2004 Mazda3 no spark after motor swap...Help

Hey all, I’m new here but I came for help.

I’m stumped I swapped a running motor out of my 07 Mazda 3 it was a 2.3 into my 04 Mazda 3 hatchback . I know everything was fine I drove the car daily before pulling the motor and even pulled it in the garage prior to pulling the motor. I used everything from the old car. Wiring harness and even ignition and key. I’m not getting spark. I know the fuel pump is priming I can hear it and the fuel rail is filled with gas. I changed the cam sensor and also changed the crank sensor. I’m getting codes p0037 and p0043. I’m stuck i need to get it finished I have work in 2 days, car is ready to go besides no spark. I bled the clutch and got all of my mounts done. Also there is a harness that broke but I rewired it back in . Not sure if maybe I did it wrong?

I’ll post a pic of it for you to see and tell me . All grounds are tight and on there no anti theft light also the old car was an auto this one is manual but that wouldn’t cause it not to have spark right? I bypassed the Neutral safety switch.

Any help would be greatly appreciated ):
2005 Mazda3
Sure, I'll try to help... or at least give some leads as best as I can.

First and foremost, you're throwing p0037 and p0043 codes, which are from the heater block unit (that thing to the right of your engine block... have you tried swapping that over too? I'll give you a link to it later on this post). So that's for that.

Secondly, when the sparks are not going, and with any swap, things can always be tricky to troubleshoot(try testing the wiring circuits for each wire you swapped-are they showing complete? try swapping the original ECU?, could be a number of things..), but I'll be straight up with you man, this might not be the best forum to ask(there are some mechnically savy people here), however, on another forum, there are quite a few guys who have done motor swaps and shared their experience, you may want to try over there and perhaps they could help you out better(or have some better ideas) since they've done it.

Check this forum and thread out(it's for a 2.5 liter to 2.3 liter swap, but they run into some similar issues):

Hope it helps man and best of luck, I'm sure you'll get it working, sounds like you're pretty close.


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