Quote from Rytari on February 21, 2024, 5:08 pm

I been trying to fix lean off idle issue, maybe its not a common off idle issue, but cannot say better name for it.

Mildly modified Chevy 4.3 v6  with 600 power adder, fitech control timing.

Idle is fine, 750 rpm and 14 afr, revving in neutral makes afr go a bit too thick, nevermind. Switching to gear and moving i have a nearly dead spot there below 1100rpm. it goes so lean that many times it sneezes to air filter, afr goes all the way up 20, accelerating a bit heavier it goes faster past it, i can see afr 16 and engine hesitates and stumbles and then starts moving. Sometimes it goes lean even  when i stsrt accelerating from bit higer rpm and speed, ~ 1200-1400 rpm, driving in town.

Then when driving and slowing down, coasting and letting engine come down to idle it will go lean, stalls and dies,  and usually will be hard to start again, of course this happens always when crossing a road or middle of intersection.   When starting again it will again idle just fine.

Im a bit lost here, truck is un drivable.

I did have open loop issue, my afr was solid 14.7 but i managed to tackle it by doing a full reset and cal reinstall 3 times.

I have tried so many things, cant even remember all, but i cant get it any better.  I did have accelration nearly maxed out, but it only did a rich condition after that lean spot so i backed down, in 3d table i still have maximum values in 800 and 1200 areas.

I have tried different iac opening, afr and spark settings, i have changed low map breakpoint from 45 to 65 and changed afr target in 1100 rpm even up to 12.8 to see if it helps to keep from stalling around that rpm.

Also my temp sensor is off and i cannot adjust it because im missing that table from hy handheld.

I asked help via email from fitech but i think my english is so lousy ot the just dont want to understant me because all they send is some generic how to files and links that wont directly point to my issue.

 

 

 

 

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