<E28> "no spark" condition solved

["Jon E. Streiff, D.C." <drjon@xxxxxxxx>]

I would like to thank all the people who helped me resolve the "no
spark" condition in my 84 533i. The cause was something I have not seen
mentioned before on this list though. So by posting this, maybe I can
help some other poor Bimwad resolve his "no spark" problem.

What ended up causing the whole mess, was when I inadvertantly reversed
the main and fuel pump relays. They both have the same orientation of
the terminals, so they are interchangeable right. WRONG! The fuel pump
relay (on my vehicle at least) looks like the main relay, but actually,
pins 30 and 86 are reversed. Normally, the wire from the ignition switch
to the master relay only energizes that relay, using very little
current. With the relays switched around, that wire now supplies 12V to
the fuel pump, fuel injectors, purge valve relay and ECU. This wire also
goes thru a solid state relay in the On Board Computer so the anti-theft
feature can prevent the vehicle from starting if necessary. This relay
was not designed for that amount of current, and, in my case, fried. I
"fixed" it by jumping pins 14 & 15 on the OBC, thus bypassing the solid
state relay(and eliminating the anti-theft feature). 

I found this problem by checking the voltage at terminal 86 of the main
relay. With the key on, it should read 12V. I was getting only 1.5V. Not
enough to energize the the main relay.

Hope this helps someone.

Jon Streiff
72 2002
84 533i

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