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It's a 4. something
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Discussion Starter · #1 ·
So I was messing around with my truck this weekend. I have a code that trips because I don't have the A/C set up on the truck yet but I had Jared build my system for one. So the truck throws a code from it not being there.

While I was looking at the codes to make sure that was still the only one there, I decided to dump the freeze frame data and my fuel trims are WAY outa wack.

I need some help understanding what I'm looking at. I know that +- 10% is the max for what you wanna see. Here is what I have.

Short Term Trim 1 0.0%
Long Term Trim 1 0.0%
Short Term Trim 2 0.0%
Long Term Trim 2 0.0%
Short Term Trim 3 50.0%
Long Term Trim 3 -38.3%
Short Term Trim 4 57.0%
Long Term Trim 4 -45.2%

Throttle Position 9.0%
Engine RPM 1303
Load 4.7%
Air Flow Rate 10.67 GR/SEC
MAP 28 KPA
Coolant 82F

(I think it logged the code when I first started it judging by the coolant temp)

The short terms are showing lean and the long terms are showing rich and their WAY outa the thresh hold.

Also, what is trim 1 through 4. Is that split 1 trim per every 2 cylinders?
 

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It's a 4. something
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Discussion Starter · #3 ·
Yea I think your right about that. I've never posted over there but I'm gonna go check it out.
 

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trim 1 and 2 are the only ones that matter, bank 1, bank 2
 

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Hey just curious, what did you pull this from? HP Tuners? Or a code reader? Please update this when you find out, I will try to find it on tech but who knows.
 

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It's a 4. something
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3,980 Posts
Discussion Starter · #6 ·
A hand held code reader. Don't remember the brand.
 

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that's wierd having 4 seperate fuel trims... typically its just short term and long term for bank one and two, and you can pretty much disregard short term. Long term is what tells you what you need to know. (short term is just a quick change percentage off of the posted longterm number) positive numbers is a lean condition, negative is rich. and like you said +/-10% is an acceptable range. plenty of things can influence fuel trim so if you have any other codes present that could affect it address those and the numbers may improve. also i would not go by freeze frame data to get your fuel trims, you need to go out and road test the vehicle and look at the live data... that will tell you what your fuel trims actually are and if you have an issue.
 

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that's wierd having 4 seperate fuel trims... typically its just short term and long term for bank one and two, and you can pretty much disregard short term. Long term is what tells you what you need to know. (short term is just a quick change percentage off of the posted longterm number) positive numbers is a lean condition, negative is rich. and like you said +/-10% is an acceptable range. plenty of things can influence fuel trim so if you have any other codes present that could affect it address those and the numbers may improve. also i would not go by freeze frame data to get your fuel trims, you need to go out and road test the vehicle and look at the live data... that will tell you what your fuel trims actually are and if you have an issue.

I'd have to respectfully disagree with one thing you've said. The short term trims are just as important as the long term trims.

Long term 3 is -38 and the short term is +50 this nets a +12

Long term 4 is -45 and the short term is +57 this is a net +12
 

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It's a 4. something
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Discussion Starter · #10 ·
Thank guys! That helps a LOT. I feel like an idiot though. I didn't think about combining the short term and long term to get the final adjustment over the base. That makes sense thought because +12 would mean the truck is lean and it should because the fuel pump is acting up on it.

As for why it showed trim 3/4 instead of 1/2, who knows. Prolly just a cheap tool.

After I recover from the cost of the new transmission, I'll try to start saving up about $2000 for a laptop and hp tuners.

Thanks again for the help.
 

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Bowtie Til I Die
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You dont need that expensive of a laptop for hptuners. You could easily get HP Tuners Pro and a netbook for around $1000. Of course if you're going to be using the laptop for other things I could see you wanting something a little better
 

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I'd have to respectfully disagree with one thing you've said. The short term trims are just as important as the long term trims.

Long term 3 is -38 and the short term is +50 this nets a +12

Long term 4 is -45 and the short term is +57 this is a net +12
i understand what you mean. being it was freeze frame data that could mean that the longterm at some point during startup was -38/-45 and the pcm was in the process of rapidly adding fuel which would be why the short term was registering +50/+57... but to be honest i would not go by those numbers at all. just on the fact it was at startup and is freeze frame data. Live data after the engine is at running temp will tell the real situation.
 
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