Mitsubishi EVO (USDM) wiring diagrams for HFS-3 (all US models)

[tephra]

so basically. if you disconnect the brown/white and black wires from the chassis/ecu, and then test them you should find that:

with the gauge OFF =
OMH meter between white and black should show 0ohms or thereabouts (ie some continuity)
OMH meter between white and brown should show not-connected or thereabouts (ie no continuity)

with the gauge ON =
OMH meter between white and black should show not-connected or thereabouts (ie no continuity)
OMH meter between white and brown should show 0 ohms or thereabouts (ie some continuity)

if we can at least establish that baseline then we can move forwards.

^ all assuming you have DFS unlinked, FS0 linked?? and power to the HFS3 ...

Also FYI a reading of '0.L' implies NO continuity, it's not the same thing as 0 ohms...

[Richard L]

Originally Posted by tephra

so basically. if you disconnect the brown/white and black wires from the chassis/ecu, and then test them you should find that:

with the gauge OFF =
OMH meter between white and black should show 0ohms or thereabouts (ie some continuity)
OMH meter between white and brown should show not-connected or thereabouts (ie no continuity)

with the gauge ON =
OMH meter between white and black should show not-connected or thereabouts (ie no continuity)
OMH meter between white and brown should show 0 ohms or thereabouts (ie some continuity)

if we can at least establish that baseline then we can move forwards.

^ all assuming you have DFS unlinked, FS0 linked?? and power to the HFS3 ...

Also FYI a reading of '0.L' implies NO continuity, it's not the same thing as 0 ohms...

Thanks for posting and help with the connections.

[tephra]

no problems!

so Chris - can you confirm that:

with the gauge OFF =
OMH meter between white and black shows around 1 ohm (ie some continuity)
OMH meter between white and brown shows 0.L (ie no continuity)

with the gauge ON =
OMH meter between white and black shows 0.L (ie no continuity)
OMH meter between white and brown shows around 1 ohm (ie some continuity)

if thats the case then:
1) reconnect the white output back to the ECU pin (ie where you had tapped into before - you had cut the existing wire obviously because your ECU was reporting that the fuel temp sensor had an error)
2) connect black wire to a 250ohm (ish) resistor, then then the resistor to ground.

quick explanation:
When the ECU sees the voltage go ABOVE the threshold (ie no continuity condition) it will start the timer to swap to alternate maps.
When the ECU sees the voltage go BELOW the threshold (ie some continuity) it will INSTANTLY swap to normal maps.

Lastly is DHB linked or not?