heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

Thats cool. Got a pn for the plug?

Yep! 61349316116

[0-60motorsports]

Thats cool. Got a pn for the plug?

[heinzboehmer]

Okay so INPA does not show EGT. However, I did learn that DIS can grab a ton of information from the DME under DME -> Expert Mode -> Diagnosis Requests.

Here's EGT (amongst other sensors):



And a sample of other interesting things like oil level and VANOS timing:




Now just need to sniff D Bus while I open up all the different screens to reverse engineer all this data. Honestly sounds like a lot of tedious work, but having all that data in a log does sound very appealing...


Also, I can't believe I forgot to show off my most important mod to date! Easy 20 hp from this thing:



In all seriousness, the open 12V socket was annoying me so I bought one of the modern BMW 12V socket plugs. Don't smoke, so no need for the cigarette lighter one and I like how this one is less busy.

[Bry5on]

Brilliant idea to record the traffic during an INPA session

[heinzboehmer]

Stuck home with a cold this weekend, so I knocked out some boring maintenance that I had been putting off for a couple months.



Swapped fuel filter, filter to fuel rail line, EGT, PCV line that goes to the airbox and a bunch of underside trim clips/screws that were starting to get old and worn. Always fun to do your best to evacuate the system of fuel beforehand, only to still have it spill everywhere.

Everything else was uneventful. I haven't seen the intermittent EGT code I was getting pop back up and EGT readings on Gauge.S are different now. I say "different" and not "correct" because it's clear the scaling is still way off.

Originally, I was planning on using this new sensor to calibrate the Gauge.S reading. DME has this table for the sensor:



And a third degree polynomial fits it perfectly:



So, it should just be a matter of exposing the sensor to a few known temps and measuring its output to correlate it with the graph.

I was about to head to the kitchen for some ice water when I realized that the DME is likely not sending out the raw sensor values over D bus. All other temp sensors are scaled linearly in the output data, so it would be very unlikely that this one is different. I'll check to see if INPA or DIS show EGT. If they do, it should be super easy to figure this out using a technique like this one: https://github.com/tomicooler/bmwe46...il-temperature

I did also set up the cheap logic analyzer I got and started trying to figure out why the V5 Gauge.S doesn't work with the DME, but the V4 does. Here's version 1 and 2 of my D bus probing setup:




I haven't really gotten anywhere yet. The V5 board on older firmware was sending out the correct DS2 commands, but would then hold D bus low and not allow the DME to respond. Updated the firmware and swapped the janky trimpot I had used as a D bus pullup for a properly sized 10K ohm resistor, then tested again.

Janky:



Not janky:



Now Gauge.S sends out the correct command and the DME responds with a valid response, but for some reason the device still does not display anything. It communicates just fine with the MK60, so I'm fairly convinced this is a FW issue. Unfortunately, Gauge.S FW is closed source, so I can't really debug this...

Anyway, I'll keep messing with this and update with any resolutions.