MEFI 4 sensor supply voltage
 

Hi all,

I'm trying to debug my MEFI engine control unit TPS. For some reason the voltage on all three wires seems to be same and close to zero so my question is that should there be supply voltage for the TPS when the power is on or does the MEFI require the engine (starter) to spin before it supplies the TPS voltage??

Thanks,

Oopee

nope,ecu supplies the 5volts to the tps.which mefi do you have,,mefi4,4a or 4b?

Hi sutphen and thanks for the quick reply!

Yes I know that it is the ECU that finally supplies the TPS but what I meant to ask is that does it give the 5 V to the sensor electronics all the time whenever the power is switched on, or only after the starter starts to spin the engine?

I need to check my ECU version I only know that it is number 4.

Thanks again,
Oopee

with the key on,,it has voltage,,look at the red 12v supply voltage,,either the relay is burn out or fuse.

Thanks, I will check!

Oopee

It does not matter what MEFI is used here - Are you using a scan tool as well or how are you testing the systems ?

Testing TPS reading with a scan tool -

At dead Idle fully warmed engine TPS reading should be .7 thru 1 volt and a WOT TPS reading should be around 4.8 Volts on the scan tool

That was point 7 ^^^^ to 1 volt at dead idle fully warmed engine