noticed about a 1-1.5 mpg reduction since all of my mods... not too shabby IMHO for the big jump in performance.
I would suggest you hit a dyno and get your A/F ratio. Once you have that data, call Jerry to discuss if there are any ECU revisions he could make that might help your mpg. Most here on the forums are probably getting an ECU tune to unlock the max safe power available, so I would guess the tunes are being optimized for that... not necessarily keeping mpg as close to stock as possible. GL!
all normal... thanks for the wealth of information posted guys.
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Super Member
Joined: Oct 2007
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From: New Hampshire
2003 C32 AMG, 2003 E39 M5
I am guessing a 100 miles was not long enough for the ECU to fully adjust back. That is just a guess though.
If you were getting 23 with the upgrades put them back on and enjoy the hell out of the car. Hell I had a new Grand Prix (6 Cylinder) I could not break 25 MPG with on my business trip this week. So your 23 MPG with your power upgrades sounds dam good.
If you were getting 23 with the upgrades put them back on and enjoy the hell out of the car. Hell I had a new Grand Prix (6 Cylinder) I could not break 25 MPG with on my business trip this week. So your 23 MPG with your power upgrades sounds dam good.
I only did like 50 miles each day but took the same route and did the same driving style each day to make the comparison. With only a 1 mpg gain by removing the code3, I'm putting it back and based on what the other post mentioned with the ECU and your post here, it looks like 23mpg is close to normal. I know you gotta pay to play
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02 C32 AMG
just turn the key to position two, press the throttle all the way for like 5 seconds, turn the key back to position one, and then take your foot off the throttle. wait 30 minutes. same result. i only wait for 3 minutes and its fine too.
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From: Philadelphia, PA
2008 A8L, 2002 996TT X50, 2009 X5
there is an easier way to reset the ecu so you dont have to mess with the battery and the random codes and warnings that you could get if you do that.
just turn the key to position two, press the throttle all the way for like 5 seconds, turn the key back to position one, and then take your foot off the throttle. wait 30 minutes. same result. i only wait for 3 minutes and its fine too.
just turn the key to position two, press the throttle all the way for like 5 seconds, turn the key back to position one, and then take your foot off the throttle. wait 30 minutes. same result. i only wait for 3 minutes and its fine too.
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CLS55 Designo 030
there is an easier way to reset the ecu so you dont have to mess with the battery and the random codes and warnings that you could get if you do that.
just turn the key to position two, press the throttle all the way for like 5 seconds, turn the key back to position one, and then take your foot off the throttle. wait 30 minutes. same result. i only wait for 3 minutes and its fine too.
just turn the key to position two, press the throttle all the way for like 5 seconds, turn the key back to position one, and then take your foot off the throttle. wait 30 minutes. same result. i only wait for 3 minutes and its fine too.
You are right... although I think that's throttle parameters only.
I was saying JUST to be sure.
