To the track guys out there , i was wondering how they set there mixtures on the track with there MB's? you guys running O2 sensors or EHA on or off? I know with the old CIS porsches , they disconnect the O2 run a few laps to warm up the engine and richen the mixture , then set it back to drive home with. or is there racing O2 sensors and EHA? thanks Dave GO KIMI!!!!!!!!!!

I use a O2 sensor to supply display with fuel throttle mixture info. The EHA stays unplugged except on test days when I have a rheostat connected. Then I set differential pressure for those conditions.

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Doc, does unplugging the EHA throw the system into open loop?

Unplugging the EHA elimanates ALL electronic inputs & then puts the system into FOM(fixed operational mode)
The injection system is mechanical! The electronics only there to enhance emission levels. & for cold running.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

So if an M103 is guzzling gas (10mpg) in both FOM and closed loop, then it is more likely a mechanical problem?

MB Doc .
Are you using a stock MB fuel press. reg? or do you have a adjustable one? Does bosch make injectors that flow more fuel for the 16v?
Also how are you figuring you are riching the mixture , from the O2 meter? About how many turns of the mixture screw about? (summer day)

I really like how the 16v pulls with the EHA off but it sucks following someone slow, may be I can rig a switch on the dash
to turn it on and off at will

The 16V uses a pressure regulator that opens around 5.8 bar.
The 420 & 560SEL's fuel pressure is 6.2-6.4 bar. The only difference is the regulator. The injectors from the 420/560 engines also flow more fuel, but the line connections are different.

Yes the O2 sensor info to my meter allows good info on fuel mixture.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator