m104 igintion control help - PeachParts Mercedes-Benz Forum

c280nz · #1 10-08-2008, 04:12 AM

howdy
i am after some info on the ignition/ coil wiring control setup on the m104
i have a 1994 model c280 with the 3 coil wasted spark system and are after any wiring diagrams as i wish to wire in the ignition control from my greedy emanage ecu,
at present i am running stock ignition timing but need some more control over this to help with power gains/reliability.

as far as i understand they use a negative signal wire to the three coils, is this correct, also wire colors etc/wire diargam would be awsome.

cheers for any help guys!!!
from logan

c280nz · #2 10-17-2008, 01:09 AM

well i found this wiring diagram online, but just need a bit of help reading it,
for the injectors and coils,
is that point in the middle X12/3 a common earth -ve,
and the Z9 middle point beside it is that a -ve point aswell?

if this is the case does the ecu use positive signal feeds to both fire the injectors and the coils? or am i wrong?

Turbo E320 · #3 10-17-2008, 02:21 AM

The Wires off the coils marked BK(black, pin 21) BK/YL(black/yellow, pin 9) BK/WT(Black/White, pin 10) are the signal wires to the ECU, in my car it is all located in the slot in the ecu labeled "Kammer E" which has around 48 pins(all numbered). The other wires that go to the circuit marked "x12" along with the injector wires are all for power it seems. The coils ground on the valve cover. Hope that helps.

c280nz · #4 10-17-2008, 04:13 AM

oh yep, so the signal wires for the injectors are ground loops?

Turbo E320 · #5 10-17-2008, 07:54 AM

If you mean that the injectors share a common ground then yes it appears so. The signal wires are the ones that run to the ECU.

whipplem104 · #6 10-17-2008, 11:01 AM

The injectors and coils are grounded to switch. Everything on mercedes is ground tripped. Other than a voltage cancelation such as the instrument warning.
The reason is that if there is a short to positive that the control unit is not damaged.
I am curious though on the ignition modules you guys are using, does it trip the check engine light. The ecu monitors misfires on that motor by monitoring ignition coil amperage. I would think that piggy backing the coils would effect that.

Turbo E320 · #7 10-17-2008, 12:24 PM

Im good. No CELs other than a o2 threshold becuase of my test pipe. I even retard my motor 10 degrees at 9 psi. I think c280nz's unit goes straight to the coils for timing adjustments while mine adds or substracts pulse strengths in the crank and cam wires.

Its pretty small too. Easily squeezes behind the passenger kick plate.

whipplem104 · #8 10-17-2008, 12:39 PM

That is interesting. Does your setup some how keep the fuel injection timing the same or does that get retarded also? Not that it would matter much.
I had always thought that on the newer cars that use crank rpm to detect misfires that you could unplug the injectors and coils and even though it would set a code it would not turn the light on. Then just run stand alone fuel ignition control. The rising rate fuel pressure regulator does a good enough job that I just never bothered to do anything else. At a certain point your just making a race car and all the bells and whistle are not wanted anyway.
MY goal right now is to get a thicker head gasket that will not require ignition retard at the boost levels you and I are running. I think it should be good for somewhere around 50 more horsepower. Maybe a little less.

Turbo E320 · #9 10-17-2008, 03:37 PM

The unit intercepts the fuel injectors as well and again adds and substracts from their pulse widths. The thing about the AEM is it does all the work before the signals hit the ecu so the car has no idea the unit is there. I wish I could convert my car to run a wideband as its primary o2 sensor though, the AEM is killer with wideband o2 tuning on the newer cars. It tunes wideband cars better than any comparable system out there. With its o2 tables you can completely reconfigure the closed loop settings. Of course my car has narrowbands and they are a PITA to get right.

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