95 W140 S600 Coupe V12 M120 Engine

Mercedes.
Haddixracing
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95 W140 S600 Coupe V12 M120 Engine

Postby Haddixracing » Tue Sep 09, 2008 4:02 pm

Well if you have ever had the pleasure of owning or working on a W140 chassis car (especially the V12) then you know how expensive the electronics can be. If you are unlucky like me then you know how problematic they can be as well. I dealt with numerous ASR problems and Limp Home mode occured daily. I replaced the electronic throttle bodies and was later told by the same dealer that I needed a new Egas module. That was the last straw. The parts alone were $4800 from the dealer. I am not made of money.

The solution, Megasquirt.

I am running MSnSExtra 1 with the V3.0 Board.
The stock setup uses a 3 tooth crank wheel with 2 VR sensors placed 60* apart on the flywheel. I tied these two sensors together to get a 6 tooth type signal. For tooth counter reset I am using the 2 stock Camshaft VR sensors also tied together. For conditioning the second trigger I am using the LM1815 circuit described in the manual. no modifications were done to the schematics. The crank sensor puts out 1.5Volts at cranking speeds so I had to turn the tigger pot up around 10-12 turns to get the signal stable at running speeds.

For coolant and intake temperature sensors I am using the stock MB units.

The stock injectors were used. They are High Z 16ohm.

The stock twin distributors were used as well as the twin coils. I am triggering them simply as spark A and spark B. The trigger point settings are 1,2,3,4,5,6
The trigger angle is 57*.

The stock throttle bodies were drive by wire type so I eliminated them. I am using a pair of throttle bodies from 2 Ford 4.6L Mod motors and the stock Ford Throttle Position Sensor.

For A/F monitoring I am using the Innovate LC-1.

I have one output circuit built on the proto board for driving a relay to switch the VVT solenoids on and off. The switch points are RPM based and they are on between 2200rpms and 4400rpms.

The stock electric cooling fans are controlled by the automatic climate control computer by the factory so I had no need to control them.

The transmission is pre-electronic version 4speed which is vac modulated.

The ABS system, Adaptive Dampening System, ASR system, were all removed. I did keep the stock ASR computer installed with only a few wires hooked to operate as the VSS buffer. The stock speedo system buffers the left front ABS speed sensor thru the ASR then out to the speedometer. All other control modules were completely removed.

I have the wiring in place for a Ford PWM IAC. I have not needed it so far. I am only in the initial tuning stages and that may change. It is possible though that I won't need it since this car produces over 350 pounds of torque at idle speeds, the A/C compressor doesn't even phase it.

So far I only have the motor idling. I still need to fabricate the throttle cables. I plan on making a bracket which attaches 2 throttle cables to the stock Throttle/Transmission cable adjustment point.

Install pictures will follow soon.
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cguenther
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Re: 95 W140 S600 Coupe V12 M120 Engine

Postby cguenther » Fri Oct 10, 2008 3:16 pm

hi,

please keep us informed about your progress and please add some pics.

best regards
carsten

Haddixracing
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Re: 95 W140 S600 Coupe V12 M120 Engine

Postby Haddixracing » Wed Dec 10, 2008 12:12 pm

A little update.

Progress has slowed down quite a bit. My mom's Suburban blew its head gaskets so I had to deal with that. Then my sister's car needed brakes. Then my Dad's van needed brakes and brake lines. Then my wife got pregnant! Woohoo! We bought an SUV which needed a little front end work. I have also been working on the baby's room. He's due March 30th.

I have managed to make a little progress on the Benz though.

The throttle linkage is finished. I still have to fabricate the brackets and attachment points for the transmission kickdown cable. After I finish that I will be taking everything to be sandblasted and powdercoated. I scrapped my original idea of using 2 throttle cables hooked to the pedal. I ended up using a soild rod between the two throttle bodies with miniature ball-joints on the ends. Then I hooked the throttle cable to the driver side and they work in unison.

I ran into a little snag along the way as well. I noticed in the initial tuning that I was dropping sync at a steady interval. After inspecting the camshaft wheel for the cam trigger I noticed that the two magnets on it were not placed 180* apart from the factory. They had them at 120* / 240* divisions. I ended up having to move the secondary magnet over 60* to get it to operate correctly. It was actually pretty easy. The magnets are housed in a thin metal wheel and simply press in from behind and have springs behind them to hold them in. I took out the 2nd magnet drilled a hole in the proper place and put it back in. Took all of about 30 minutes. Then I screwed up and busted the housing trying to snap the spring back in. It's made of pot metal. I ended up having to use JB weld to keep the magnet tight. The magnet can't fly out through the top due to a ridge in the magnet itself so the force of the spinning of the cam won't put any pressure on the JB weld. The only time it is holding it in is when the cam is stopped.

I think if I had to do this all over again I would have bought a trigger wheel and mounted it on the front of the crank pulley and everything would have been alot easier. I still may do that in the future if and when I convert this car to manual transmission. This is due to the fact that the crank trigger I am currently using is built into the flexplate which would be replaced with a flywheel in a M/T setup.

Haddixracing
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Re: 95 W140 S600 Coupe V12 M120 Engine

Postby Haddixracing » Tue Mar 31, 2009 9:45 pm

A little update.

I never got past the initial setup stage. I had it idling and drove it around the driveway a bit. I sold the car and the guy who bought it is returning it to stock fuel control.

mantai500
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Re: 95 W140 S600 Coupe V12 M120 Engine

Postby mantai500 » Mon Sep 12, 2011 3:16 am

Hi: I have a BMW M70 engine ( v12 ) in my car. I plan to run it with Ms II and use the original dizzy`s. Two vr trigger for ign. A+B ( 317 ). But how due i do it ? So one vr trigger A and the second trigger B? Thanks Jan.

NB. I am from Denmark so please dont be to hard on my english. :)

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kholman
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Re: 95 W140 S600 Coupe V12 M120 Engine

Postby kholman » Tue Sep 13, 2011 6:26 pm

mantai500: Success stories for users of all variants of MegaSquirt® who have successfully used MegaSquirt® on their vehicle, or who want to document their MegaSquirt® project.
If you are seeking assistance with your MegaSquirt® project, you should post your questions in the forums dealing with your configuration and MegaSquirt® product. You can find the list of forums here.
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