VR sensor issues

[Jez]

Hi

I've got a problem with a current setup an engine is running.

I have a 60-2 trigger wheel + Marelli sensor. The issue is that the waveform after the -2 gap does not drop down lower than +5v so I get long tooth gap errors.

Below is a trace at low-ish rpm where the issue isn't as bad but is present - you can see before the -2 gap the trace drops just below -4v. Imediately after the gap this only drops to +0.7v, then -2.1v then slowly makes its way back to -4v.

IMG_8098.jpg (160.5 KiB) Viewed 699 times

So the question is how to I resolve this? What causes it? I've tried a different sensor with the same results.

Any insight into this would be great.

[stevieturbo]

Can you get a proper oscilloscope trace of it ? Seems very weird. What input are you using ? Has it ever worked correctly ?

Can you get a visual on the wheel at all ?

If the wheel is sound and true, what about a hall sensor ?

But a proper scope of it, showing all voltages might yield a little more info.

[Jez]

Wheel looks straight

I'll get a scope on it and see whats happening - I've no reason to suspect Syvecs is misreading - guess it could be a weird loom issue.

[stevieturbo]

Wheel looks straight

I'll get a scope on it and see whats happening - I've no reason to suspect Syvecs is misreading - guess it could be a weird loom issue.

Not so much that it is misreading persay...but just in case there is an oddity with the sensor plugged into the loom vs not plugged in.

Testing not plugged with a scope in would at least prove the wheel and sensor are sound.

Also I'm sure some instructions say some inputs are better suited to crank/cam than others. I know on the S8's I've done I've kept them on AN13 and AN15 for this reason.