Retune VE after injector upgrade?
Staging Lane
Joined: Nov 2015
Posts: 96
Likes: 0
Staging Lane
Joined: Nov 2015
Posts: 96
Likes: 0
Since you've yet to see a car that's even within 10, I'm attaching a log of a car that I'm in the process of tuning. It's an EFILive log, so I'll also attach the csv... if you don't have EFILive, then you can drop the csv into a spreadsheet and view it that way.
I asked the customer for a good mix of driving and about 12,000 frames of logging... and that's pretty much what I got. There's a good range of RPM and MAP values there... obviously he had to keep the car out of power enrichment, so you can't expect every RPM and MAP value to be covered. Long and Short term fuel trims are both logged, and you can see that the long term trims never go near 10. In fact, the worst long term fuel trim in that log is 3.9, so yeah... +5/-5 can realistically happen.
Long and Short term fuel trims are both logged, and you can see that the long term trims never go near 10. In fact, the worst long term fuel trim in that log is 3.9, so yeah... +5/-5 can realistically happen.
I was talking about tuning with purely short term trims and having the long term disabled, should have mentioned that. So just a different perspective as I don't like tuning with both enabled since LTs are too slow and leaving them enabled affects STs. In that sense, I've rarely seen ST trims only be within +10/-10.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Retune VE after injector upgrade? I wake up and see all this stuff happening...
I communicate with statesman often, he tunes a lot, and has a lot of related knowledge (check his posts in this forum where he helps people to get their cam to idle properly)...
getting LTFT's well within +/-5% is no big deal, you just have to meticulously take care of various things.
And a SD tune done properly won't be affected by weather... and conversely a MAF tune done poorly will be easily affected by weather.
I communicate with statesman often, he tunes a lot, and has a lot of related knowledge (check his posts in this forum where he helps people to get their cam to idle properly)...
getting LTFT's well within +/-5% is no big deal, you just have to meticulously take care of various things.
And a SD tune done properly won't be affected by weather... and conversely a MAF tune done poorly will be easily affected by weather.
Ah you're talking about long term fuel trims. With those enabled yes I agree that withing +5/-5 is reasonable...heck I've seen within +3/-3 sometimes.
I was talking about tuning with purely short term trims and having the long term disabled, should have mentioned that. So just a different perspective as I don't like tuning with both enabled since LTs are too slow and leaving them enabled affects STs. In that sense, I've rarely seen ST trims only be within +10/-10.
I was talking about tuning with purely short term trims and having the long term disabled, should have mentioned that. So just a different perspective as I don't like tuning with both enabled since LTs are too slow and leaving them enabled affects STs. In that sense, I've rarely seen ST trims only be within +10/-10.
Staging Lane
Joined: Nov 2015
Posts: 96
Likes: 0
Yes, you probably should have mentioned that. The OP said in his original post... "Both LT and ST fuel trims occasionally hit 13s". You then quoted that exact line and asked him if it was average or max. Anyone reading that would see you and the OP are both talking about long and short term fuel trims.... including the OP himself. The OP could have easily been misguided into believing that his fueling was good as he was talking about LT and ST fuel trims... not purely short term trims.
Last edited by statesman; Apr 10, 2016 at 08:51 AM. Reason: typo
