Hi, guys!
I bought rx-8, 2004 release, 125 000 km run, engine 13b after rebuild.
I replaced all of consumables, ignition coils, spark plugs, ignition leads, fuel pump, 2nd O2 sensor.

No matter, cold or hot engine, but have this problem:
after start, working normally, then idle turn unstable


Please help!
Dont know what to do!

 

clean maf

 

thx, but i have 4 different maf's, one of them new

 

did you reset the ess with the 20 brake stomp? a lot of people forget this when swapping a new motor. who rebuilt it? do you have current comp #s?

 

yes, i reset the ess, dont know who rebuilt it.

it may be due to low сompression?

if i unplug the maf sensor, idle turns normal

 

you should always get comp check before buying. do you have anyway to data log? vac leak possibly?

 

thanks for help, i cant do data log, have no openport adapter

i do test for vac leaks, doing some smoke in inlet manifold after throttle valve.

 

Maybe

 

no,its not help, anyway i have this problem

 

You need to test for leaks between the MAF and throttle body.
How old is this rebuild and did the car have this behaviour since you bought it or its new?

 

If it runs better with the MAF sensor disconnected and you've tried several different MAF sensors, then it's time to check your wiring and connector.
This page should have the applicable wiring diagram for you to test the resistance for each pin of the connector back to the ECU.

Edit:
Note to self: Self, post the actual link, you muppet.
http://foxed.ca/rx7manual/2003mazdar...200100W03.html

Edit2: Another thought: have you smoked it out for vacuum leaks?

 

Change your air filter

 

Very common for a buildup of gunk around where the throttle sits against the throttle body . Give that a clean out ........... good chance that will fix your issue .

 

yes, its runs better with disconnected maf sensor.
where is main relay? i tested maf connector to ECU, its ok.

 

already cleaned.

 

unscrew spark plugs, its normal?

 

 

this spark plugs are new, runs 100 km.

 

some advices guys?

 

your plugs look filthy. you said you installed new coils right?

 

This coils
https://www.ebay.co.uk/itm/Ignition-...frcectupt=true

 

I could be wrong but I believe if you unplug the MAF sensor and the car doesn't cut off within 30 seconds or so, that means the MAF sensor is bad. Again, I may be wrong. I just know one time I forgot to plug mine in and when I started it it cut off 30 seconds or so later and my MAF sensor was good.

 

Do you have a scanner ..... It appears to be running abnormally rich by looking at the plugs. If you check the LT and ST fuel trims and look at MAF and O2 sensor data it might help. Other than that I would take it out someplace and drive the **** out of it and see if that helps.