Vems Tacho issue

[murat]

Hi Everyone,
There seems to be a difference between the tacho rpm and vems rpm.

When Vems is idling aroun 1000 rpm, tacho shows 800 rpm.

What could be the issue?

[A80Avant]

What firmware are you using?

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[murat]

1.2.2

[A80Avant]

With this version vems is using the flywheel sensors as to judge the rpm. There is no calibration feature.
I was told that once vems works this way its unlikely to be wrong unless you had the flywheel modified and pins not properly welded. So in other words the speeding is wrong and vems is right.

If you tap the speeding screen gently does the needle go up at all?

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[murat]

I also believe vems is right.
It feels like 1000 rpm not 800.

The tacho seems to be working properly. I believe there is signal from vems to tacho, could it be an output config issue?

[A80Avant]

No. Its unlikely. The signals to tacho from vems are within the hardware of the ecu and as far as I know not able to be calibrated. If the tacho shows wrong it could be a mild issue with the tacho instead.

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[Kieron20V]

Have you change your clocks/spedo to V6 ones by any chance?

[murat]

I didnot

I own the car since 2004. I did not have this problem in previous years.

maybe not a vems problem.

how to diagnose??

[A80Avant]

Just don't worry about it. Tachos tend to become slightly irregular with time. Not worth loosing sleep over it.

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[murat]

I am checking the log an it seems, the error is around 1000 rpm in the redline.

my fuelcut is set at 7399
ignition softcut at 7500 rpm.

in the tacho I see 6000-6500(i dont remember exactly)

I am attaching the log

[A80Avant]

Do you use stock flywheel?

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[murat]

as long as I know it should be stock. I didnt changed it.

how to check if its stock or not??

[A80Avant]

Look between the engine and the gear box. If there is a metal gasket, thick one then you have stock flywheel

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[murat]

Checked vems config. Changed tacho divider to 14. It was 17 previously.

Idle rpm fixed. Will also try redline.

[A80Avant]

O haven't seen my conifg recently but cannot recall my version to have such a setting. Under which category is it?

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