Whats up guys.
Have a evo8 rs.
E85,cam,fp red
Car was tuned on ecuflash on streets by my buddie.
Im a studying tuner for my own car.

Anyhow i started messing with maf scaling trying to smooth out the curve. Now i cant seem to get my afrs back in check. They will go full lean on my wb02. And my o2 sensor feedback stft is 24 and cycles to 16 and back to 24.

also low ltft and mid ltft go 12.5.

Ive tried and tried to get maf scaling back to were it was but cant seem to figure it out.

I have rom id if necessary.

Thanks in advance!

 

at the moment i cannot load logs because im on my mobile phone and have no wifi on my logging device.

My idle is rough when first starting car and my wbo2 is full lean ---- ill rev it a little and eventually let off and my idle afr goes to 14.7 ish. But when i go and drive i go full lean part throttle not even in boost. Soon as i get to 0 vaccum i go full lean and car bogs. This is not even passed 25 percent throttle id assume.

 

Do you have an old copy of the ROM so that you can replace the old values? That is, can you return to your baseline tune? DO you know if the stock ROM values were used or did your friend modify the scaling to perform the tune??

Did you reset the ECU back into learning mode after making the update?

Did you modify the MAF adder value at all?

 

silver2gst yes I have old rom and flashed it back but car still runs full lean in all areas. idle , cruise.

I only touched maf scaling no other areas of rom.

2d graph

left table is maf hz from 19-1610
right table is maf scaling + maf adder g/s

I only played with the right tables of maf scaling + maff adder.

No I didn't put it in ( learning) mode I am un aware of that sir.

Thanks for the reply

 

So you have returned to the baseline tune and are still experiencing issues? Then it must be something other then the MAF scaling, as you have reverted to values that were fine before.

Not sure if a flash clears the FMS learning values (such as STFT, LTFT ect) but you might try removing power from the ECU and start from scratch. The ECU will then be in learning mode and begin updating the STFT and LTFT (starting from 0 and 0).

Did you mess with anything other then EcuFlash?

 

Reset the ecu (disconnect the battery) this will reset the fuel trims on an Evo 8. Then try again.

 

so every time I make an adjustment to the maf I need to reset the battery?

Also when adjusting the right table maf does any other table need adjusting to counter it?

Is there a formula to create perfect numbers for 2d table?

 

Why are you adjusting this table? It seems like you don't have a good reason and you are just wanting to make it smooth? Why do you think smooth is the correct answer here?

This table models the MAF hardware response to incoming airflow. Its the relationship the ECU uses to understand how much air is ingested by the sensor at a given reported frequency on the MAF input into the ECU.

Unless your hardware (MAF) is different then what this table was set up for (like removing the honeycombs or some other hacks) it might not be the best thing to play around with.

Your tuning focus should be on the timing and fuel tables. Boost control if you are using that.

 

ronaldo9 confirmed what I was hinting at, on the EVO 8 it sounds like you need to reset the ECU. Every time I flash the ECU, I reset it afterwards just to make sure nothing persisted from the last tune in the volatile memory (think RAM). It wasn't clear to me if the act of flashing itself wipes out the volatile memory, but it sounds like it does not.

 

Will report back once I reset ecu and reflash it with original map

 

Thanks guys i figured it out. Obviously i dont know what the hell im doing. Some how my car went into my 91 map when i flashed the car. Maybe i missed it in all the reading ive been doing on ecu flash and evo scan. Switched my map back to 2nd mode and car is back to beast mode.

Thanks for the answers guys. 🍺🍺🍺👍🏼👍🏼


Atleast it is on the interweb now incase another self tuner encounters this mess.

 

Be careful buddy and glad you figured it out. The good thing about this community is practically everyone have encountered a similar problem or situation before.

 

Just to add a note here. You should not touch the MAF scaling at all. There should be a table caled maf compensation right below it. That is the table you adjust. I also did not see the ROM version you are using. Can you please post. Thank you.

 

tephra mod 9653076

 

This is the correct table to adjust to compensate for intakes, filters, etc. This table is an adder table. You literally just increment slowly, trial and error, until trims come into set, and boost section of fuel map starts to richen up and match numbers. This is suggesting that trims are already within the 5% tolerance, and are utilizing it to be OCD on trims. Of course cross reference your logs utilizing the AIRFLOW MUT2 mod in EVOSCAN, vs AFR at the Load for the sections or frequency area to change. ...oh, and only change the cell's in the right column for basic adjustments. Rescaling the frequency side of the table is a whole different animal, and for a whole different reason.