Hi Dave!
What an exellent picture! A customer would be very pleased to see such a pic in an issue investigation and pay for it gladly. However, I must admit I was wrong here after checking the relay connector 87b on the wiring scheme. 87b is the same as number 4 wich goes to..........the FUEL PUMP and SUPPLEMENTARY AIR VALVE!!! Iīm relly surprised!
But if you think of it, the fuel pump has to be a great inductive load too to the relay contacts. Air valve coil my add some load as well (or is it just electrically heathed to open) . I donīt have any figures on the amperage these objects have in action but fuse 2 is
16 Amp!!!!!For not breaking the fuse in the long run, current could perhaps be around 12-14 Amps and that will make a good spark over contact 87b and 30 (2 & 4) when engine is stopped. Well, it is obvious that inductive load is not good for relays and should be dampened in some way. Maybe Ferdinand thought a lifespan of 17 - 20 years for our 944s would be enough, so he wasnīt worried about any relays in the car LOL.
Reminds me, did you push on that relay yoke to see if it could move freely down to the coil before you dismantled it? The two wires (now cut) seem too short in the first picture to allow that. That could also be an issue cause the contact force would be limited and contacts would start arcing when engine is running!
So, to your next question. Not beeing an electronic engineer (just electric) I think a capacitor over the relay pin 87b (4) and ground 85 (1) will do and with values of 0.47 microFarad, 200 Volt....an example taken from an old distributor with breaker.
(I compare the primary coil current in an ignition coil with the fuel pump current here).
A conclusion of all this mumbling of me would be a capacitor from relay pin 87b (4) to chassi ground and while in there why not connect a capacitor from pin 87 (8) and chassi ground as well. If those capacitors could be mounted behind the relay plate, one could use the original relay and live with it forever......perhaps.
I will try this in my experiments as soon as possible and let you know.
________________________________________________
Lapponia 1984 944 na