I'm trying to setup the injector scaling/latency and fuel trims on my tune and was following Merlin's guide (new injector setup method #2 on pg 71).

My logs were showing low and mid trims of -11 and high trim of -8, so I thought I better scale my injectors properly and get it sorted.

The problem is the trims don't seem to budge regardless of the scaling settings I went and drove the car at cruise for about 20mins, then checked the settings and made some changes to scaling (increased injector scaling as per Merlin's guide). Drove for another 20 mins, but the trim values had not changed.

Any ideas what I'm doing wrong? I am running Power Enterprise TL700cc injectors. For this log, I started with injector scaling of 609 and logged for about 20mins:
EvoScanDataLog_2010.08.31_609cc.zip

Then I stopped, checked the logs and upped the scaling to 665 and uploaded to the ECU. Then logged for another 15-20 mins and got this:
EvoScanDataLog_2010.08.31_665cc.zip

Here's my ROM and xml definition (running 90550001 with Tephra v5.1)
Eisen7_90550001-v5.10_260810new.zip
90550001(tephra5.10).zip

Any help much appreciated

 

I can't view at work, but make sure to disconnect the battery between each scaling and latency change so that resets the fuel trims. Also make sure that the rear O2 sensor is still enabled in the periphery bits (if you have one).

 

Doesn't a minus figure mean you have to scale the injectors smaller? It's taking fuel out to maintain 14.7 AFR so the injectors are set to big?

 

Yes that is correct, when the fuel trims are negative you need to take away fuel and when they are positive you add fuel for the latencies, but if you are changing the injector scaling number then the lower(adding fuel) number is richer and the higher number is leaner(taking away fuel).

This thread has a ton of good info in it https://www.evolutionm.net/forums/ec...upermerge.html

 

Oh yeah, that'd be right. OP are you using a scaling that says "Injector scale +10%" ?

 

Thanks for the information guys

I think I have worked it out. In my logs, you can see my 'O2 sensor' is sitting on 4.9776 the whole time. It doesn't change... I did notice the 'O2FeedbackTrim' is moving around though. Not sure if that means anything?

I checked for error codes and there was a P0130 there. 'Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 1)'. Does this mean my front O2 sensor in the O2 pipe is dead? It's only about a month old!

The JDM Evo 7 only has one O2 sensor fitted (front) the rear one is an LC-1 in my case and is not wired into the ECU. I am logging WDB via serial into the laptop.

As for my injector scaling method - I just picked something close to my 700cc rating from the 'Scaling and Latency Examples' table on Pg 68 of Merlin's guide. Then under 'New Injector Setup Method #2' on Pg 73, he talks about logging a car that 'wen't way negative and hit -10%. So we pulled over and incremented the injector scaling from 552 to 573 (+3.5%).'

I was simply following his guidelines that going way negative on trims meant increasing injector scale Sounds like he's got it the wrong way round!

 

I would try resetting the code and see if it comes back. Can do that with the tactrix cable and evoscan. Also I would double check and see if the connection to the front 02 is broken anywhere.

The STFT (02 Feedback trim) Will bounce around during cruise and idle as it is trying to maintain a 14.7 AFR.

 

OK thanks will give that a go. Will also scale my injectors to a slightly lower amount to be safe. Would rather a bit rich than lean!

Failing that, I guess it's time to order another O2

I've definintely noticed the cold start is too lean because of the AFR's showing on the wideband and also the car jerks around a bit when cold. It wasn't doing that a few days ago on the same injector settings. Must be the O2 not doing the right thing and giving feedback.

 

Yeah definitely sounds like an issue with your 02 sensor. You could always do the https://www.evolutionm.net/forums/ec...o2-system.html mod instead of buying a new 02 sensor.

I don't know to much about the older Evo's but is the 02 sensor a 4 wire or a 1 wire sensor?

 

Hmm interesting link. Thanks for that. I think I'll try and get it all working with the narrowband O2 first though.

My front O2 is a 4 wire one. Plumbs into the O2 housing (mine's an Invidia).

 

Do I need rear O2 sensor too coud calibrate the injector scaling ? :O My rear o2 turned on in the periphery bits but I'm logging the wbo2 on this chanel with v7 9653.
Coud be this a problem ?! I have no any stock rear o2

 

yes but with wbo2 and this patch can we give real fuel trims like with the stock front o2 ? My car have no any o2 sensor and now using the wbo2 and the patch as you mention with great idle and afr ( 14.7 at idle as in the fuel map ) .

Do we really need the stock front ( and rear ?!?! ) o2 sensor when calibrate the new injectors with the help of the fuel trims ?!

 

Okay then in the tephra mod options, just check the rear O2 simulator option to make sure...

Also since you are getting a code for the front O2 that may be the problem...

 

okay so if the rear o2 is simulated than it is ok ?
Maybe do you know the answer for my post #12 ?

 

That patch allows you to use the wideband as the primary O2 sensor for fuel trims.