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Lapis 635 Euro
11-05-2011, 07:02 PM
Continuing my saga of crank but no start issues on my '84 635CSi Euro with OBC version 1. Tried the procedure listed here today: http://pwp.att.net/p/s/community.dll?ep=87&subpageid=110934&ck= to see if jumping the OBC relay would solve the issue. I didn't have any luck with the step of the instructions that stated to remove, add a jump wire, then reinstall the Green and Green/Red wires from the harness. They seemed like they would tear if I kept pulling on them any harder. I still was able to apply a small jumper wire (shown in the pic below in ORANGE) between the two terminals by wedging it between the two terminals. The car still does not start. The OBC continues to function as normal otherwise, which it always has. I just feel my method is a bit inconclusive before I move on to trying something else. Has anyone else successfully performed this fix on an OBC 1 and did it get your shark running again?

Some other information from prior steps I've completed: Car does not get spark. Coil, main relay, fuel pump relay, main fuel pump, spark plugs/wires, cap/rotor, and reference sensor are either brand new or new within the last year. A spare ECU has been swapped as well. Any other ideas for things to test/try? Thanks for any assistance.

https://lh3.googleusercontent.com/-Zhz-tQFcmiQ/TrW-sBaFA_I/AAAAAAAABMM/7ESve7kY-dw/s512/IMAG0353.jpg
SUABBYM6
11-05-2011, 08:27 PM
Not 100% familiar w/ your system, but, if there is an OBC relay box(located stacked L of my 87 M6 steering column) after 2+ years of intermittant no start, I finally found a bad connection in the plug on the OBC relay box. That's my 2cents, otherwise break out the big hammer. Good luck.
CW6er
11-05-2011, 09:57 PM
Here is how to check the OBC Relay:
Pull the Main relay and with the key on, check for voltage in socket 86 in the relay holder (the numbers are molded into the bottom of the relay). If there is voltage, then the OBC relay is good.
amcink
06-08-2012, 01:05 PM
Here is how to check the OBC Relay:
Pull the Main relay and with the key on, check for voltage in socket 86 in the relay holder (the numbers are molded into the bottom of the relay). If there is voltage, then the OBC relay is good.

How can I do this?