I wasn't sure how I wanted to tune the M20B29. Recall I put the stock E30 325i ECU in. Options included doing a standalone, tuning the 325i box myself, going with one of the open source projects, etc...
I discovered that Classic Daily had taken one of the open source ECU projects and built their "BMW E30 M20 PLUG AND PLAY ECU" around it.
https://www.classicdaily.net/collection ... d-play-ecu
I figured it was worth a shot so I ordered one. It came Friday and I dropped everything to install it...
The kit is advertised as PnP, and for the most part, it is...
The 3D-printed case fits exactly. Not a huge fan of 3D printed cases for things (questions about durability, they look cheap etc...), but it works.
Kit includes a vacuum hose and tee for tying into a vacuum for a built-in MAP sensor (vs MAF/AFM).
Jake's email to me fell into my junk folder so I missed him asking what intake I wanted; he sent one designed for a hot-air intake. He will send me the one that bolts to the OE M20 air filter housing with the AFM removed. That'll be slick. The tube includes a temp sensor with a pigtail that connects to the AFM connector.
The kit includes a new TPS with a 3D-printed adapter and connector extension. This connector extension is needed because the modern TPS fits upside down and the OE TPS wire is too short to reach. Nice touch.
The ECU will work with a narrow band O2 sensor, but Jake "highly recommends a wideband". The odd thing is the ECU doesn't *directly* support a wideband input, one has to use an external wideband controller. Jake says future versions will include the wideband controller circuitry. This means I needed to figure out how to get a wideband O2 sensor and controller in.
To get the car running, I used one of my Innovate LM2 wideband meters (and associated 4.9 O2 sensor) which has an analog out that can be plumbed into the AUX connector on the ECU. This is a hack: The LM2 is super sensitive to input voltage and doesn't provide an output signal unless it sees way more than 12V, it's plugged into the cig lighter socket which is never a great/solid fit (I've used some electrical tape to ensure it doesn't wiggle loose while driving), and was never designed to be a permanent install. I'm gonna get a different wideband controller (probably AEM) ASAP.
The kit includes 3 Molex connectors and pins for the 3 plugs on the ECU: Aux, CAN bus, and something else I'm forgetting. In 2023 a Molex connector is an odd choice. But it works. Jake was super helpful in getting me a brain-dead sketch of what pins to wire in from the Innovate LM2.
By yesterday evening I had the car running again. I had to get Tuner Studio. I have now three tuner software packages: TunerPro/KDMAx (Tacoma), Tuner Studio, and ecuworx (S54). Sheesh.
Intially it was running insanely lean. It turns out the tune Jake pre-programmed was set to much higher flow-rate injectors. Once I used Tuner Studio to change the Injectors I used (325i Bosch 0 280 150 715 injectors, which have a rating of 149cc/min), it was much better... but now too rich (better than lean!). I'm no tuner, but was able to get the map to look good at idle. I did a test drive with some WOT and got Jake the logs and he's gonna get me a better tune today. I'll upgrade my injectors to a higher flow rate as well.
The LM2 / O2 sensor are also doing something funky where the AFR reading is jumping way high irregularly. Not sure what's going on there.
So far, it looks like a good purchase. Jake needs to up his game on documentation. My feedback to him on this:
- Explain each part. E.g. why there's an extension for the TPS, that the temp sensor on the intake tube will plug into the AFM connector, etc...
- Make it clear all else that's needed, especially a wideband controller. It would have sucked if I didn't have a spare LM2 / O2 sensor lying around).
Hopefully, today I'll get a new tune that really lets me exercise it...
