Electrical nightmare and I am out of ideas

[Panici]

It was the wildest thing!
...
I pulled most of the wiring out and tested lead by lead from the tail lights.

Good troubleshooting skills. Something people don't know how to do anymore!

while looking for the issue replaced the entire clutch system. master, slave, hard line, both flex line.

On the plus side, your entire clutch system is now fresh!

[cyrillink]

3rd brake light eh? Wouldn't have guessed that one.
I guess your hunch about something in the back of the car was correct.

It was the wildest thing!
When the car was off, no batt in the terminal.
I would do a OHM or close circuit test (beeping) on the multimeter it would ring.
when i pulled the disconnected everything in the engine bay, the beeping was still going on.
Then I pulled relays, nothing would change.
Only when 6 8 10 were pulled i would get a drop, and it would stop beeping.
I wish i noticed the 3 prong clip for the 3rd brake earlier.
I pulled most of the wiring out and tested lead by lead from the tail lights.

Have a new issue, but i discovered the fix for it. also kinda stupid tbh.
My brake line going to the back needs to be changed. while looking for the issue replaced the entire clutch system. master, slave, hard line, both flex line.

[cyrillink]

Not sure if you're aware of this site, but you can grab the Electrical Troubleshooting Manual for your car/year, which REALLY helps with troubleshooting:

http://www.wedophones.com/BMWManualsLead.htm

Save a copy in case the site dissapears.

Appreciate it, I just saved it.
Going old skool lol, go to fedex and printing it.
Thank you!

[Panici]

You guys are going to laugh....
3rd brake light.
I disconnected it. Short went away.
Connected all the cables. started right up.
WTF is going on with the 3rd light!
anyways, We are done!
Have some housekeeping to do first. Mission for 2022 complete.
Thank you for all the help team

3rd brake light eh? Wouldn't have guessed that one.
I guess your hunch about something in the back of the car was correct.

[McGyver]

Not sure if you're aware of this site, but you can grab the Electrical Troubleshooting Manual for your car/year, which REALLY helps with troubleshooting:

http://www.wedophones.com/BMWManualsLead.htm

Save a copy in case the site dissapears.

[cyrillink]

You guys are going to laugh....
3rd brake light.
I disconnected it. Short went away.
Connected all the cables. started right up.
WTF is going on with the 3rd light!
anyways, We are done!
Have some housekeeping to do first. Mission for 2022 complete.
Thank you for all the help team

[cyrillink]

My car is newer than yours and modified, a '91 318is with a '91 325i convertible engine and harness in it, but this is what I have:



Ignore the white wire on the top terminal in picture two, it's an add-on. There are no wires going to my valve cover, It has been too long since I looked at a stock car to recall if there are supposed to be any.

I will send a picture of that i have on the positive and negative terminal in a few. cleaning up. I have strong suspicion it something in the back of the car.
When i pull fuse 6 ohm drop to from1.3 - 34 ohms
and when i pull 8 goes to 44 ohm

[cyrillink]

I'll echo the question Mr. Burgandy raised. This issue is not what the CPS reads but whether you plugged the CPS in correctly. There are two connectors side by side that look exactly the same. Swap them and see what happens. Easy to do and rules this out. I made this mistake once when trying to trace a no start (with no spark and no fuel after testing all other options). My old CPS would read fine but had a wire short where the insulation had worn through. I replaced the CPS with a new one and connected everything back up and still no start. Just on a hunch I swapped the plug connections since I had been moving things around and forgotten to mark which connectors went with which plugs. Car fired right up.

When i took the car apart originally i marked up identical cables with different color masking tape to ensure i connect those back up.
just for kicks, i swapped them and tried again.
Relay still buzzing not spark no fuel.
I think there is a short something rubbed throw or cut a positive.

[It's Soda Not Pop]

Look into the 13 button OBC. I know it can cause problems.

https://www.r3vlimited.com/board/forum/e30-technical-forums/general-technical/49808-obc-immobilizer-bypass

[Boris3]

I'll echo the question Mr. Burgandy raised. This issue is not what the CPS reads but whether you plugged the CPS in correctly. There are two connectors side by side that look exactly the same. Swap them and see what happens. Easy to do and rules this out. I made this mistake once when trying to trace a no start (with no spark and no fuel after testing all other options). My old CPS would read fine but had a wire short where the insulation had worn through. I replaced the CPS with a new one and connected everything back up and still no start. Just on a hunch I swapped the plug connections since I had been moving things around and forgotten to mark which connectors went with which plugs. Car fired right up.

[varg]

My car is newer than yours and modified, a '91 318is with a '91 325i convertible engine and harness in it, but this is what I have:



Ignore the white wire on the top terminal in picture two, it's an add-on. There are no wires going to my valve cover, It has been too long since I looked at a stock car to recall if there are supposed to be any.

[cyrillink]

If you think you have a short check the strut tower grounds and positive wires on the firewall distribution block. They are long enough to be swapped and BMW used brown for ground and black for positive, which confuses people. One of those wires being swapped can cause a buzzing relay, I have seen it before, another burns the harness up.

This is interesting. I am going to check that in an hour or so.
I believe I have 3or4 wires coming into the positive terminal red w/black shielding.
1 Negative going straight to the tower. and then i have a wrapped bundle of black from the firewall which is connected to the valve cover.

[cyrillink]

What have you replaced relay wise? did you do a fuel pump replacement? If so which pump did you use? Are all your grounds good? What codes are showing during a stomp test? Could be your ignition switch going bad. Do you have a 13 button OBC? if so it might cutting fuel because of the disable code.

1. Relays - I pulled out all the relays looking for the short
2. No Fuel pump works well when you short 30/87 on the middle relay
3. All Grounds have been cleaned and seem good according to the multi meter.
4. Could be your ignition switch going bad - i didnt know they go bad, do they have a ground in them that could short? and cause a buzzing relay?
5. 13 button OBC - yes i have. Have not checked it because there is a short through out the system.

[varg]

If you think you have a short check the strut tower grounds and positive wires on the firewall distribution block. They are long enough to be swapped and BMW used brown for ground and black for positive, which confuses people. One of those wires being swapped can cause a buzzing relay, I have seen it before, another burns the harness up.

[It's Soda Not Pop]

What have you replaced relay wise? did you do a fuel pump replacement? If so which pump did you use? Are all your grounds good? What codes are showing during a stomp test? Could be your ignition switch going bad. Do you have a 13 button OBC? if so it might cutting fuel because of the disable code.