BMW 1 Series Issues: Troubleshooting & Fixes

Hello,

My Z1 seems to be having some issues; I think it's about to give up. I have a lot of error codes in the diagnostic memory.

539 Donors Fuel Temperature.
30 KS after + static.
Okay, I can get rid of that with a new MSW (Microsoft Software License) that I still have.

777 Accelerator pedal position sensor (G79).
156 horsepower after modification + occasional issues.
'If the device fails, it should actually switch to emergency mode, right? That hasn't happened yet. According to the diagnosis, the sensor is also working properly.'

519 Donors Intake Manifold Pressure G71.
156 horsepower after modification + occasional issues.
The intake manifold pressure is also within the normal range when I run a diagnostic check, so it's within the specified parameters. That's strange!

741 Brake pedal monitoring.
155 implausible signals sporadically.
No idea. The brakes are working, and the brake lights are also on!

1117 Load Signal Generator Terminal DF.
27 implausible signal static.
I once swapped the starter motor for one with a freewheel clutch. It's possible that the DF signal isn't the same, but I don't know why.

'Definitely, with these issues, I can't maintain a consistent speed; it feels like the engine momentarily cuts out of fuel intermittently, every few seconds.'

Once the software bugs are fixed, it should work again. But it's strange because the things aren't actually broken. I have no idea what's going on???

You can ignore the 1117.
I have all of those as well, because I once had them installed. I have no idea where they come from or what they do, because I don't notice any difference whether they are in the memory or not.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

I once heard that the DF signal is used to slightly increase the fuel injection amount so that the alternator can produce more power when many consumers are turned on in winter. I hope I haven't misunderstood anything.

Cabriodriver wrote:

.... If the

sporadic errors are gone, it will work again. But it's strange that the things aren't actually broken. I have no idea what's going on???https://community.dieselschrauber.org/en/viewtopic.php?t=12414&highlight=kurzschluss+nach+plus

Nachdenken ist Glücksache ... Or what?

What does "Kuzschluss nach Plus" mean?
If you've found this answer, it should be clear where you need to look for more information.

All your mistakes can clearly be traced back to the same root cause.


EDIT: you would have found this here }, under the search function.

Well, electricity isn't really my strong suit, sorry. I would be very grateful if you could help me. That's what this forum is for, right?

I've used the search function and already read the relevant threads. However, I'm not sure if that applies to my situation. You seem very confident, but I'm not. And here's why:

If I understand correctly, are you suggesting that the problem is due to a missing ground connection, which is caused by a blown fuse or damaged grounding wire in the engine control unit? (I haven't installed any tuning boxes or made any other modifications to the engine.)

But first: the fuel temperature sensor is definitely defective; I know this because it's been faulty for a while.

Secondly, the sensors for the accelerator pedal and intake manifold pressure, as well as the brake pedal monitoring system, are only intermittently present and not consistently displayed, and when they do appear, the values are different. I regularly check the error memory. How is this possible? Could it be a loose connection? Or could it just happen suddenly?

Cabriodriver wrote:

... If I understand correctly, are you suggesting that the problem is a lack of mass...?

Sure.

Quote:

... which is due to the engine control unit...

NO!

Not necessarily. A mass error on the engine control unit (ECU) or the engine block can also produce the same error code.

As mentioned in the thread above:
Try measuring the ground mass in the engine wiring harness first. A broken wire within it could have the same effect as a burnt-out circuit trace.

Quote:

But first: the fuel temperature sensor is definitely defective; I know this because it's been faulty for a while.

I don't think so...

Quote:

Secondly: the sensors for the accelerator pedal and intake manifold pressure, as well as the brake pedal monitoring system, are only intermittently present and not static, and also vary in their readings. I regularly check the error memory. How can this be? Is it a loose connection? Could it just happen suddenly?

Genau .... All of a sudden, like that!

I always used to say to my relatives: "Yesterday, Grandma was still alive, and today we are carrying her to her grave."
Even though it sounds macabre, that's just the way it is.

Aber nun mal zu deinem Fehler. Das dein Kraftstofftemperaturegeber defekt ist bezweifle ich mal. Zu 75% hast du schon länger ein Problem mit der Masse am Motorblock oder mit der Verbindung Masse->STG. Durch ein undefiniertes Massepotential kann die Temperatur im MSTG nicht korrekt gemessen werden und der Geber wird als defekt gemeldet. Übergangswiderstände (durch z.B. Wassereinbruch) kommen schleichend und führen dann zunächst zum Zeitweisen, dann aber zum schalgartigen Ausfall. GenSame here.

Simply put, you're currently experiencing an intermittent connection issue (somewhere in the wiring harness... especially the ground connection).

"Please provide the text you would like me to translate from German to English."

"Please provide the text you would like me to translate from German to English."

Well, I actually didn't want to mention this, but I don't use VAGCOM.

@Bertil
I'm a bit surprised that you're so certain about my fuel temperature sensor. I'm also experiencing this jerking issue due to the ESP, and that's why I've already replaced the MSW (Multi-System Wiring) twice. Every time I have one particular MSW installed, the error code appears; with the other one, it doesn't. That's why I'm quite sure the sensor itself is faulty.

You're probably right about the other sensors. I'll definitely check that out.

Regarding the communication problem: with good adapter hardware, such as the Profi systems, everything functions as desired.

However, the numerous errors suggest a missing ground connection in the control unit or problems within the wiring harness.

Best regards, Rainer.

Regarding the communication problem: with good adapter hardware, such as the professional systems, everything functions as desired.

However, the numerous errors suggest a missing ground connection in the control unit or problems within the wiring harness.

Greetings, Rainer.

I completely agree with that. As I mentioned, I'm going to try to figure out the apparent mass issue. Thanks for your help...