BMW M328i, Easier than a Type-R Sticker

I can’t make this stuff up, I really can’t. I found out why the Vanos isn’t working, and it’s not what I was thinking…

I have been messing around for the past few days trying to get INPA and DIS to work properly. I can get INPA to read everything but the DME (ECU), but I finally got DIS working today, and its reading the engine DME.

This means I can finally read engine codes and see if there is anything obviously wrong.

That’s a yes then. This was the only code, thankfully. I had wondered about the TPS since the reading from live data in the VNC (Vanos Control unit) in INPA was weird, but the VNC didn’t have codes for those sensors, only Vanos related ones (of which it had an old code for something random in German, which wasn’t an active code).

So what was weird? Well, the Throttle Position Sensor either read as below, with the engine off

And didn’t change when the throttle was opened, or did this when the engine was running (also note the two bars at the very top not reading anything)

That reading looked familiar…. almost like it was reading engine position.

I disconnected the plugs, and checked the wiring colours. This was the plug off the TPS

And the Intake Cam Position Sensor

These two live right next to each other, and have identical plugs.

I check the wiring diagram, and sure enough the TPS colours were wrong. It should be Brown, Brown/Black and Red/Yellow

And the CPS should be Yellow, Black and Shielded Brown

So, what does that mean? Well, the two connectors had indeed been swapped. I swapped them over, connected them as they should be, and checked in INPA again.

The TPS now read correctly, and I also noted that the two top bars now also had a reading, so suspect that’s linked to the cam sensor.

You can also see from the above photo, that the engine finally idles at the correct RPM now too. Obviously the engine thinking it was at WOT, but not moving, was causing the DME to keep the idle up.

The result? Its picked up a lot of down low power, almost like the Vanos is now actually doing something. Funny that. Easy way to gain power, much easier than Type-R stickers or a pod filter.

The exhaust sounds different too, I suspect this is down to the cam timing being correct now, instead of the inlet cam just sitting in one spot (or maybe even varying depending on throttle position!)

With the idle also correct, unfortunately the misfire at idle is more obvious. Hopefully it’s either Vanos, or something simple like spark plugs or coils. I’ll check them out shortly.

I can only presume this switch happened when the previous owner had everything unplugged to replace the head gasket. That was in 2016, so obviously it’s been wrong for a while now, but confirms that I was right about the Vanos not working.

It’s still slower than my old M3, but hopefully rebuilding the Vanos can make that gap closer.