Hi everyone I have a 1994 Miata with a 2003 vvt swap, has the entire harness from the 2003 so the car is pretty much an nb in a na's body. It ran fine and wonderful until I was dumb enough to lose the key, and as we know the 01+ has an electronic chip in the key that communicates with the ignition and sends a signal to the immobilizer which then allows the ecu to send spark. So I bought a 2003 ecu/immo/ign from a forum member he said it worked fine when he pulled it i believe him. Well when I put the new setup in the ecu wouldnt do anything and appeared to be dead, it only cranks but no fuel pump (i have a carter 255lph so you can hear it when it runs) and no spark. I grabbed the old ecu plugged it in and the the fuel pump came to life, but because of the immobilizer the old ecu will not send spark.
Why would the new ecu show nothing no dash lights no fuel. EGI relay( shows continuity and clicks on with old ecu)
So I thought it could be the new ecu so I had a friend bring over a known working ecu/immo/ign setup and his ecu did the same as my new one..
I have read that the 03 can be finnicky if the battery is less than 12.9v., but no ecu signal at all.
Keep in mind I have had an obd2 reader on all three ecus and the only one to read is the old or original ecu, the new 2 appear to be dead/no power.