So the million dollar question is.......if I remove the hardware device, is there a tested method of using the software method to alter just the speedometer? I read that things still needed to be tested on that method. While I don't have access to a Windows device, I'm sure I could scare one up if I had to. But I hadn't heard of anyone actually making the changes for just the speedo.
- - - Updated - - -
- - - Updated - - -
While I hate doing projects twice, removing the device is pretty simple, but coming up with a plan to fix it via software will likely take far longer than the install and de-install. Once I hear of a plan to adjust the intentional BMW speedo inaccuracy, I will give it a shot.
It will likely take some experimenting to figure out how to calibrate it properly. Ive been in this community 10+ years now and never seen someone care so much about the speedo calibration as you. Thats not a knock against anyone - just pointing out that since nobody has cared about it in the past, it hasnt been looked into a whole lot...
The first page has a good post from 328i M Power (Abel). He would be the one Id talk to about this stuff, he is very good with these types of things. I ask him for help whenever diesel engines stump me and my inpa install...
I would start by getting the INPA pack installed on a spare laptop and then go from there. The calibration can be done, I am quite sure of it, but youll need the INPA tools to do it. Most notably NCS Expert. Start by installing that so by the time the knowledgable people post some ideas, you are already in a position to try it
Last edited by BimmerBreaker; 05-28-2020 at 03:06 PM.
Going into my TENTH YEAR of providing high quality reproduction BMW fabrics!
PRICE CUT on ALL FABRICS
Offering the best prices on the best quality reproduction fabrics!
I have begun the process of drinking the Grape Kool-Ade by ordering the USB-ODB cable and the ODB to BMW 20 pin cable. I have also downloaded the INPA software zip file. Now to find a Windows machine.......so far the Grape flavor is great...........
My fascination with a corrected speedo is just part of my automotive OCD.......
Last edited by bkirk; 05-28-2020 at 03:12 PM.
If you set your calibration way off, you can do 0-60 in 1 second. Thats hypercar territory. Just sayin...
Going into my TENTH YEAR of providing high quality reproduction BMW fabrics!
PRICE CUT on ALL FABRICS
Offering the best prices on the best quality reproduction fabrics!
Just a bit confused on the Windows / INPA software setup. I will get my hands on a friends old Windows laptop this weekend. He is done with it, so I am going to wipe his old software and get a clean copy of Windows running. I have ordered the USB/OBD cable that is linked, along with the 20 pin to OBD connection cable. Once I have the laptop and have transferred the software over, I've read about needing to perform surgery on the cable, since I will only be using this on a 1999 Z3 2.8L.
There appears to be a number of exe files on the downloaded files, so I will have to sort through those to see what needs to be installed. While I was reluctant to mess with the software settings on the vehicle, if I'm going to do it I might as well figure out what all I can see and/or do. Any pointers on what to install or what to avoid will be appreciated.
Yes, there is a function in my KMB daten file for selecting the "abs_sensor" as the road speed signal source. The option that's currently active however is "reed_kontakt", so still the diff sensor. A quick look at the wiring diagrams indicates the ABS module is connected to the DME, which is on the CAN bus. So, maybe it's talking already. Interestingly, CAN Bus is "aktive" for Tach, Coolant Temp, Gear Symbol and Fuel Consumption (also some non descript functions called CAN-BUS INSTRUMENT x).
Clever engineers, designing in a bit of fail safe by using different sensors. Just an FYI, the training module I have shows that for E38, 39 and E53, the left rear wheel ABS sensor feeds the cluster and is used for distance and speed.
Where did you download the files from? Most of the INPA program collections are packaged with everything you need and come with instructions that should be followed exactly. I'd stick with that for now. There might be some extra stuff but there are inter dependencies that are critical and not always obvious. To me at least.
Whether you need to modify the cable depends. Typically, what you need to do is bridge pin 7-8 in the ODB cable. really simple. It may not be necessary because it's already done. There's also a chance the 20 pin adapter might have the corresponding pins bridged inside it.
Last edited by ptony101; 05-28-2020 at 11:30 PM.
I downloaded from the link provided in an earlier part of this thread that listed the specific cables, etc. Since I have the 99 2.8 L which is the E36, its unclear to me after I get the software running where to find the data elements that deal with the speedo. But I have a few steps to go before I get to that.
Actually I would more say stupid engineers because they guaranteed that any wheel sensor problem will result in something in the car failing. Cooking a master signal by combining, comparing, and rejected outliers is the industry standard and doesn't end up with random subsystems dropping out.
And you're magical training manuals have been on the internet for many years. Read them all. Quote them often.
/.randy
The INPA install pack from the Z3 diagnostic thread should have instructions and the install .exes are in part 1, 2 and 3. Do them in order and itll be fine.
Going into my TENTH YEAR of providing high quality reproduction BMW fabrics!
PRICE CUT on ALL FABRICS
Offering the best prices on the best quality reproduction fabrics!
The pack I have there will work perfectly with your Z3 2.8 Coupe, and all the data you need is already bundled. You need the obd cable (INPA K+DCAN is good) no bridging required, plus 20-pin adapter.
I have been very busy with work, but will try to assist a bit when I can.
-Abel
- E36 328is ~210-220whp: Lots of Mods.
- 2000 Z3: Many Mods.
