I have a rx8 automatic 2004 model. And the ecu ‘s part number sticker is damaged, and i cant find the part number, where can i find it? I need a new ecu as my car cant remember the fuel trim, and whenever i hot start my car, car shuts off if i dont rev very slightly (like putting foot on throttle and pushing a hair line max)

 

That doesn't sound like an ECU problem, it sounds like a compression problem. Have you tested that?

 

Compression is 90-100 psi in all of them, and no hot start or cold start issue.

 

This still doesn't sound like an ECU problem. Not learning fuel trims is not a thing, any more than your phone forgetting phone numbers. If a sensor is misbehaving, or the fuel trims aren't enough to overcome unmetered air coming in, you might see what you're seeing. But the solution isn't to replace the ECU.

What diagnosis was done? Are there any codes? Does it still do this after a drive cycle or two?

90-100 is technically failing if that's at 250 rpm. Should still run though.

 

any Mazda dealer can pull it up based on the VIN

here’s the appropriate thread as well

https://www.rx8club.com/series-i-tec...stings-259366/

have no input on the actual issue at hand otherwise, but good luck …

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No codes found, car is facing this problem, only when i redline constantly, and shut off the car, and few mins later when i start it up again.

 

Must be a bit more to go on than that....

Why is that the operating parameters? Drift car?

 

Is there oil on your MAF sensor and in the intake?

 

operating temp is 201-209f water temp,in stop and go traffic. And 200-222f oil temp.
with a ambient of 30c ambient.

 

did not check.

 

Why so high in the rev range all the time?

Remember that you won't get fuel trims when you are in open loop areas like high rpm and load. Closed loop is for middle of the road load ranges when the computer is fast enough to compensate for changes in AFR.

 

no i drive under 2k rpm in high traffic areas,i only redline at night(when roads are free).
and when i turn off the car mayb for 5-10mins, i hv to face this problem,when i restart the car,car starts,but rpm fluctuates and car shuts off. Then i have to start the engine again.

 

I would doubt that it is an ecu fault. There are so many other places to look first

The ignition is notoriously an issue... and depending on the age of the car you can get O2 sensor issues MAF issues or other fueling issues that are much more likely

The compression being down doesn't help... sometimes when you have a low rotor the idle is the first thing that suffers... especially after a warm start when the extra fuel added for startup can wash out the compression even more.

I would check the plugs... and test the ignition with a HEI tester first. Remember that the trailing plugs fire first at idle... and make sure they are OK. They are cooler plugs and can foul much easier than the L plugs.

 

ignition and plugs r new, drove 1000km only. Decat and fujitsubo exhaust installed,with aem intake.
no codes, i believe if o2 sensor and maf was the problem,car would give cel

 

I would still check the ignition. I have seen new coils fail almost immediately. And plugs can do the same. At least pull the plugs and have a look. Often you can get an idea about what's going on by looking at them

You could also have an injector that is leaking a bit... it would be more apparent at idle

Best way to figure stuff out is to start at a baseline and check everything. You know the thing about assumptions...
Makes an " *** out of yo​​​​​U and ME" 😁