2005 Rx8
Manual GT

I bought my 8 back in July knowing it needed an engine. I put a JDM in it back in October. I've got everything worked out except it continues to stall. All the codes were related to the SSV.

When cold and starting, the car turns on fine and I wait for it to warm up before driving. When driving more than 15 minutes or so and the car will die when pushing the clutch in. The rpms don't even try to recover, it just drops and dies. I have to sit for a while before turning it back on and it takes a couple tries. Originally I thought it was plugs and coils so I replaced those, then a new fuel pump, then my ssv solenoid, but the problem still persists. If I keep the car below 4k rpms (which I know is bad) it will drive a lot longer but will still eventually die. I gutted the cat and their are no engine codes. I'm at a loss of what to do next.

Does anyone have any ideas on what might be causing it to stall out?

 

"JDM" engines are identical to "USDM" engines and "EUDM" engines. There is no physical difference in part numbers in any 6-port series 1 engine. Same worldwide.

Get a compression test. Stalling when hot and not restarting when hot are classic symptoms of engine compression failure. If the engine is literally new, less than a couple hundred miles on it, then the compression is still increasing rapidly as you break it in. If you are past ~5,000 miles, it's bad news. A new engine shouldn't have compression so low it does this, but a poorly built one can do it for a bit until it breaks in. Such an engine will never return good numbers, being marginal at best.


At a guess, someone marketed this engine as a "JDM" engine to get more money than they otherwise would for a badly built engine, since plenty of people go gaga over "JDM" without actually bothering to investigate it.