Ignition timing & auto box relays

[Savakis]

Hello,

I am showing here 2 pictures of 2 different cars.

(1) Would anybody help to identify the 2 relays of the red car pictured here? (see attached photo).

I suppose they are the ignition timing & auto box relays -correct?

This picture comes from a friend's car which I borrowed to sort things out (a red 1969 280SL auto, US version).

(2) My car's engine bay is shown in the second picture (a US version 1970 280SL auto with a refurbished M130.983 Euro engine).

As can be seen in the second photo showing my car, there are 2 wires with a 6-pin and 8-pin connectors, respectively.

I guess I need to find 2 relays -just like the ones pictured in the red car's photo.

Are there any relay suppliers or W113 parts suppliers in Europe or the US that would carry these relays?

Thanks in advance for any piece of information.

[dirkbalter]

Depending on what was done to your car when the engine was refurbished, the relays may have been removed. These relays due to their age are often faulty and not really needed unless you want to maintain the questionable emissions upgrade to the US versions. As mentioned before, it all depends on what was done to your engine set up.

[WRe]

https://www.sl113.org/wiki/Electrical/EmissionControlSystem

[lpeterssen]

Hello my friend

I recently produced for another member a totally new emissions control harness with success.

If you are in need for one that resembles the original design without any mod, I am available

Best regards
Eng Leo Peterssen
Wwww.wiredoktor.com

[Savakis]

Hello and thanks for your answer.

The harness has been installed, the engine starts and revs -it seems that the 2 cables are ready to be plugged into a set of relays.

My mechanic says that according to the W113 electrics diagram, the fuel pump and the throttle mechanism interconnect with these 2 relays.

Can you help with sourcing the relays?

Regards,
Savvas

[lpeterssen]

Dear Savakis

No unfortunately I do not have any of those specialized relays. Their functionality is to determine if fuel can be shutoff in order to reduce pollution.  You need one part that is called speed relay which monitors as its name says the engine RPM via a lead to the negative post of the ignition coil. That information in conjunction with the signals sent by the IDDLE switch at intake manifold, the low pressure switch at the automatic transmission and the position of your transmission lever let an early ECU (basic computer based on relays) decide if the fuel can be shutoff at the injection pump.

So you can live without this system.  But if you want to restore its functionality apart from sourcing the speed relay and the relay box you need To carefully inspect the condition of this particular harness so that it works as designed.

Best regards
Eng. Leonardo Peterssen
Www.Wiredoktor.com

[Savakis]

I appreciate the detailed explanation!

[dirkbalter]

These relays are not easy to find. If you find them, they tend to be expensive and you don't know if they work correctly until they are installed. You say you have an European M 130 installed. What does that mean? The wiring harness you have, will work without the relays. The components that need change, assuming you have the original ones, are the throttle body and the distributor. Thats why I was asking. In addition to the relays, you will also have to install a vacuum shut off valve as described in our tech manual.
(I went thru this with my 108.)   

[lpeterssen]

I totally agree with Dirk.

The emission harness is a separated component, you can simply remove it by unscrewing the feed T15 from main fuse box, terminal 5. And then the complete harness is separated from the main harness.  There is nothing to be chopped. To run the emission harness you need to have ALL the correct components.

The other place where it should be disconnected to have it free is the terminal block at the automatic transmission.  It takes IDDLE an low transmission pressure signals at that place.

Best regards
L.Peterssen

[lpeterssen]

And if finally you have an European M130 engine, then most probably your Fuel injection Pump does not have on the back the Fuel shut off selenoid, then makes no sense to have a emission control wiring harness in place since it would not do anything.

[Savakis]

Thanks again for your useful tips!

Regards,
Savvas

[Savakis]

Thanks for your response.