legacycentral bbs

i got a code 31.(91ss with jdm ver2 ej20g and ecu)
it comes on right after ignition on.
clear the code but still comes back.
perform input and output test.
i got 4.6v on closed and 0.5v on WOT
any idea?

Are you measuring the voltage at the ECU pins or at the TPS?

How does the car drive? Does it stumble when you first press the throttle?

i measured it from ecu pins.
car drive normal but it stumble when i first press the throttle.

Hmm, that's odd. All I can think of is that either the harness connector isn't making good contact with the ECU pin, or there's a problem inside the ECU.

It might be possible to pull the contact out of the harness connector and kind of bend the metal slightly to make it grip the ECU pin more firmly.

Did the problem just come up out of nowhere one day?

problem started after i did ej20g swap

Oh, so it's been there the whole time... How did you wire in the EJ20G ECU? Just used the stock wiring and modified it for the extra ignition channels? If that's what you did, and there was no code before, I guess that means the ECU is more likely. You don't have access to another ECU to test, do you?

found the problem.
worn out or loose pins cause code31.
replaced all three pins and problem fixed.
thanks

Nice work.