soondin Posted April 13, 2021 Report Share Posted April 13, 2021 All tune is okay but have problems with vehicle speed input. Instrument's speed meter work okay. But E36X have no input DI1 until over around 90kph. Attached log at dyno during final tune. DI1 and GP Speed1 setup is same as base map. What I have to check? BMW E36_325_3036_T13.llgx Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 13, 2021 Report Share Posted April 13, 2021 >Digital inputs>GP Speed 1, is the pull-up resistor turned on? Quote Link to comment Share on other sites More sharing options...
soondin Posted April 13, 2021 Author Report Share Posted April 13, 2021 I've see this kind of post. But base map was already set ON. Try with OFF have same issue. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 13, 2021 Report Share Posted April 13, 2021 If that is the case I think you are going to have to find someone with an osciloscope to see what is wrong with the signal. Even above 90kmh it doesnot look like a usable signal. Quote Link to comment Share on other sites More sharing options...
soondin Posted April 14, 2021 Author Report Share Posted April 14, 2021 I will check with scope soon and let you know. Quote Link to comment Share on other sites More sharing options...
soondin Posted April 14, 2021 Author Report Share Posted April 14, 2021 19 hours ago, Adamw said: If that is the case I think you are going to have to find someone with an osciloscope to see what is wrong with the signal. Even above 90kmh it doesnot look like a usable signal. Please see attached image. At ECU coonector PIN 42 (DI1) Have input as attached picture. Speed.llgx is logs during scope test. Speed.llgx Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 14, 2021 Report Share Posted April 14, 2021 I think the most likely problem is the signal is not falling below 1.0V, it looks like it drops to about 1.1V. That would suggest the circuit that generates this signal possibly has a bad ground. Two things you could try; The easiest one would probably be to add a diode inline with the speed signal on pin 41 at the ecu. A diode will drop the voltage by about 0.7V. You could try to trace the ground for the cluster as shown in the diagram below and connect it to ecu ground instead of whatever it is connected to now. Quote Link to comment Share on other sites More sharing options...
soondin Posted April 14, 2021 Author Report Share Posted April 14, 2021 Inline diode is not work. Can't change DI low voltage to around 2.5V? Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 14, 2021 Report Share Posted April 14, 2021 5 minutes ago, soondon said: Inline diode is not work. Why not? What voltage did you see with the diode connected? 5 minutes ago, soondon said: Can't change DI low voltage to around 2.5V? No it is hardware, not software adjustable. Quote Link to comment Share on other sites More sharing options...
soondin Posted April 14, 2021 Author Report Share Posted April 14, 2021 24 minutes ago, Adamw said: Why not? What voltage did you see with the diode connected? Used 1N5819 what I have drop voltage almost same. 26 minutes ago, Adamw said: No it is hardware, not software adjustable. I see, I will try check ground. but no one have this symptoms with E36X? Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 14, 2021 Report Share Posted April 14, 2021 30 minutes ago, soondon said: Used 1N5819 Ah yes, that is a Schottky which will have very low forward voltage drop at low current. Try a something like a 1N400X. 30 minutes ago, soondon said: but no one have this symptoms with E36X? Not that I have seen reported. The switching threshold of 1.5 & 1.0V on our DI's has been the same since G3 ecus about 15 years ago. So is fairly well proven and works well for most sensors. A ground offset of more than 1V is pretty unusual and suggests there is a bad connection somewhere. Quote Link to comment Share on other sites More sharing options...
soondin Posted April 14, 2021 Author Report Share Posted April 14, 2021 1 hour ago, Adamw said: Ah yes, that is a Schottky which will have very low forward voltage drop at low current. Try a something like a 1N400X. I do test again with 1N4148 drop around 0.75V one but same. Quote Link to comment Share on other sites More sharing options...
soondin Posted April 30, 2021 Author Report Share Posted April 30, 2021 Solved with inline diode and pullup off can see input speed. Calibration is okay. Quote Link to comment Share on other sites More sharing options...
briannmendiola Posted June 13 Report Share Posted June 13 Is the chassis obd 2 or 1? My car is obd2 but running an obd1 harness. In my case I should connect pin 9 on x20 connector to pin 42 DI 1 for speed? 1998 328i 1994 325i harness Quote Link to comment Share on other sites More sharing options...
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