Help! I am about to give up on my R107 350SL

Hi James, hi Volker,
does the M116 wiring harness (or this car...) have a connection from lead 12 to the ground at TPS or somewhere else? I believe the M116 doesn't have this in original, but other cars have...
Maybe someone made such a connection to make a better ground connection for the D-Jet-system.

This then could be the reason for the damage: Bad earth from chassis to engine. When high current flows (esp. when starting) insufficient engine-earth would cause such a damage - engine would try to 'get' earth via the grounded (at the engine) lead 12 and the grounded lead 11 (grounded at the chassis).

Just an idea

Norbert

Hi Volker,

Sigh, yes it is severe, and this is only maybe 10% of the issues I have faced so far elsewhere in the car...

I have conveyed your instructions to my mechanic. I am ordering a refurbished ECU from Australia. The workshop is fixing the wiring harness - can you explain further what you mean by swap 2 contacts in the connector housing?

How shall I send you the ECU?

And yes, my mechanic opened the ECU out of desperation, as he could not trace to any other issues already.

Norbert - I have no idea actually whether lead 12 has a ground or not. I am totally not technically inclined, this is all very difficult to understand for me.

Hi Volker,

An additional question from my mechanic - is this existing injector on the car correct for the 350SL?

Cheers,

James

Hi James,
two answers I can give, too.
- This injector isn't an original one. It's similar only, has the same fit. A type 'EV1' injector, manufacturer and type unknown..
Maybe it fits - one had to compare impedance and the flow tables.
But maybe it's totally wrong... try to find out the make / type.

---

Your workshop can easily check out the possible problem I described before.
They can check both damaged wires for continuity towards the chassis (ground)).
One (PIN 11) has to be resistance of 0 Ohm towards the chassis - it is the ground wire.
The other one (PIN 12) has to be isolated from the ground, endless resistance towards the ground.

Regards
Norbert

Hi James,

those are the wrong injectors, they look like L-Jetronic injectors. You need yellow D-Jetronic injectors and they are hard to find. If you find nothing in Signapore, I should still have new ones.

The 2 contacts in connector housing to ECU are very special, not normal receptacles. I've recently managed to get hold of some after hunting every Bosch service and other workshops for years. That is why I recommend you to replace these 2 burnt contacts. If the fail temporarily you will have no injection.

You need to find the reason for the wiring harness or workshop failure. If you look at chapter 10 of my compendium , you can find all necessary material for rebuilding a wiring harness.

Thank you both!

I'm shocked to find out that my injector is non-original, but because replacements are so expensive and hard to come by I think I will stick with the current ones for now. After all, my car did seem to run fine for a while with the current injectors.
I suspect my current ones are for the 450SL, but I am not sure. There is no make or type indication on the injector.

As for Pin 11 and 12, strangely the workshop checked and their grounding is correct, there is no issue with them. I wonder what else could have caused the burning? I fear, could it be water leaking and therefore causing a short circuit? I did not show it on this forum before, but my ICU was actually found to be completely drenched before, with water inside. I have since replaced it.

So far I have already replaced a water pump, fuel pump, distributor cap, rotor button, trigger points, distributor, ICU, air temp sensor and throttle valve switch.