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Discussion Starter #21
Map sensors should read 0 when KOEO. Im at sea level and ill double check tomorrow on mine. The more we talk just tells me its wrong. It should read about 25/30% less then vacuum while running at idle no load. 5 is not a good # at idle.
Ok, and after looking at a log from my brother's truck that I know is running good, his idle map is about 8psi
 

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Map sensor should read baro with KOEO.
997075


Don't forget that ambient conditions (temp, humidity, baro pressure) are why fuel trims change from one day to the next. If your tune is with NN on (how most tunes are set except for big cams where the stock algorithm is not able to use the stock torque/air model to keep the engine running due to the drastic change the cam creates) then all that can be done to correct fueling at PT is to log fuel trims as a function of injector pulse width and use the average to sort of "scale" the injectors. If you do this when temps are cooler then fuel trims will be negative if the next day is warmer.
 

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I see the issue. My scanner is set up to look at the vacuum and yours is looking at kpa. Ill go into the settings and see if i can flip them over to kpa and get what mine reads for you to compare to.
 

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BTW negative fuel trims mean the PCM is trying to pull fuel. If you had a leak in the manifold the PCM would try to add fuel to keep stoich with the extra air it is seeing.

Clear your adaptives and see what the fuel trims do. To be honest if you LT trims are within +/-10 your fine. There are guys that drive themselves crazy to get fuel trims to within 5% only to see the next day there are >5%.
 

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Discussion Starter #25
Map sensor should read baro with KOEO.
View attachment 997075

Don't forget that ambient conditions are why fuel trims change from one day to the next. If your tune is with NN on then all that can be done to correct fueling at PT is to log fuel trims as a function of injector pulse width and use the average to sort of "scale" the injectors. If you do this when temps are cooler then fuel trims will be negative it the next day is warmer.
See that's what I was thinking, when I originally got this tune I was logging ambients at ~60°F and lately it's been 85-95°F and my LT FT are staying around -20 to -25 at PT. When it was cooler they weren't much better tbh at around -15 but the car seemed to drive fine and tuner said they looked good.
One good thing from all this logging I've been doing is I caught a bad tank of gas, I hit 9.5 degrees of ST Knock and 1.5 LT. A little VP octane booster got it back down to 0 tho.
 

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Discussion Starter #26
BTW negative fuel trims mean the PCM is trying to pull fuel. If you had a leak in the manifold the PCM would try to add fueling to keep stoich with the extra air it is seeing.
Yea also what I was thinking too but multiple people were telling me it's a vacuum leak or something. The only thing I haven't been able to check yet is fuel pressure but I doubt thats it. I finally found the log from the second to last revision I had and it actually looks very similar to what I'm running now. There was just one point I was at -29 LTFT for about a week but I reset the pcm and it seemed to fix it and bring it down to -22 again. I just don't get why he'd keep it at -22? Shouldn't it be +/-10?
 

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This is the problem tuning with NN on and using injector scaling to kinda cheat PT fueling. If you log and adjust the injectors on a cold winter (air is dense) day the fuel trims will be negative during the summer (air is less dense).
 

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Discussion Starter #28
This is the problem tuning with NN on and using injector scaling to kinda cheat PT fueling. If you log and adjust the injectors on a cold winter (air is dense) day the fuel trims will be negative during the summer (air is less dense).
What's NN? You're saying a lot of things I thought about initially but a few people told me it's definitely a leak or bad sensor or something so I decided to go with experience over my knowledge.
 

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As for your knock, it is pro
What's NN? You're saying a lot of things I thought about initially but a few people told me it's definitely a leak or bad sensor or something so I decided to go with experience over my knowledge.
Neural Network. The PCM uses an algorithm to adjust fuel/timing/VVT...etc based on inputs from sensors. There are VE (volumetric efficiency) tables but the PCM ignores those as it is using the algorithm (i.e. NN is on). If you turn NN off then the PCM uses the VE tables...which the stock tables are way off from what they should be. If you are using diablo then you never see any of this stuff as it requires CMR software. Below is a screenshot from HP tuners which gives you complete access to all tables/values that they were able to define.

997077
 

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FYI here is a great thread explaining how PT fueling is handed with NN (or ANN) enabled.

If you want to go further in the rabbit hole, here is a collection of links I have been keeping that help me understand tuning using HP.
 

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Discussion Starter #31
As for your knock, it is pro


Neural Network. The PCM uses an algorithm to adjust fuel/timing/VVT...etc based on inputs from sensors. There are VE (volumetric efficiency) tables but the PCM ignores those as it is using the algorithm (i.e. NN is on). If you turn NN off then the PCM uses the VE tables...which the stock tables are way off from what they should be. If you are using diablo then you never see any of this stuff as it requires CMR software. Below is a screenshot from HP tuners which gives you complete access to all tables/values that they were able to define.

