Gut or remove your cat immediately before it destroys your petite engine. Tuning mistakes can and will make it go faster.

After that i think you would be better off setting your injectors to stock then scaling the maf to les than 5%. Hunting 0 is a game you will play forever. Start easy then as you learn start dialing it in.

 

I've got an update on my situation guys.

New motor was put in last week, picked up the car today.

As soon as I got it home I logged the idle and checked the intake vacuum.

Vacuum was the same, sitting at a solid 14 inches of mercury. This is at nearly 5500 ft elevation.

My Baseline MAF Voltage is 1.063 V at 823 RPM, with an Airflow Rate of 3.74 g/sec. Adjusting for 5500 ft (about 17% low) puts me at an equivalent "sea level" flow rate of 4.56 g/sec.

So, I am still about 20% low compared to the 5.5 g/sec that Kane is used to seeing.

Just an FYI

 

5-5.5 g/sec.

So I don't think you're too far off.

As for Bob, average the three days worth into one matrix. Then don't worry about chasing anything less than 3% off. Chasing zero will drive you crazy. I bet you'll be surprised how close you are. And def get rid of the cat ASAP if it's showing signs of being toast.

 

Kane, do you have people scale the maf to get the desired g/sec? Or was that a misunderstanding that that is what you normally see?

 

I do. 5 to 5.5 g/sec.

This is because otherwise you don't have control over a single variable as you move through the tuning process.

 

If its out of that range wouldn't that point to a problem that should be addressed?

If you are just hunting that number then it is masking a problem that could throw the whole tune off.

 

Yes, that is why Hydronium and I were trying to figure out what is going on. You never assume that tuning math can fix a problem.

Typically if it is out of that range, it's due to an Intake that varies from stock.

 

Ok i don't think i interrupted you and Hydronium. I was following with a little interest. It sounded like Bob the Eskimo was blindly adjusting to 5.5 and i told him thats wrong but i wanted to make sure i wasn't contradicting what you were telling him. I understand adjusting air for pressure but that doesn't seam right when the engine is under a vacuum. I realize the air is thinner but it still requires a certain amount to generate the power required at idle(ie5.5g/sec). So the throttle plate would open a little more allowing the extra air in. The psia in the manifold should be about the same as at sea level. In fact i would think the psig would be the same also. If the gauge has not been zeroed in the local environment. Wouldn't it be better to test vac in the manifold then calculate the difference based on that.

 

Ideally yes. A vacuum gauge plus an airflow reading would be ideal.

It was just an interesting question (altitude) that I had not encountered yet.

 

If your LTFT at idle is stable ............... why chase 5.5g/s ?

 

Because that is how much air a RX8 motor flows at idle.

 

I have a vacuum gauge, I see 17 inHg at idle of 5.5g/s

 

What altitude are you at carbon?

 

400ft

 

Before I go any farther, a few housekeeping items.

Kane, thank you for posting the tuning class videos. It's a huge help for novice tuner's like me, and the aim small miss small theory makes me confident I won't destroy anything too badly.

Kane et al: thank you for the feedback and assistance. A little education and some tinkering goes a long way.

I went back to stock again and logged 1500-4000 just for ***** and giggles and everything seemed waaay out of line until I noticed something that makes a huge difference. The MazdaEdit software has several different Short term fuel trim sources (eg. O2, B1, B2, OBD, etc.). Most of the STFT monitors don't log anything at all. I've been using the STFT B1 OBD as shown in the picture below to tune my previous changes. These numbers range in the 10-15% off range frequently which led me to 9% MAF and 6% Injector 1 changes. However, when I logged the O2 STFT line (as seen in the pic) I get much more normal/reasonable changes. Perhaps I've been logging the wrong STFT in the past and making changes that didn't need to be made. The crazy part is that they both drop to 0% in Open loop.

Can anyone provide guidance as to which STFT I should use? I'll post this question in the MazdaEdit thread as well.

Pic Descriptions:
MAF stock O2 = using the newly found STFT O2.
MAF Stock = using the STFT i've used thus far in the tuning process (I now think is the wrong one.
ME log categories = shows the categories I have logged on runs, and the two different STFT columns.

 

The other day my accessport screen stopped working. Called Cobb, they said it would be $25 to replace the screen. Sent it in to them, they called today and said they went ahead and upgraded mine to a V2b, replaced the screen, and are including a new OBD2 cable.

Absolutely did not expect that from this Company.

Anyways, I should be back to tuning soon! Just wanted to post to let everyone know about the level of service Cobb is offering.

 

I also just Recently had the same issue with my Accessport screen burning out. Cobb fixed it for me for free and did so very quickly. It should be at my door tomorrow.

 

Started tuning this week, loaded my basemap with my injectors changed per the flow testing results Bank 1 400, Bank 2 & 3 418, no other changes yet.

Idle Logs, surprisingly everything seems right on without any adjustment.

 

Am I correct that for idle you want your LTFT and STFT to average out to 0?

 

Yes

 

+ or - 3%

 

Looks like Bank 1 needs a 3% decrease on cruise logs.

 

Am I chasing my tail on this one?

Also are my LTFT supposed to be almost 0, or does that mean I did not wait long enough after the re-flash for the fuel tables to compose before logging?

 

Your needed changes are so small, I'm thinking your mostly chasing your tail.

Under 3% is fine. Statistically it is almost perfect.

 

Thats what I was thinking.

What about my LTFT, normal for them to be near zero in closed loop?