Hi folks-I've been playing with INPA on my e36 m3 and came across a tab labeled "Rough". Its a bar chart of each cylinder with different values. Anyone have an idea of what these values mean and if they indicate any issues?
They are a calculation based on crankshaft position sensor and how fast the crank spins by, to estimate burn quality.
They should be close to the middle with a little fluctuation, all at idle.
If a cylinder is bad, it will be way off.
-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
Bear in mind that if one cylinder is bad, the readings for both the following cylinder and the opposite cylinder in the firing order will also be affected.
Thanks. Not sure what you mean by the cylinder is "bad"? Is it a misfire, or is it a fault in the crank sensor?
The crank sensor cannot fault on just one cylinder, it's reading from a toothed ring on your crank.
One cylinder being 'bad' would mean the combustion is poor (even up to a misfire), possibly due to ignition coil/spark plug... or worse: loss of compression in that cylinder.
The rough test is quite sensitive to poor ignition, showing a change before you even get a code for misfires.
-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
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