Please help me identify what is missing

[Zekiguy123]

Hey everyone. I am currently trying to diagnose my recently purchased 1990 525i with an m20b25 which will crank but wont start. I'm 90% sure it has to do with the crankshaft position sensor, so I watched a few YouTube videos on what to do to try and replace the sensor.

While watching videos, I noticed I am completely missing a circular tube and some connection points underneath it. Attached is a picture of my car and a screenshot from a YouTube video (the photo with red text) which show the differences in the two images.

Could anybody possibly help me identify what I am missing in my car? Thanks a lot!!

https://imgur.com/a/zs018AC

[Sir Montalbon]

Hey everyone. I am currently trying to diagnose my recently purchased 1990 525i with an m20b25 which will crank but wont start. I'm 90% sure it has to do with the crankshaft position sensor, so I watched a few YouTube videos on what to do to try and replace the sensor.

While watching videos, I noticed I am completely missing a circular tube and some connection points underneath it. Attached is a picture of my car and a screenshot from a YouTube video (the photo with red text) which show the differences in the two images.

Could anybody possibly help me identify what I am missing in my car? Thanks a lot!!

https://imgur.com/a/zs018AC

I don't have much experience with your engine, so I can't help much more than to tell you that the circular connector is the 20pin OBD I port for connecting a diagnostic computer.

Maybe someone else can chime in as to why it is missing.

[ross1]

"circular tube"? The round item above the red arrow? That is the 20 pin diagnostic port and, if that is an E34 engine bay, in the wrong spot. I'll bet that is an E30 engine shown in that pic. Your diagnostic port should be on the shock tower near the brake booster. Look there on your car there for it.
As for the connector(s) the arrow points to it is either for the crankshaft position sensor or the cylinder identification wire. I believe yours will be placed a bit differently but still near that area in the pics., aft and below the the thermostat as I recall. The two connectors will still be side by side. It's been a loong time since I've touched an M20

[Zekiguy123]

Thank you for the help Ross. I didn't realize the engine configuration for the m20b25 found on e30s and e34s would be different! I was able to find the area to plug in the crank position sensor.

[shogun]

in such a case go to the ETM of your built year, at the end there are component location charts and component location views, that shows you exactly what is where, which position number it has etc https://shark.armchair.mb.ca/~dave/BMW/e34/