Hey Guys,

I put my car on the dyno today for the first time, I have tuned it myself and I noticed quite a decent gain in power. It is a Mirage with evo 5 running gear and an evo 7 ecu with a patched tephra rom. The car has an HKS intake and factory exhaust with no muffler, and no cat. Running 18psi peak @ 4400rpm and tapering off to 15psi by redline.

What I noticed is that the AFR values recorded from the dyno are way off from the values in my High octane fuel map.

my lowest AFR is around 11.0 @ 3000rpm and it goes up to around 13 by 4300rpm and stays just below 13 from there to redline.

I attached a pic of my current high octane map and you can see that it is not the case with my AFR map, I know it is just a number but I thought it would be atleast close...

I also attached an image of the AFR values according to the load cells I hit.

Why is my AFR on the dyno so damn far off the values in my AFR map?

Any help would be great, thanks in advance.

Martin.

EDIT: just added rough image of what AFR looks like on the dyno. Crazy lean!

 

How are your fuel trims looking? What injectors does the car have and what do you have the maps scaled to? From the size of the map it's a terphra V7, most likely 9653 it may still have lean spool on as well.

 

Also, I forgot to mention if I cruise at a constant speed for a while (say on the highway for example) I get the P0140 CEL - fuel trim malfunction (Bank 1).
I clear it but it eventually comes back on.

I am indeed running Tephra v7 with the 96532706 rom.

My injectors are factory 560cc injectors scaled to 513cc in Evoscan. Should I disable lean spool?

I havent touched any fuel trims, which one should I be looking at? Im not 100% sure what to do with fuel trims sorry.

Fuel Trim Low and Medium values are all -12.5 for all load cells hit
Fuel Trim High values are all 0's for all load cells hit

The LFTF in use and STFT tables from maptracer in evoscan are attached. How do I know what values I should be changing? How do I know what is acceptable?

Cheers, Martin.

 

You need to scale the injectors in ECUFlash. Look at the scaling for the injectors, if's "injector scaling" set to about 490, if it's "injector scaling + 10%" set to 513. You will need to do the latencys, start with the USDM Evo 8 setting to start with. Log trims low and mids trims in Evoscan if over -/+ 12% you will get that CEL.

 

-12.5 !? I was told you were supposed to be under +-5.0

here's what I had when I logged with evoscan on a real dyno the other day
fuel trim low +0.297
fuel trim mid -2.841
fuel trim high +0.101

which ones are you talking about ? the AFRs in the low revs or in the high revs ?
I mean I don't see the problem on your two first pictures
fuel map says 10.2@4000rpm-220load and you have 10.3@4000rpm-220load on the right picture.
I don't see where you have 13afr till redline on your pictures ?
But I'm new to tuning myself.

Also I was told several times that it was a known fact that octane fuel maps and reality don't match and mine definitely don't and by way more than you....
I had +- 1.2afr at first 10 instead of 11, 13 instead of 12 etc....
judging by your map tracer pictures it's following your fuel map pretty good..really I don't get what's your problem ?!?

 

If the OP has not yet scaled his injectors ( likely to be stock Evo 7 settings) then is fuel trims are hitting -12.5 % ( max you can get) He's not aiming for that, it's the logged value.

 

The ECU Fuel table does not match actual AFR. This has been stated multiple times over the years.

It's normal.

Make sure you injectors are scaled properly, your MAF scaling is correct, etc

Then just think as the AFR map as an additive/subtractive map, NOT a 1:1 to actual AFR

 

I changed the injector scaling in the 96532706 rom from 542 to 490, ecuflash sees it as 487 though.

Ive gotta problem with the MAF scaling. EDIT: figured the units conversion out.

 

Hey Guys,

Thanks alot for the valuable input so far.

To Kakihara:
Sorry for the confusion, a picture says a thousand words. lol. I just added a rough pic of what my AFR looked like on the dyno vs what the AFR in my fuel tables looked like. One is my AFR table, One is a log of load cells hit during the dyno run, and the other is the actual AFR recorded using the wideband.

I have read that the AFR values in the fuel tables dont match and I know that, I just didnt expect them to waaay off. For example its defined as low 10's~9.9ish by redline in the table but on the dyno its just under 13 at redline! Very scary...

 

UPDATE:

this helped alot with scaling my MAF table on the evo 5 rom.

https://www.evolutionm.net/forums/ec...hout-pics.html


The evo 5 MAF isnt that much different from the evo 7 MAF scalings, and lean spool was disabled from the start. Could the reason why it was so rich really be because of injector scaling set to 542 instead of 513 or 490?

Will try the new MAF scalings on my car tonight and let you know how it goes.