heres the story just picked up a very nice clean low rust 2005 rx8 for dirt cheap kid i bought it off says the motor is blown wont run right. so go look at it car is clean but wont idle very well. so i bought it with the thought of just putting a scrap yard motor in it. now that i got it home and have checked it over looks like someone put a 4 port motor in a mt car. so is there any why to get this to run right or just easier to get junk yard motor and swap?

 

What a question!

Things to check: is it running a four port ECU? Four port fuel injectors? Check the ignition components, they wan wear out fast. Clean the air filter, inspect and clean the MAF. If all of that is ok, a rotary compression test will be needed. If the compression test fails, the only thing that will make it run properly is a tear down and rebuild.

The 4 port can certainly run and run all for daily driving, but the gears for the six speed US market transmission are not a good match for the 4 port engine. (If it's a five speed transmission, it's possible you have a JDM or Eurpoean drivetrain. They have been imported before).

 

4 port ecu wont run cause it looks for the auto trans. not sure on injector how do you tell? cleaned air filter cleaned maf and ecc kid said it had compression test 90-95 psi

 

There were 4 port motors with 5 speed MT available in most markets BUT USDM....so it could be an Euro, JDM , AUSDM market car

 

it keeps throwing apv valve codes cause there isnt one.

 

Does it have distinguishing features that may conclude if it not an american market car? Things like a lip spoiler, rear fog light, popout headlight washer nozzles, french or german writing on the door jamb?

You can call Mazda north America with the VIN to get the history of the car. At least the correct engine configuration

 

LOL...that might be a dead giveaway

I take it the car wasn't running when you bought it?

 

Sounds like a 6 port ECU on a 4 port motor. That would be a mess, the port timings are different, the injector staging is different (6 vs 4). Your best bet right now is to get an ECU and ABS box from a 4 port junkyard car.

 

its a canadian car english on door jambs and stickers. ill msg mazda with vin.
the car runs just keeps getting apv codes. got a few things to do before i can get it on road then see how it drives.

 

waiting for parts to get on road but did some reading on the site. its a 5 speed manual was that ever offered in canada?

 

Nope. Somebody probably swapped a JDM engine/trans in there.

 

4 port engine and speed trans were the low power option in Japan. Those motor / trans combos can be bought cheap. Someone probably blew your old motor, replaced it with the JDM stuff and left the previous ECU (4 port ECU would not throw an APV error....it never had an APV).

Your best bet? Find a wrecked 4 port (2004 or 2005 automatic) and buy its ECU and ABS box. Ask a Mazda dealer to reprogram your keys to that ECU. Replace ABS box yourself.

 

4 port engine and speed trans were the low power option in Japan. Those motor / trans combos can be bought cheap. Someone probably blew your old motor, replaced it with the JDM stuff and left the previous ECU (4 port ECU would not throw an APV error....it never had an APV).

Your best bet? Find a wrecked 4 port (2004 or 2005 automatic) and buy its ECU and ABS box. Ask a Mazda dealer to reprogram your keys to that ECU. Replace ABS box yourself.

Edit: the 4 port motor has a different red line and power band than the six port. You cannot trust your tachometer, you will have to shift early. 4 port should give you the warning beep at 7500, 6 port won't beep until 9000.

 

it came with the 4port ecu but the guy said it wont work. what is abs box?

 

Correct. The ECU and ABS box are "married" by Mazda at the factory. It is theoretically possible to marry a new one, but even Mazda dealers will balk at this request. Therefor the best option is to get another ECU, and it's married ABS box.

Edit: please see this thread. This is where I got my information, and the thread I am referencing for my ongoing 4 port to 6 port swap

https://www.rx8club.com/series-i-spe...t-swap-151684/

 

ohh ok can i get the new ecu to work with old abs ?

 

Your best option is to salvage an ECU and ABS box from a junkyard four port. The ABS unit has two pieces: hydraulic and electrical. It unscrews, and you just take the electrical. B

 

I think it'll be easier to give this car a 6 port engine and be done with it. Trying to mate a 4 port ECU and match ABS module into an original 6 port car is going to be a mess, and leave you with a 4 port.

 

In the end that is certainly the best outcome. I was trying to give the OP the best path towards a properly running and driving car, without pulling the motor.

 

it runs and drives with the 4 port with 6 port ecu. think i just use it for summer then get 6 port over winter

 

It won't run well. The intake and exhaust ports are different. The injector staging is different. The red line and shift points are different.

You also began this post saying it "won't run right" and "doesn't idle very well".

 

i changed plugs wires and coils cleaned maf and ecc runs much better now