1990 K75s not starting

[wayside]

rbm, all I have is Bert's troubleshooting paper. I have Identified FI relay, just to be clear Im testing correctly on pin 86 I check that by pulling the relay and test the 86 slot that the relay plugs into?

[rbm]

Probably better to remove the screw securing the relay socket and test from the bottom of the socket.

[wayside]

Nothing on 87 or 87a, everything else checked out. If I'm doing it correctly!

[wayside]

Bad relay?

[rbm]

So from the schematic, pin 30 on the FI relay is fed from the battery positive terminal directly.  If you measure 12V on the red wire into the FI relay, and no voltage is measured on the output pins, the relay is defective.

[wayside]

Thanks for the help Robert, Ill get a relay on order! Great forum, no way I could have done this with out it.

Bill

[The Mighty Gryphon]

No need to order from BMW.  Take your old relay to the local discount auto parts store and have them match it.  You'll have a new one in your hand tomorrow for around 15 bucks.

[rbm]

Jim,  The FI relay is special.  It is not a typical off-the-shelf automotive SPDT relay, the FI relay is a DPST.  If you're lucky your supplier might find a Fiamm horn relay with that configuration -- extremely lucky.

Bill, before you write-off the relay, do a bench test on it to confirm that it is defective.  Remove it from the socket.  Apply 12V to the 85/86 pins and measure continuity on any or both of the 87/30 pin pairs.  When you activate the coil with the 12V, the meter should read 0 ohms (or very close to it).  With no 12V applied to the coil, the resistance should be infinite (open circuit).  if this simple bench test works, you might be following a false lead.  It could be the socket connections need cleaning, for example.  On the other hand, if the bench test shows that there is open circuit between 30/87 pins even with power applied to the coil, this is conclusive proof of a defective relay.

[wayside]

Robert, going to need a little direction on how accomplish this.

thanks.