HLT switches my diesel to OTTO

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Mateusz
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HLT switches my diesel to OTTO

Post by Mateusz »

When investigating surprisingly high PS readings of my Galaxy 2.0 tdci, I realised the car settings automatically switch from turbo diesel to OTTO. It must be coming from OBD2 handshake. Can it be ignored? What difference does the engine type make?
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Harry
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Re: HLT switches my diesel to OTTO

Post by Harry »

The engine type influences power and consumption calculation. Otto engines are easy to calculate from MAF (and MAP) while Diesel engines require some assumptions on the diesel / air mixture. LapTimer retrieves the engine type from mode 1 pid 1 (DCT, see https://en.wikipedia.org/wiki/OBD-II_PIDs). In case the car delivers some wrong information here, it is possible LapTimer switches to the wrong engine type. I need to add I haven't seen this so far...

You can work around this by disabling 0101 in LapTimer's Expert Settings / OBD Tweaks (exclude PIDs).

- Harry
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Harry
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Re: HLT switches my diesel to OTTO

Post by Harry »

The engine type influences power and consumption calculation. Otto engines are easy to calculate from MAF (and MAP) while Diesel engines require some assumptions on the diesel / air mixture. LapTimer retrieves the engine type from mode 1 pid 1 (DCT, see https://en.wikipedia.org/wiki/OBD-II_PIDs). In case the car delivers some wrong information here, it is possible LapTimer switches to the wrong engine type. I need to add I haven't seen this so far...

You can work around this by disabling 0101 in LapTimer's Expert Settings / OBD Tweaks (exclude PIDs).

- Harry
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Mateusz
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Re: HLT switches my diesel to OTTO

Post by Mateusz »

I am glad to report that the workaround works well.
Horsepower calculation still points to a surprisingly high figures, but it is more sane for sure now. Diesel stays as diesel now.
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