Well I got my hands on a Cobb Accessport 2 days ago. So I "installed" it and loaded the Stage 1 map. Went for a test drive, let the car warm up first ect. Then tried some WOT pulls and observed the AFR. I saw 14's, 15's and even 16's at high RPM.

I thought maybe the sensor was faulty so I loaded the stock style map on. I then drove around for a bit and did the pulls again. Now I observed low 11's which which was what I was expecting.

My car is 100% stock at this moment. Nothing is done to it at all. I would assume the Stage 1 map should be safe if the stock one is fine but it isn't. Any ideas?

Of course, I plan to be tuning this myself and even have the AccessTuner Race but the Stage 1 map being off the charts has made me stop and find out why it isn't working as advertised before I start messing with anything else.

Also, whats with the 66.69% throttle at WOT?

thewird

 

Wide open throttle position does read as 70%, I guess once your foot is that far in, the ECU sees no difference......the plate is wide open though.

 

Those are weird numbers. I've been running the Cobb tune for a while now, and it always gets rich when I lay onto the throttle. Your first experience might have been your car re-learning the tune after you reflashed the ECU.

 

I drove around for over 3 hours before with a few shutoffs on the stage 1 map before the log was taken. Also, I don't think it needs to correct for WOT as thats running open loop (I could be wrong about this though).

With both maps, the car tries really hard to stay at 14.7 in closed loop except at idle which is 15 but I assume thats the air pump since I don't think its actually idling at 15's. Haven't had time to pull the airpump fuse and testing it.

thewird

 

Idling at 15 is normal for that map. As far as I could gather from other threads, 14.7-15 is normal when you are at idle, and it should drop all the way down to 11 when you get to WOT. That is the range it should stay in for the Cobb Stage 1 tune. It should not be detrimental to the engine (besides burning a bit more gas at WOT for being so rich).

 

A rotary will not idle at 15 AFR smoothly if at all. I'm pretty sure thats an inaccurate reading caused by the air pump.

theiwrd

 

I'm unsure then, as mine idles just fine. I brought it up to attention before, but most people were worried more about the higher load areas. I'd be interested in what you find out then

 

Well at this point I'm more concerned about the WOT area AFR's too. I'll get back to yah when I get a chance to pull the air pump fuse .

thewird

 

Oh, just for our sake, copy your values into an excel sheet. The txt format is quite difficult to read!

 

Just rename the file to .csv instead of .txt . Or you can open as an exel file. I had to change it to be able to upload.

thewird

 

Yeah, looking at your stage-1 log, it's weird to be 13-15 at 100% load at those rpms.. has it settled down now in that upper region?

 

I'm running stock map pending resolution :P. I was running the Stage 1 for a while and the AFR's under load never changed.

theiwrd

 

My idle is set for 15:1 and it runs just fine. Some motors don't react well to lean conditions while others do. I can run my own motor (cruise values) as high as 17:1 before it starts sputtering because it can't produce any power. I've seen other RX8's that get fussy at 15.5:1.

For most RX8's the COBB stage 1 is very lean. I wouldn't suggest anyone use that tune even if you have the modifications listed for it.

 

That does sound odd . If you try it again also monitor your STFT and LTFT .

The air pump should only come on when engine is stone cold - I doubt it has anything to do with the issue .

 

just like brettus said air pump only comes on when cold, if there was a issue with the air pump you would most likely get a DTC code p0411

 

The short term fuel trim was taking away 0-3%, LTFT was unchanged. It did this with the stock map too. To my knowledge the fuel trims don't affect open loop though so it shouldn't matter.

Pretty sure the air pump is what makes the idle 15 AFR. To my knowledge cat's still require air to stay in operating temp at idle :P. If you've tuned rotaries before, the idle starts becoming unstable higher then ~13 AFR. The turbo RX-8 I tuned with the interceptor-X was no exception.

I'm not suggesting there is anything wrong with the air pump. I was merely stating an observation I made for idle until I realized what the cause was.

thewird

 

Yes they will

nope . It would be way higher if the air pump was on and the engine was warm .
+ you would hear the pump .

15.0 is fine for idle on the Renesis - although it does idle better if it is richer . The int -x was notorious for requiring a very rich idle due to other constraints it has.

 

Could we stop talking about the air pump?

thewird

 

sure - LOL . But you keep bringing it up ............

 

thats because you were using the int-x....idle always sucks with it
completely different when using MAF vs. MAP

my idle is rock solid at 14.7 AFR on my turbo 8 using the accessport...better than stock

 

 

Because MAF vs MAP makes a difference with AFR... sigh...

thewird

 

thats not what i meant.....i'm not going to get into this...

 

no - because the int-x does not have good enough control of idle to run any leaner than 13 - whereas the stock computer - does .

 

qft
thanks brettus