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MX3KEV21 · Post by **MX3KEV21** » April 12th, 2007, 1:35 pm

can someone tell me if a 1994 mx3 ecu (k838) will be ok on my 1992 mx3 gs it fit the harness no problem. my old ecu had (k820) on it.

Custom_V6_Limited_SE · April 13th, 2007, 12:03 pm

You would be putting an OBDII ECU into a OBDI car. I think the OBDII cars might have an extra O2 sensor after the cat but I'm not sure. You could hook it up and pull codes with a 12v bulb going from ten to gnd in the diag box to see what, if anything, it will be unhappy about. The only thing I could see happening if it doesn't work right is poor gas millage. Do you already have this ECU or are you looking to buy it? If you are buying one, I would recommend just finding the older OBDI ECU to be sure that it will work.

JM1EC-V6 · Post by **JM1EC-V6** » April 13th, 2007, 6:39 pm

Custom_V6_Limited_SE wrote:You would be putting an OBDII ECU into a OBDI car. I think the OBDII cars might have an extra O2 sensor after the cat but I'm not sure. You could hook it up and pull codes with a 12v bulb going from ten to gnd in the diag box to see what, if anything, it will be unhappy about. The only thing I could see happening if it doesn't work right is poor gas millage. Do you already have this ECU or are you looking to buy it? If you are buying one, I would recommend just finding the older OBDI ECU to be sure that it will work.

1994 is actually OBD1 (OBD2 starts in 1996).

No problems running a 1992 K8, but your radiator fans don't have the correct connection with this ECU to get ON.