No RPM Signal

From M-Tech Automotive

If you have communications with the ECU and under cranking conditions you are not getting an RPM signal, there are a few steps that can be taken to resolve this issue.

First ensure you are using shielded cable for the signal from the ECU to the VR (Crank Position) sensor, and that it runs clear of any ignition components such as coil packs and HT leads, as this can induce noise into the system.

The first is to check that the ECU is indeed setup for the trigger pattern that you are using.

Note that all M-Tech ECUs are pre-basemapped for the engine you told us the ECU would be fitted to, so this is usually OK.

If you are using, for example a 36-1 trigger system such as those used on a Ford engine, or a 60-2 setup such as those used on many GM vehicles, then confirm that it is setup as such by reviewing the trigger wheel settings under the basic setting menu. For more information regarding this, please see the Trigger Wheel Settings page.

If the ECU is setup as it should (all M-Tech ECUs arrive pre-basemapped for the engine which you specified at time of order) the next step would be to reverse the crank position wiring. In essence changing the two wires that connect to the VR (crank position) sensor around, and try again.

If you are still not receiving an RPM signal it is likely that you will need to adjust the sensitivity of the crank pickup circuit within the ECU. (V3 models only) This is a simply enough task. Remove the cover of the ECU and within you will notice two small blue boxes with brass screws on top. These are the sensitivity potentiometers. Turn them both fully anti-clockwise until they begin to quietly click. This has now set the ECU to be at its most maximum sensitivity. The RPM signal should now read fine.

If you are still having problems it may be that your VR sensor is not working correctly, or indeed it is not close enough to your trigger wheel. Please contact us for advice on the next step to take.