Need some help diagnosing problems on new Bimmer

[ItsRosco]

Hello everyone, I am new to building cars and have always loved the 90s BMW look.


I just bought a 1993 E34 525i that appeared to be in decent enough shape. I am now experiencing some issues that are hard to pin point since we can't use OBD2 scanners.

To start, the gear indicator light disappears shortly after turning on the ignition. It will then start in what I believe is limp mode? When I drive after starting like this the shifting seems very slow and not great. If I turn the key one click before ignition and wait 5-10 seconds, sometimes the gear indicator light will stay on and the car will start normally. I'm not really sure what to make of this.

The second thing I have started to notice is that the car starts to shake a bit when in idle. This rattling does go away once I start driving however; it's only when I'm stopped and idling. The CEL just recently came on, and after doing the stomp test it gave the 1222 code, which appears to be the o2 sensor. Could this be related?

The third thing is I seem to be leaking power steering fluid. How would I go about finding where the leak is?

I appreciate any help!

[dannyzabolotny]

The transmission issue could be a gear position switch, but it's hard to tell without talking to the transmission control unit. Yes, it's OBDI but some versions of ISTA and some old scanners are able to communicate with it, like the Peake reader.

The second thing is a vacuum leak, pretty common on M50's. That's why it shakes at idle and has the CEL for a fuel mixture issue. Replace the intake manifold gaskets, the vacuum lines under the intake, and the intake boots, those are the most common causes of vacuum leaks on an M50.

Power steering fluid leaks come from most of the power steering hoses, they start out as a seep and then get worse over time. A set of OEM power steering hoses is not terribly expensive, and access to replace them is quite good on an M50 car, so I would advise just knocking them all out at once. One thing I will say is to make sure it's your power steering leaking and not the transmission cooler lines... both use ATF and run in similar spots on the driver's side of the engine bay.