Hondata

Car is a '91 Civic wagon RT4wd, k20a2, prayoonto stg 2 cams, modded DC header, cai

Just got the car running for the first time, starts and runs but ECT is always stuck at 124 or 177, not sure why it changes. At ambient temperature it reads the same. Even with the engine running there is zero change. Checked ground and power and they are good, wiring checks out. Anything else I should be looking at?

Also, batt voltage reads between 14-15v with key on engine off, is this normal? Reads correctly with engine running.

This is not normal. You need to try the ECU on a known working vehicle and see if it reads correctly.

That's unlikely as I don't know anyone with a Honda even.

I checked voltage from the ecu again and key on not running I get 10.4v! Is the main relay the only source of power for the ecu? I used the recommended wiring diagram from hondata. I'm not sure how the ecu would output this high of voltage without having internal problems. The kpro4 is brand new, never been used on a different vehicle.

Any help appreciated

You may need to find a local dealer, or shop, or check facebook to find a local person who can assist with trying the ECU in a known working vehicle. There is no risk to the other vehicle as it will only tell you if you have a wiring issue in your vehicle or if the problem is a damaged ECU that the symptoms follow the ECU.

Any chance the ecu would work in an '08 element? All I need is for it to be online and read all sensors correct?

No, this will not work in an Element.