- 2003 VW Jetta TDI Manual 47-50mpg
- 1999 S52 Estoril M Coupe
- 2014 328d Wagon, self-tuned, 270hp/430ft-lbs
- 2019 M2 Competition, self-tuned, 504whp
- 2016 Mini Cooper S
Cables are ordered from eBay per the provided link. My friend gave me his old Windows laptop but it turned out to be an old Windows XP version that didn’t work with the software.
I bit the bullet and installed BootCamp on my new MacAir along with the latest version of Windows 10. Once the cables arrive I will finish the install and get back with any questions.
I suspect my questions will revolve around which data element will need adjusted to correct the speedo without affecting the odo.
Thanks.
I guess I didn’t realize that I was going to be a guinea pig, but so be it. After I completed the hardware mod to the speedo, the reaction was such that I thought there was another proven approach.
I’ll get the INPA software running once the cables arrive but it certainly sounds like I will need the collective knowledge of the group to determine what data element to monitor and/or modify.
Loaded my MacAir laptop with BootCamp and an up-to-date version of Windows 10. Ran all the installation programs and configurations in Win XP compatibility mode and all seems to be running as expected. One of my two purchased cables showed up today, the USB-16 pin OBD2 cable. That allowed me to finalize Com port settings.
I need to read more of the included files to figure out how to use the software for for the INPA and NCS Expert software do I need a vehicle specifc configuration file? I plugged in to the passenger compartment OBD port and nothing crashed, but I saw nothing change with the INPA software (readings, etc) and the NCS Expert software seemed to want a Profile file.
UPDATED: Reading PDF for NCS Expert now, will attempt to get connected later.
Last edited by bkirk; 06-02-2020 at 07:15 PM.
If not already in your software download (it should be) get NCS Dummy. It's like a decoder ring for NCS Expert and daten files. There's a NCS Expert profile you can download too. Search for "ncs dummy - taking the expert out of ncs expert". Its on this forum. The user guide is extremely helpful in understanding what's going on.
I'm right there with you but needed to do a lot more research on some of the data fields before I was willing to start coding. I also wanted to make a chart of actual vs. speedo readings, which i was finally able to do this weekend. So now I have my baseline and may try to re-code in the next few days.
To reiterate what I posted before, I'm pretty sure that the function that most likely affects the offset (called TACHO_OFFSET) is protected by NCS. You can't even read the actual value stored in that memory location with NCS, much less change it. At least that's what others have found when trying to fix the speedo on later series.
The one chance i think we have using NCS is a function called TACHO_SKALA_ENDWERT (SPEEDOMETER MAXIMUM VALUE). The choices are Europe, US and Japan. That's possibly significant because Japanese speedo's are reportedly 100% accurate from the factory. Sooooo, maybe just changing this will change the scaling factor for what's displayed on our speedo's. I'm game to try.
We will be a team of two trying to figure this out! But first I need to get my 20 pin to OBD connector cable on Thursday (eBay delivery date). Right now with my laptop connected to the OBD2 port I'm not sure anything is working yet. When I run INPA I'm not sure I'm seeing anything meaningful and frankly I'm unsure what I should be doing with it.
When I run NCS Expert, I get so far as choosing the EWS module and then get an error "VIN Faulty" and can't seem to get past that. I tried multiple profiles and even manually entered my VIN, but still got the same error.
What is the difference between running the software via the OBD port versus the under the hood 20 pin port?
- - - Updated - - -
By the way, this past weekend after determining that the odometer is also reset by the hardware fix for the speedometer, I then attached my Bluetooth scanner to the OBD port and went to the "Dashboard" functions to see what it was reporting as speed. While it displays the speed in a digital format with a decimal place, it was dead nuts on to the GPS (iPhone) and the speedometer indicated speed, which still has the hardware chip attached and its is subtracting 5.7% off the diff sensor......
So I'm not sure where the OBD port reading of speed is coming from, but until I remove the hardware fix I'm uncertain if it is affecting what the OBD port is reporting.
I've never tried to run INPA through the OBD port but a couple of things to consider. First, the cap for the 20 pin under the hood has to be on for the OBD port to work. Then, the only module you can read through the OBD is the DME. EWS is not available through it.
I believe the reason you were getting true speed from the Bluetooth OBD reading is that the DME gets speed info from the DSC module, which uses a wheel speed sensor (right rear), not the diff sensor.
Check what files are present in the "Daten" and "Sgdat" folders of your NCSEXPER folder
Does INPA work? Try talking to the engine through the OBD port in the car in INPA (for other modules youll need the 20 pin round port adapter)
I think our resident diagnostics software expert is pretty busy these days but im sure he will chime in when he gets a chance.
Going into my TENTH YEAR of providing high quality reproduction BMW fabrics!
PRICE CUT on ALL FABRICS
Offering the best prices on the best quality reproduction fabrics!
The Daten directory has 112 files in starting with BR_REF.DAT through Variable.DAT, the SGDAT directory has 1991 files in it starting with 00EK9284.IPO through Variable.DAT and there is an E36 directory for my 1999 Z3 2.8 L Coupe too.
I will wait until the 20 pin cable/connector shows up, but it was unclear to me if I was actually connected to the car in anyway, software wise. The cable was connected but the INPA software gave no clue as to be connected and the NCS Expert only gave the indication of connection by shoot an error on the VIN.
Dumb question, but when connected with INPA or NCS Expert, what should be displayed indicating a connection?
Bookmarks