no ignition

Hi Gentlemen

Greetings on a calm summer day from Istanbul.

My car broke down two days ago all of a sudden. (mb 350 slc-year 1972-107023-116942 engine-djet)
The engine dropped dead while I was driving when I had to push the brakes.
After couple of tries I was able to restart but letting go of the gas pedal resulted in dying of the engine again.
So I tried to continue by pressing the gas pedal and the brakes to reach back home.
But this effort was in vain.
After several times the engine did not start again and the car was towed away to the repair shop.

when turn the key first I hear the buzz of the fuel pump, the starter is moving, I can smell the fuel but the engine won't start.
the electrician who has checked the ignition coil claims there is no voltage.
I have made some research in the forum and read couple of articles regarding this problem.
I have downloaded the pdfs regarding tsz description and checking of the units involved.
my switchgear unit 0227 051 022 is buried in the front left under the wheel house
I have the blue and the silver resistors and the ignition coil.
I do not remember the part no of the Bosch ignition coil but my spare is the 022 1122 001.

1.) I have a Standart multimeter the reading I get from the resistors are the same for both types (blue and silver) is b/w 0,7 and 1.2 ohm. I got the same values from the brand new ones I have obtained from my spare parts guy.(I measure all resistors detached from the copartment on a table) I guess the multimeter I have is not suitable fort his job. Is there any brand recommended for this purpose as I read a lot in Volker s comments that instruments used must be calibrated.
2.) The instructions in the pdfs use terminology I am not familiar with Is there any video I could watch for a better understanding?
3.) In case the switch gear is broken Is it possible to repair it? I see refurbished ones in some websites

One last question is regarding the erratic behaviour of the rpm gauge and related engine sound.
Before the car broke down I was on the highway for 20 min driving with lights on (90km/h-ca. 2700-3000 rpm) I signaled to the right to change lanes and the lights in the rpm gauge started to go on and off erratically together with the rpm needle going up and down but engine was turning normally. At the same time the right signal and the high beam indicators lights were also going on and off.
Since I wrote to this forum couple of times regarding the sawing effect of the engine I was wondering If these two incidents may be connected?

Best Regards
Juan

Hi Juan,

what you report sounds like a ground problem. Please check your ground copper band from engine to chassis and from battery to chassis. A varying ground connection could create all kinds of effects on D-Jetronic too. All injectors are grounded in one position on engine.

Ignition coil is correct and you will find test instructions in page 4 of 07.5-519 TSZ switchgear (wheel house units) and values are in 07.5-520 . Please note that you have to put ignition contact in clsoing position to measure. Do not keep it in that position for too long as ignition coil and resistors or ignition module might burn. If you module is burned, I have one here for you my friend.

I had a problem on my later Kjet W123 with an erratic tacho, it turned out to be the ignition switch gear, the signal to the tacho comes from it. This may be your problem, see if you can get a good unit to try.

Hi unknown ismoz,

would be great if you could sign with your firstname as everyone else does here usually.

W123 is different. It creates TD signal in ignition module. THis is not true in whell house unit. There rpm meter is directly connected to green primary ignition lead. I do not use the word Tachometer as that is very confusing and differently used in German and English. In German it means speedometer, in English rpm meter.