Relay Identification; Purpose; Part Numbers?

[mdsalemi]

All the time: something new.  My car has worked for 10 years w/o these parts so I suspect they are unnecessary, but nonetheless would like to find out what they are; what they do; and part numbers if possible.

It is a set of two relays, one larger, one smaller.  I suspect it has something to do with some kind of emissions, but that's just a guess.

I believe it was Tom Collitt who discovered them missing on my car at PUB; I went back to my original photos and sure enough they were there.  Somehow the restorer saw fit not to replace them.

These are the relays in the photos.  One photo is an original from my car in the year 1999 prior to restoration; the other was taken at PUB.

I do indeed appear to have the wires with ends that plug into this assembly, tucked away and unused.

[69280sl]

Michael:

On my 1968, the smaller relay has Bosch # 0332 202 001. The larger does not have a visible #. Maybe on the underside?
Hope someone can advise the function of these relays. I havn't a clue.

Gus

[Naj ✝︎]

I believe these relays are the early version of the emissions control system. Some late 250 Sls have them too.
The smaller relay controls the vacuum retard valve.
The bigger one I beleive is the speed sensor.
Question is: do your inj pumps have one or two solenoids at the back? A second solenoid was added to cut off fuel supply under decelaration.

In my opinion, Michael's restorer was smart not to refit them, But I think I'm in the minority with that opinion... 

Naj

[mdsalemi]

Naj, my injector pump has BOTH relays, but we disconnected the bottom relay.

The car runs fine w/o it but would be nice to make the engine bay at least look complete!

[66andBlue]

... I do indeed appear to have the wires with ends that plug into this assembly, tucked away and unused.

Michael,
in addition to the wires you also need to find the bracket that holds the relays and then feed the wires back along the main harness to a switch on the firewall that controls the deceleration.
During the engine rebuilt in  my 280SL Joe A. removed the relays, the switch, and when the FIP was rebuilt by Gus at Pacific Fuel Injection the lower relay was also removed and the opening covered with a plate.
As Joe explained to me when that switch fails - the only thing you can do is call a flatbed toe truck. Your restorer was indeed a smart man.

[Naj ✝︎]

OK, all the relays are on page 3 in section 54 of the EPC.

Naj

[mdsalemi]

Alfred,

Thanks so much...which relay on the firewall?  I think your photo was simply of the same relay set I'm seeking.

Don't be alarmed, would be for appearance sake only.  Car is running very well, at least it was when put away for hibernation, that I dare not mess with it--just trying to make it more complete.

Like the condenser on the side of my -051 which isn't used, nor the ballast resistor either.  But they are present and look nice! 

Perhaps someone has the full discarded set and I'll find that...

[66andBlue]

No relay on the firewall but a switch!
Yes, my photo shows the same relays as yours but it also shows the bracket and how you need to connect some other wires for the "authentic look". 
I'll post a photo of the switch later after verification from Joe that I picked the correct one.

[mdsalemi]

Got it Alfred, see PM.

I have all the parts BUT the relays...switch is mounted; I have the bracket (file that under, "Oh, so THAT'S what that metal plate is!!!") sitting in a box of parts.  Just need to get the relays for authentic look.

[wwheeler]

I think this schematic might be for the system that Michael is referring to. It prevents backfire during deacceleration and uses the lower fuel shut off solenoid on the FIP. The system can malfunction causing the solenoid to permanetly engage the shut off solenoid leaving you w/o fuel from the FIP.

My US '68 W111 has this and it still works (for now).

[ja17]

Hello Michael,

I have good documentation of what goes where and  I made a good schematic of the separate wiring harness. Let me know what info you need.