Cranks no start, no spark

Hi,

The first thing to check is if there is power the + on the coil. If there is and the coil is new, it could be the control unit. If there is no power, we need to trace it back to the ignition switch.

I attached a pic of the ignition switch below so you can see what I'm talking about.

Let me know what you find.

Joe

Hi,

Start by going to the ignition coil. There should be two wires connected to it in addition to the high tension wire. With the key on, you can use a test light or multi meter to see if there is power at the + terminal on the coil.

Let me know what you find.

Joe

Hi,

The negative of the meter can be put on any known ground, the body, engine, even the battery negative terminal if it can be reached. The positive on the meter will touch the + terminal on the coil. Don't crank the engine when you do this. It should have power just with the key on (run position).

Let me know what you find or if you have other questions. Don't be worried about asking. That's why I'm here. LOL

Take care,
Joe

Happy to help. Let me know the results.

Take care,
Joe

Hi,

Then the problem goes back to the ignition switch. That is the next place we need to check. Are you able to do that?

Let me know.
Joe

Hi,

Without testing, it is really hard to be sure. I wouldn't want to say replace it and then find that isn't the problem. There could be a break in the wiring between the two points and a new switch wouldn't fix that.

Let me know.
Joe

Before we move on to testing wiring, lets see if we can retrieve any diagnostic trouble codes. Here are the directions for getting them on this vehicle:

https://www.2carpros.com/articles/bmw-obd1-1995-and-earlier-code-definitions-and-retrieval-procedure

Let me know if you find anything.

Joe

Hi,

That sounds like a plan. I will watch for your reply.

Take care,
Joe

Hi,

Ironically, that code indicates no codes are stored.

That means we need to go to the ignition switch and see if there is power out from the switch. This means the switch will need removed to access the wiring. At the switch, you will check the wire with the same color as the one on the + side of the coil. It should get power when the key is in the on position.

To remove the switch is a little involved. I am going to provide the directions for replacement. Although you are not replacing the switch, the directions explain how to remove it and then install it. The attached pics correlate with the directions.

_______________________________

1991 BMW 735i (E32) L6-3430cc 3.4L SOHC (M30)
Ignition Switch Replacement
Vehicle Starting and Charging Sensors and Switches - Starting and Charging Ignition Switch Service and Repair Procedures Ignition Switch Replacement
IGNITION SWITCH REPLACEMENT
REPLACING IGNITION SWITCH:

- Disconnect ground lead (battery).
- Remove dashboard trim panel at bottom left.

Cars Without SRS:
- Remove steering wheel.

Pic 1

- Unscrew screws and take off lower and upper sections of the steering column casing.

Cars With SRS:

pic 2

- Unscrew screws and take off lower section of the steering column casing.

Pic 3

- Pull off plug (4).
- Cut off wire strap (5).
- Loosen holder (6).
- Lift out switch together with the wire harness.

Pic 4

- Press in retaining hooks on both sides and pull out the switch.

Installation:
- Check position of the ignition switch to the steering wheel lock.

_________________________________

Let me know if this is something you are comfortable with.

Joe

Hi,

SRS stands for supplemental restraint system (AKA Airbag).

Before you start working on it, disconnect the battery and wait for at least 30 minutes. And yes, the directions show it being done without removal.

Take your time. Let me know if I can help.

Joe