Hello guys need little help here bought 04 rx and after having problems turning on after warm up I rebuild the engine but still shuts down after is warm and the idle goes up and down maybe one of you had the same experience please little help

 

Who rebuilt it ? What parts have been reused? Get a proper compression test and come back with the results.

 

Definitely need compression test results before advising further. Any CEL codes?

 

https://www.rx8club.com/new-member-f...ory%5D-271534/
Here was my thread where I went down just about any possible rabbit hole I could think of when every time it was just the engine build.

In short, just get a compression tester you'll spend more money on diagnosing everything else in the car.

A good solid rebuild should start instantly cold and within 1s hot. Even within the first 50 miles of break in.
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If you rebuilt it, what did you do for a side seal corner seal gap? 0.002in-0.004in? Listing the mileage of parts used and if they are oem or aftermarket could be helpful.
Housings?
Irons?
Corner seals?
Rotors?
Side seals?
Apex seals?
Springs?

 

Don’t get me wrong the car start and runs after the rebuild everything is ok is just after warm up shuts of but start right away no needs for compression test motor is new

 

Do you have any codes. I had that problem when I got mine rebuilt. Turned out to be the front o2 sensor. It was sending an ol-fault to the short term fuel trim. Not letting closed loop take over. Since the batt was disconnected for a while the ecu had no fuel trim in memory to fall back on and the o2 wasn't working to give new fuel trims.

 

it does sound like it might have something to do wit the catalytic converter because that is the only thing the warm up is for so check those O2 sensors like above suggests.