No start ‘89 325i

[Marle30]

Recently inherited my daughter’s ‘89 convertible.
With no warning, it will not start. New main relay, new fuel pump relay, new fuel pump. Been diagnosing the problem - no 12volt at coil +15, checked ignition switch, now have jumped green wires at ecu relay, and have 12 volts at coil. I believe it is a failed ecu relay. Question for those who have dealt with this relay, does it also control the injectors and fuel pump? Fuel pump works when relay is jumped, but still will not start. Thanks!

[ButtJuice]

Check fuses? 🤷

[Marle30]

All fuses have been checked. Thanks!

[RobDog]

Does the replacement main relay have 2 pin 87’s and not an 87/87a configuration? The main relay is unique and turns on power to 2 pins (87/87) at the same time, where as a standard relay switches power between 2 pins (87/87a). If you have the wrong relay the car will not start because only one pin will be getting power, so only half the engine electronics will be getting power.

[george graves]

^good post.

[Marle30]

Slow to reply - apologies and thank you for the suggestion. The new main relay is genuine BMW and the correct configuration. I will check for power at both 87 pins. The relay only has about 250 miles - but nothing surprises me with electrical failures...

[RobDog]

Maybe the OBC relay has went bad and preventing the car from starting? It’s common for these cars, especially since they are getting old and the electronics are starting to fail. Here is how to bypass the OBC relay. Under the drivers kick panel, behind the abs computer(big shinny silver box), is a smaller rectangular black box with 2 green connectors. The connectors look like the door chime connectors but green. In those 2 green connectors there are about 6 wires. The 2 largest wires are green and green/red. Cut the green and green/red wires, then splice them together to bypass the obc relay.

[Marle30]

I have bypassed the obc relay green wires, and have power to the coil. Prior to jumping the green and green/red wire there wasn’t power to the coil. With the relay bypassed the starter turns over, but still won’t start. Waiting for the obc relay to arrive. Hopefully this will work.
Thank You for your suggestions 👍

[Marle30]

Received the ”obc relay” and installed it. Still no start (sigh...). Will try searching/checking the fusible link and proceed from there.

[325e '87]

damn that sucks. I’m watching. My ‘89 is ok but these posts keep me up at night....

[skitzy777]

check this, http://www.e30zone.net/e30zonewiki/i...s_Troubleshoot

[Marle30]

Didn’t want to leave this thread unfinished. Finally solved the problem(s) with not starting. The replaced fuel pump was faulty along with the computer. Changed both out and now the car runs great! Nothing like two faulty parts to really make diagnosing a problem difficult...
Now on to other projects on the car. Next up will be new window seals and chasing a tiny coolant leak and the oil pan gasket.
Thanks for the suggestions and cheers!

[bankrupt]

How did you determine the new pump was bad and especially the cpu? Mi 1091 Ix won’t start suddenly. Already changed pump, it only ran for a day. Changed coil, no luck.