View attachment 997077
I have both hp and Diablo so I'm a little familiar, but my tuner does Diablo only. I may mess around with the hp a little to see if I can get the fuel trims down. The knock was from a sketchy "gulf" station when I was gonna run out of gas. Local gas stations near me are notorious for having big name signs but not actually using the big name gas. Whenever I'm on shell my St knock never passes .5
 

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Discussion Starter #32
FYI here is a great thread explaining how PT fueling is handed with NN (or ANN) enabled.

If you want to go further in the rabbit hole, here is a collection of links I have been keeping that help me understand tuning using HP.
My brother bought all of those tuning classes they have for HP, but he's too lazy to watch it and pay attention.
 

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I have both hp and Diablo so I'm a little familiar, but my tuner does Diablo only. I may mess around with the hp a little to see if I can get the fuel trims down. The knock was from a sketchy "gulf" station when I was gonna run out of gas. Local gas stations near me are notorious for having big name signs but not actually using the big name gas. Whenever I'm on shell my St knock never passes .5
Use HP to read the tune currently on the car. Then load the stock tune with diablo and read the tune again with HP. SAVE these tunes on a USB stick and store it somewhere safe. You can then use HP to compare the tunes using the comparison log. I bet NN is on and fuel injector data has been modified. I personally don't think you have an issue, it is just the tune was developed during a colder portion of the year.
 

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My brother bought all of those tuning classes they have for HP, but he's too lazy to watch it and pay attention.
The tuning school course work for dodge is not very good and honestly there is more useful info on HP forum. Knowing what I know now, I would not have paid for the book. BTW there is no mention of how to tune the trans which is the other side tuning that is crucial...fortunately us manual trans guys don't have to futz with it. I recently decided to try pulling airflow tables from a member's tune (Hemituna...very knowledgeable guy over there) and the changes are not intuitive but dam is the throttle way more responsive. It's not perfect but holy cow the car drives like a beast. Problem is I don't do this for a living and once you step away from HP you tend to forget what table does what and how to change it to get the desired outcome.
 

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I have both hp and Diablo so I'm a little familiar, but my tuner does Diablo only. I may mess around with the hp a little to see if I can get the fuel trims down. The knock was from a sketchy "gulf" station when I was gonna run out of gas. Local gas stations near me are notorious for having big name signs but not actually using the big name gas. Whenever I'm on shell my St knock never passes .5
Heat soak tends to generate high intake air temps which can cause knock. Even running 93 octane can result in knock if timing is set a little aggressive. Also, even with a stock tune you will see some knock (maybe a degree or more) on a hot summer day in traffic...usually when you accelerate hard and not necessarily to WOT. If you want to see real knock then try running 87 octane. Did that when I first bought the challenger and did not realize the M6 version required 91 or better.
 

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So i hooked up the scsnner today and theres no way to change it from vacuum to kpa. All ive ever used is vacuum. I dont tune cars either and think it must be a tune software thing. Was raised to look at vacuum at the sensor and voltage readings. I diagnose cars and dont tune. Yall give me something to research and check out.
@ChallyTatum , what should the ltft's be on a stock tune? I looked at mine today, usually only use 02 data to diagnose issues. Curios about this.
 

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On my stock 5.7 jeep LTFT is usually around 5-10%. I have a recent log where I was stabbing the throttle to look at cam movement and LTFT was within 5%. As for manifold pressure the units don't really matter. Just need to remember that at KOEO there will be no vacuum as the intake sees atmosphere which is not zero if you are reading absolute pressure. I have always used vacuum gauges back in the day but now I am comfortable in using kPa because that is what the unit of measure MAP sensor transfer functions use.
 

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Ya im going to be stuck with still using zero and vacuum til i decide to buy tuning software. This is what i can see and use.
20200630_142512_HDR.jpg
20200630_142557.jpg
 

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Discussion Starter #39

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So i hooked up the scsnner today and theres no way to change it from vacuum to kpa. All ive ever used is vacuum. I dont tune cars either and think it must be a tune software thing. Was raised to look at vacuum at the sensor and voltage readings. I diagnose cars and dont tune. Yall give me something to research and check out.
@ChallyTatum , what should the ltft's be on a stock tune? I looked at mine today, usually only use 02 data to diagnose issues. Curios about this.
There is a different PID that gives pressure values in KPA, in fact there are a couple different PIDs you can log for pressure, depending on if you want absolute pressure or not.

I can’t remember the PIDs names off the top of my head, but they should be easy to pick out if you are looking at a list of available PIDs to log.
 
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