MoTeC Global Forum

G'day. I'm running an RB30 on an M48 in a nissan patrol. The engine uses the factory VL/R31 inlet manifold and injectors etc, extractors on the exhaust.

I am using a delco 1 bar map sensor (green insert) which is being used as the load reference for the ignition map.
Every time the throttle is released from over about 3000 rpm, the output from the map sensor approaches 0V (high vacuum) and triggers a fault code within the motec. The map sensor is conected by a short hose ~300mm, directly to the plenum of the inlet manifold. Is there a delay value that can be set on error detection so as to ignore this momentary excursion in map output as an error?

Thanks

This error is normally ignored on the m4 & m4-8.

You will find that it flags a error but still works correctly

The error is not ignored, the ECU uses the default values for the MAP sensor untill the diagnostic timeout self-resets it (currently set to 10 sec)

My point is, if the sensor is not faulty (have tried another just in case) then the ECu should not log an error for this condition. Is there something else to look at?

What version software are you using?
Have you set it up as a 1 bar Delco sensor?

Software is current version V6.20D
ECU itself is an older one, still requires the external SUU to do updates etc.

Yep, sensor is set to 1bar Delco in the program.

The error is caused by the high vacum created by your engine under closed throttle conditions draging the sensor output voltage outside of the range the ECU expects as sensable.

The workarounds are:
Set your sensor default value to 0KPA and error hold time to a short value (and ignore the error)
Fit a restrictor with a 1mm hole or less in the vacume line to the map sensor.
Replace your 1 bar sensor with a 1.05 bar or 2 bar map sensor.