CSi suddenly dies

[sfdon]

Just to be clear- you drove the car with a warning light on for a year and a half?
Be glad it wasn't the oil pressure light.

 

[BMW3.0CSi]

Just to be clear- you drove the car with a warning light on for a year and a half?
Be glad it wasn't the oil pressure light.

To be honest, yes I did. I know which one is for the oil pressure But indeed, it took too long before I found out what it was and took to long before I really stepped into this issue. But after some years of rebuilding the car I lost my motivation a bit to solve again an issue that pops up after restoration, because for me the car was 'finished' after a few years of restoration work and I looked up to dismantle everything again because I initially thought that it was related to the wiring. Afterwards it's always easy to tell, but with doing my 2nd restoration on a 2800CS I learned my lessons...

I also knew where the warning light is ment for, but for some reason I printed the thought inside my head that with a fading bulb the issue was related to the battery loader when having the car in the garage for 2 or 3 months.

 

[BMW3.0CSi]

It is very common for the three wires from regulator to battery to became frayed, lose their sheathing and come into contact as they are somewhat hidden. If the charging lamp stays on your system is not charging. Your loose wire is the culprit here. To test the alternator run the motor and put your voltmeter on the battery posts, you should see around 14V. With motor off around 12V. If you replace your alternator with a modern single wire model you can run the blue wire directly to the alternator and bypass the regulator with its three wires entirely. Leave the regulator in place with no wires attached to keep a period look.

Chris, is it correct that from the 3 blue wires that you see in the picture of the plug on the regulator, you run the top right one in the picture to the alternator and leave the other two? If I'm correct those two run back and forth between the altenator and regulator?

 

[HB Chris]

The blue wire in the chassis harness that goes to the regulator gets extended to the Alternator D+ terminal instead, the other wires are removed.

 

[BMW3.0CSi]

I kept everything 'original', I renewed the wires, put in a new Hella external voltage regulator and brought the dynamo to a specialized company to let it be checked on correct functioning. It appeared that the rotor had an internal short, we replaced the rotor with a rotor of a second (old) dynamo I had. Dynamo is now ok again, and after starting the car with everything new the dashboard light is also gone..
So after all I can explain most of the issues I had based on whats now fixed. Coil is now also at normal temperature, while I haven't been driving the car, just a idle test. I need to wait for better weather

I hope that my initial issue of a hampering engine between 1.5-3k rev's at idle speed is maybe also solved. Some other threads, here and on other forums, point towards the coil and external resistor. Only thing is that this is already going on before this issue, but in the meanwhile I also renewed the coil. We will see after the first test drive.

 

[BMW3.0CSi]

Finally I can comment here that I have found my issue, it is a little bit painful and shameful so to say....
I bought myself the simplest AUTOOL smoker for leak checking and with this I found my problem, it appeared to be that I had a missing gasket on 1 of the air intake tubes, have actually no idea when that happened, but must have overlooked it... In the picture of the tube I have placed the gasket already, it was the lower gasket from the intake tube were the bracket of the cold start air intake valve is attached to.
What I also found during the smoke test (10-15psi pressure) was that the throttle valve housing was leaking on both sides were the axis of the throttle valve goes through the housing. Need to see what to do with that, new bushes are not available to what I see on W&N and BMW Classic.

Looking back to what I have checked and done over time it was to my opinion the combination of this, an old coil, maybe the ignition pulse indicator and the failing alternator of course which gave a short to my voltage regulator and in the end a low voltage battery.

After the first kilometers test driving I could finally concluded that it is solved, quit a relief!

 

[Roman596061]

Hi all,

I need some help or general thoughts about the issue I have with my CSi. I few weeks ago I finally was in the position after 2.5 years of work to really drive the car.
After driving for almost 200kms the car suddenly died on the highway. At a speed of 120km/h the car struggled and finally stopped. With 3 or 4 big bangs from under the hood I managed to get the car safely on the side of the highway. Because of the 'bangs' I thought something really damaged but after opening the roof everything looked normal, nothing to see.
I then tried to restart the car, but the startmotor went very slow, as if you have a low battery. At that moment I thought about something in the engine itself (hardware).
Called the tow company, brought me home, and after 3 hours the car was in my garage again. Couldn't resist to try to start it again and it actually didn't, as if nothing happened.

After reviewing what happened, I now think/know that I lost ignition, gas kept on going, which came into the exhaust manifolds (self ignition because of the heat) and after the car cooled down it started again. I didn't felt on the coil, if it was hot or not. With trying to find something on the forum I came across this threat: https://e9coupe.com/forum/threads/smokin-hot-ballast-resistor.9504/
But I don't oversee the whole picture, I have a new coil, new contact breaker points, new plugs & wires, new distributor, new rotor, new injection trigger points but an old resistor and the original wiring (which I suspect, while it all looks ok).

Any thoughts? Thanks for help.

Read this link - https://bimmerlife.com/2020/08/29/nailing-the-e9s-electrical-issue/