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Specialists
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ExtraEFI.co.uk |
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MS1-Extra and MS2-Extra
A Variable Reluctor (VR) sensor has no power supply fed to it, it has a soft iron connected to a magnet with a steel cable wound tightly around it thousands of times. When a metal surface passes in close proximity to the magnet the shifting flux induces a small current to pass through the coil. This is fed to the MS ECU via a screened cable, to help keep noise from being picked up by the cable.
The current from the coil is very small and this can be the cause of some RPM reading problems. The MS V3.0 ECU has 2 potentiometers that can be adjusted to ensure a good triggering from this small current.
So if you have a VR sensor and your setup's RPM fluctuates madly on the MegaTune screen, (e.g. 800 - 1600 - 2000- 800 - 1600 - etc) try the following adjustment.
Don't get this confused with Resets! If your MegaTune screen keeps freezing or resetting, this is not the same problem!!
See curing resets HERE.
Note:
If you have a 5cy, 6cy, 8cy, 10cy or 12cy wasted spark ECU be careful how you remove the lid as the Coil Drivers are bolted to the lid!
Ensure that no wires are trapped in the lid when re-fitting it!1) Carefully remove the lid by un-screwing the top 4 screws on the ECU (2 on each side plate).
2) These potentiometers (pots) both need to be turned fully anti-clockwise. This has already been done for you if you bought from myself, but double check it anyhow. When the pot is fully one way it will continue to turn but it will click. So turn it anti-clockwise untill you can hear it clicking.
3) Leave the top pot (R52) fully anti-clockwise. Turn the bottom pot (R56) clockwise 1 complete turn at a time and test to see if the rpm settles. Continue turning clockwise one turn at a time untill the RPM settles. It is perfectly OK to do this whilst the engine runs, just be very careful not to short anything out with the screwdriver!!
4) Turn the ignition off and refit the lid, being careful not to trap any wires.
