lean conditions light load, MAP sensor selection,

[Will guthrie]

Hi There,

I have a weird lean condition occurring with very slight light and gradual throttle opening increases I'm getting a lean condition even when the ecu is operating in already tuned cells in the fuel map. generally the car operates pretty well and the AFR sites pretty close to the target AFR I have set. but as I slowly increase the thottle it will go super lean for maybe a second or so.  Seems fine if throttle position rapidly increases Acceleration enrichment seems to do its job and ensure there is plenty of fuel on hand.

I have tinkered with a few things like charge temp aprox table and IAT fuel trim tables to try and fix it, as I thought it was from a heat soaking IAT sensor ( helped a tiny bit, but didn't solve) 

I've changed it over to the fuel modeling / VE system ( to exclude the MAF) and have a Link 3 bar MAP sensor  

 

My 1st question is: How fussy should one be? as this only occurs during light throttle opening areas. generally the AFR do get a little random in the very low load areas, is this normal? or perhaps evidence there is an issue? 

My 2nd question is: can a smarter human sanity check my trigger scope? that's some tech shit! although car runs fine.

my 3rd question is: I have the Link 3 bar MAP sensor, but don't have the option of a link MAP sensor in my sensor type menu. Seems to be working on the 3bar GM setting tho. I did the MAP sensor calibration, and it seemed happy with that.  Q= is that ok?? to have link sensor selected as a GM sensor?? 

Car is a Version 3 WRX STI with G4 + PNP ecu 

reading AFR off AEM wideband mounted in the downpipe

Thanks heaps in advance for any help anyone can offer. PS this is my first time tuning...

PS super stoked on the product! 

Log 2021-03-28 7;28;59 pm.llg Trigger Scope Log 2021-03-28 7;29;39 pm.llg gy and back no fuel.pclr

[dx4picco]

Is you map sensor now connected directly to the intake manifold? 

Or is it still like stock with manifold -filter - solenoid -map sensor? 

It may be adding a small delay in map signal that causes this issue. It least I have experienced an improvement in that regards after pluging the map directly

[Adamw]

You are on very old firmware which is why there is no Link 3 bar calibration, we have only been making those sensors for a couple of years but your firmware is from 2016.  However, I just compared calibration to the GM3bar and it looks very similar so that should be fine.

However, I would strongly recommend bringing firmware up to date as there have been many improvements and fixes since 5.6.1.

I think most of your "lean spot" is due to a lack of accel enrichment.  There is only one small spike of accel enrichment in your whole log when you mashed the throttle to the floor, for all other throttle movements there was none.  Your deadband at 2.5% is way higher than I normally use - this is highly variable from engine to engine but I most commonly end up somewhere between 0.2-0.6%.  

 

[Will guthrie]

Argh I see! I will definitely get the firmware sorted. and the accel enrichment ! awesome.. I thought it was only for the full throttle mash times...hence the increased deadband. I'll reduce this back down. 

As for the Map sensor routing, Yea I did end up plumbing it straight to the manifold, found an old vac port near  the center most point. Although I did have to think about all the other stock stuff in the stock map line..  A bit of googling and I came to conclusion I didn't need it for my application.  Map straight to Manifold..

Thanks for the help! very impressed with the support.