I've got a complicated problems with my 300E.
Bought it 4 months ago @ 120k miles.
It was on LPG,first i removed LPG,because there were Fuel/Power problems on it.
After removing LPG system completely,increased power,but consumption was disaster. (150miles full tank)
Checked air flow meter/sensor it was some higher from factory/original position.Mechanic fixed it.Fuel/power normalized but still not satisfactory for straight m103.
Several mechanics tried to adjust mixture but not satisied fuel consumption is still high (16-18 in city).And not run as 180 HP.
What should i do?No professional mechanic in my city.

Eha is working and turned 1/4.
I' checked and sure no leaks somewhere
exhaust readings at factory settings 500-700 (NO CAT) @ idle
o2 sensor readings 0.4v-0.5v @ idle.
x11 (2-3) reading are 2.5 - 2.8 volts @ idle (Correct 6.5V ? If like that,why co reading is normal/in limits.

Please,please and please help me.
Thanks...

I would have thought around 20 MPG city was average for a M103. Can anyone else confirm this ?

Judging by what your saying about CO and O2 sensor readings, everything is normal. However I know nothing about duty cycle so someone else will help you with this.

You should be getting ~20mpg +-2/3 depending on your foot. Best I have ever seen in my 300TE is 22mpg (avg 17), my 260E 24mpg (avg 21) and that was on long runs 60mph for 200mi+.

You should definitely be getting at LEAST 260mi to a tank before the light comes on. 300mi before the light comes on is ~21mpg as that is what I get day-to-day in the 2.6.

Seeing as the O2 sensor is saying the mixture is correct, with the conversion was the correct ECU Module used? Could be a computer error causing the problem.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

computer working?

We just went through something similar with a friends 300e..computer was bad, and mixture was all wrong.....gas millage was also way off.....

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1993 300E, 2.8 M104 .....

I've gotten 29 and 31 mpg on the highway...wouldn't put the numbers too low.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Sorry no harm meant, but for a M103 I don't believe you...Unless you are driving downhill, your odometer is probably counting miles incorrectly. Most M104's which get much better fuel economy struggle to get above 26/27.
If you really did achieve above 30mpg, you would be the first and let us know what you are doing!!

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

ERCUZ what's your location?

Depending where you had the original LPG conversion done, the timing is altered for the LPG rate of burning. Done by the infamous R16 resistor.

Have you changed your injectors and injector seals and guides. LPG is not kind to these things.

I filled up yesterday. 22mpg out of my M103 city driving. Regularly get 30mpg country driving. (Imperial gallons)

I replaced injectors o rings.Injectors running normal.

agreed ps2cho.How can you do?

Hope its working.i dont know how to test it and dont know ecu's error symptoms obvilously.

ercuz, is this a California version car? The duty cycle number is about right if you have the CA computer installed, rather than the 49-state federal computer.

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

No California version.Here is vin details

VIN WDB1240301A474341 Model 300 E Chassis 1240301A474341 Engine 103983 12 068796 Transmission 722320 02 935996 Order 0 5 217 12578 Delivery date 00.00.00 Dealer Frankfurt branch (217) Interior velours blue (972)

and sorry,i dont know whats the mean of ''CA COMPUTER''

25 mpg is about the highest I got on the highway. Usually 17 ish in the city.

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1989 300E

2005 Acura TL

2011 Hyundai Elantra Limited

Swing hard! Take chances!

I tracked the distance by GPS so no odometer variable. Average speed was about 60mph, all highway. Each time the fuel was filled up right to the lip for consistency. I didn't believe it at first either but I consistently get upwards of 25mpg on the highway every time I do out my mileage. My fuel pumps are making a ton of noise so maybe they just aren't pumping as much in their old age, idk. I generally get pretty good mileage out of cars, I've hit 30mpg in my 300SD several times which is the "impossible number". I don't think I have much of a feather foot, but I guess the numbers suggest otherwise. I used to get about 28-29mpg out of my twin turbo stealth, and hit 42mpg in my gf's eclipse. Been doing mpg calculations since I was 16 too, so no calculation error here. Plus my city driving (90% of mine) is pretty typical, 15mpg.

edit: sorry for the thread hijack

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

1990-92 300E are with 2.87 rear diff. ratio. 86-89 with 3.07. It may explain better MPG on HWY.

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1987 300D Turbo 170K (sold)
1990 300E
1992 300D 2.5 Turbo
2003 Audi A6 4.2