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E39 OBDI Cluster
Posted: Thu Oct 06, 2022 12:30 pm
by johnspark
I have just successfully got the economy meter which displays litres/100km to work linearly with a variable pulse width.
Used ZK-PP1K from E-bay to generate the PWM I fed into the TI Signal of the cluster. Must have RPM showing a value, and also the speedo must have some value on it. I have not quite worked those 2 bits out, but all they do is disable or enable the economy meter from working.
Please see the excel spreadsheet to show the PWM % variation at 500Hz vs Litres/100km displayed. It is quite linear. Tried at 200 Hz but the meter became very sensitive. So prefer 500Hz value. This meter will be able to display energy consumed / 100km, or power consumed / 100km. (I think energy is better). It appears that if RPM meter reaches 1500 RPM, the economy meter is enabled. If the RPM meter falls below 1200RPM, the economy meter is disabled. Meter has to go back to 1500RPM before the economy meter will be enabled again. Only thing, I don't know what the threshold is for the speedometer, so I am going to install 3 of these ZK-PP1Ks, so I can work that out too.
I would like to use this with the zombieverter ECU
Re: E39 OBDI Cluster
Posted: Thu Oct 06, 2022 12:33 pm
by johnspark
The spreadsheet seems to be lost so here it is again...
Re: E39 OBDI Cluster
Posted: Tue Nov 01, 2022 3:08 am
by johnspark
I have now added a third ZK-PP1K pulse generator (from Ebay), so there is one for the TI, TD and Rear Left Wheel Sensor inputs. I have updated the spreadsheet to accommodate these changes.
Re: E39 OBDI Cluster
Posted: Tue Nov 01, 2022 9:10 pm
by johu
Good find
Re: E39 OBDI Cluster
Posted: Fri Feb 10, 2023 9:48 am
by Zechy
Great info!
What voltage did you use for the signal?
Re: E39 OBDI Cluster
Posted: Wed Feb 22, 2023 12:11 pm
by Zechy
Woohoo! Managed to get the rpm to move using the pwm signal generators from ebay.
12v in. negative pwm signal on pin 6.
Not all e39s have CAN bus to the instrument cluster. Mine is a 1998. The "Vehicle CAN" setting won't work. Will have to come up with another plan
Re: E39 OBDI Cluster
Posted: Fri Feb 24, 2023 8:02 am
by johnspark
Well done Zechy!
Is yours OBD1 like mine? If it is, you can get the speedometer to work like that too. Copy mine. That's a black / white wire.
The economy meter is dependant upon TI, TD (RPM) and the speedometer pulse width values received. 'TI signal R2.xlsx' has all three, -I find it a bit hard to read, and I wrote it!
This is the formula for the economy meter: 25.4*[TD/(TI*{km/hr})]-1.
If any of the three signals fall below the threshold shown in the spreadsheet, the economy meter reads zero. Therefore if the car is stationary, the economy meter reads zero, instead of infinite L/100km, for example.
Practical tip from spreadsheet:
In actual EV conversion, use TI signal and TD signal inputs found in Engine and Transmission ECU box. Rear Left Wheel sensor input for speedo or left or right speed sensor data can be obtained from ABS module behind glove box for Australia. (Perhaps safer to use input to speedo on instrument cluster).
Also, speedo cannot be adjusted, and RPM cannot be adjusted, therefore do all calculations with TI to get economy meter to present what you want it to. (I want to use it as a power meter).
Re: E39 OBDI Cluster
Posted: Sun Mar 12, 2023 1:50 am
by Zechy
johnspark wrote: ↑Fri Feb 24, 2023 8:02 am
Well done Zechy!
Is yours OBD1 like mine? If it is, you can get the speedometer to work like that too. Copy mine. That's a black / white wire.
The economy meter is dependant upon TI, TD (RPM) and the speedometer pulse width values received. 'TI signal R2.xlsx' has all three, -I find it a bit hard to read, and I wrote it!
This is the formula for the economy meter: 25.4*[TD/(TI*{km/hr})]-1.
If any of the three signals fall below the threshold shown in the spreadsheet, the economy meter reads zero. Therefore if the car is stationary, the economy meter reads zero, instead of infinite L/100km, for example.
Practical tip from spreadsheet:
In actual EV conversion, use TI signal and TD signal inputs found in Engine and Transmission ECU box. Rear Left Wheel sensor input for speedo or left or right speed sensor data can be obtained from ABS module behind glove box for Australia. (Perhaps safer to use input to speedo on instrument cluster).
Also, speedo cannot be adjusted, and RPM cannot be adjusted, therefore do all calculations with TI to get economy meter to present what you want it to. (I want to use it as a power meter).
Yes. I have the same OBD1. It confused me for a long time until I found your post.
I'll definitely try to get the speedo working. Thank you!
Re: E39 OBDI Cluster
Posted: Sun Mar 12, 2023 9:51 pm
by johnspark
Well that's awesome Zechy
.
The 3rd spreadsheet I created is absolutely correct with the numbers. I had to wait for some of the numbers to settle down before I recorded them. I never got around to rearranging the data in the spreadsheet to make it a bit more readable.
Rearranging equation I get: TI = 25.4*[TD/(Economy+1)*speedo]. {Hopefully others will double check this}.
We know speedo, we know TD (RPM), therefore we can get TI for a particular Economy (L/100km) value that we want displayed.
I will use Economy to display power (kW), for my conversion.
Re: E39 OBDI Cluster
Posted: Sun Mar 12, 2023 9:54 pm
by johnspark
Oops! not 3rd spreadsheet, but R2 spreadsheet...