Optimising Your Tune Using Short & Long Term Fuel Trims (STFT + LTFT) [GOLD WEBINAR LESSON]

[@hpa101]

✅ Building a fast car? Get $400 OFF the all-inclusive VIP online course package deal: hpcdmy.co/vipy115 🦵Kickstart your EFI Tuning knowledge. Get 50% OFF your first online course: hpcdmy.co/offery115 TIMESTAMPS: 0:00 - Introduction 0:30 - What are STFT and LTFT? 1:10 - Wideband vs narrow band 3:50 - Pros and cons 6:10 - STFT + LTFT or STFT only 10:35 - How to disable LTFT 12:15 - Understanding GM ECUs - SD vs MAF 16:45 - What you should aim for 19:15 - Driving techniques 20:00 - Demo of SD histogram 33:25 - Demo setting up MAF histogram 39:30 - Questions

[@popomomo12]

Thank you guys, this is an example for me of how I continue to learn from these lessons. I always thought factory A/F sensors were good enough to use!😰

[@CorruptInfinityOfficial]

popomomo12 yeah not all factory a/f sensors are created equal, many random cars use wideband that you wouldn’t expect to

[@25aspooner]

Thank y’all for the awesome videos! Keep it up!!!

[@enhancedphysique6452]

Just look at the adjusted AFR. That a narrow band Will be correct.

[@ولدزايد-ذ2غ]

Hi I hope you’re fine so how edit all important tables when disconnecting A/F O2 sensor and car working on openloop and what important tables names needed to change in openloop conditions

[@Domas64]

I'm tuning on the road going horizontally through the cells instead of vertically as on the dyno. Trying to hold steady MAP reading that is on the map axis and go through the cells as rpm increases. Doing 1500-4000rpms in 5th gear for better accuracy and then 4000-7000 in 3rd. Do this several times and adjust VE table from logs or LTT table. Then interpolate values and proceed to the next row. Is this a good way to tune on the road? Thanks!

[@salvatorehayes2753]

Would It Be Weird To Only Use Long Term Fuel Trims? The Long Terms Take A Long Time To Set /Learn Which I Feel Like Would Be More Accurate Filtered Data. The Only Time I Use Short Term Fuel Trims Is Only In Areas That Are 0 Logged Long Term Trims Which Indicates I Haven't Hit That Cell Long Enough Or Is Dialed In Really Close (I Log Both Short And Long On Thier Own Tables). Then If The Short Term Has A Fair Amount Of Hits I'll Use That. I Don't See How LT+ST Is Accurate Because When A Long Term Sets At Say +20% The Short Terms Will Zero Out And Only Cycle +-5% From Zero. So The Short Terms Would Start To Bring Your ST+LT Trims Closer To Zero Which Is Inaccurate Especially Since ST Counts Are Significantly Higher Then LT.

[@AtticAZ]

What would cause a Speed Density car with a ProCharger make STFT’s go plus 15% Bank1 and 24% Bank2 at wide open throttle, in your opinion? Everything is in spec other than at aggressive throttle or WOT.

[@corvetteZ3r]

They turn off at WOT

[@TheLifeofaMan]

What about all the Knock restart that was popping up almost every data log?

[@hpa101]

For this particular lesson we were only focussing on the fuel delivery. The PCM was running a stock spark table which will often show knock activity as demonstrated. As part of a complete tune we would address this too but here we're only focussing on fuelling. The level of KR seen is not going to cause any damage under the load and rpm used for this webinar.

[@stevenmckeagg8113]

Thanks for the awesome video 👍, If the car your tuning came with a "wide band" O2 sensor from factory, would this be sufficient to dial in your power enrichment?

[@hpa101]

Provided the wideband is in fact accurate then yes. A lot of the factory wideband sensors tend to read inaccurate as we get further away from stoich and are really only used for closed loop control at stoich.

[@briansturgill5905]

Getting perfect STFT and LTFt almost 0 on both. When I come up to a stop light STFT go to +25 then couple seconds go back to right around 0. Then CEL for both banks lean will trigger. This only happens when I’m running the AC coincidentally. So frustrating.

[@minilogoguy18]

A/C adds a mechanical load to the vehicle. The car will not be in the same load cells on the fuel map as it is with the A/C off. You need to move a few columns above the idle area in the fuel map at the same RPM. You also need to make sure the fuel injector dead time is set correctly for the change in system voltage.

[@ولدزايد-ذ2غ]

How edit A/F O2 sensor table in HP tuner when disconnect O2 wires and car works in openloop and what other table needs to edits

[@p3anutz69]

it is nice to help or camutiy

[@VR6NAVYVW]

What about for instance in my Hondata S300 that uses a wideband for closed loop? It is a setting in closed loop tab to use a wideband.

[@hassanabas1549]

So stft and ltft is a perfect way to use if you want to just tune for best mpg for your car ☺

[@hassanabas1549]

Well if this is the best way to tune for best mpg which is more accurate to log with stft ltft ratio or stft on a table on its own and ltft on another table on its own?

[@hassanabas1549]

4 days and he didn't see my comment I need an answer

[@Garreslittlefarm]

Installed a 6,1 Camshaft in a 5,7 Hemi dodge ram 1500. Afer running it for a bit the LTFT is at -25 ish. Both banks. I have no tune in my truck. STFT is close to zero. Is the 6,1 camshaft the reason for the negative LTFT ? Do i need a tune ? Thumbs up for the webinar :D

[@hpa101]

I don't know the specifics of the cam swap you have done, but if you're not swapping a like for like cam regardless of the engine, yes, you need to tune to suit to let the engine know what the changes are and get the most from your modifications. Trims are only compensations based on the original tune which was done to suit a configuration of parts you no longer have. The ECU won't retune itself to suit such changes in air flow. How good would it be if it could though eh! Do the other basic checks since you have been poking around there too, such as checking for vacuum leaks too. If you plan other modifications in the near future you might want to do them now before you get your tune too so you can save yourself a bit of money and just get it tuned the once - Taz.

[@general23cmp]

Does the PCM have an internal VE-type table that it stores LTFT values based on RPM and load, or is a single LTFT number applied across the board?

[@jeffreydurham5342]

I know gm pcms use a table, you can see what cell you're in on the scanner. Hope this helps!

[@mujtabapolani3229]

Hello dear my Ltft always stuck in single value

[@johndoe-zd9lb]

just so i understand, this maf correction table (ltft+stft math + mass frequency) is used in closed loop operations with the stft and ltft's enabled(so you can even get a reading on the trims)....how do you keep the dynamic airflow tables utilizing speed density from skeewing the maf data (which is what i'm trying to tune (maf only))? i'm familiar with the other method of using eq error ratio math + mass frequency in open loop with speed density/stft''s/ltft's all disabled .....that makes sense because you block those tables from skeewing your maf data?

[@leroyhart1368]

You need to disable the Dynamic like the other EQ error method.

[@SB-qw8bz]

So MAF & LTFT has to disabled?

[@TheLifeofaMan]

Seriously...that was not a negative comment that was a for real question why was the tons of KR in the scan?

[@hpa101]

Replied to your other comment ;)

[@isidrosevier1125]

Sometimes you get kr on downshifts. Sometimes it could be false knock

[@franchise-pj6ow]

Why doesnt anybody show how to tune hemi engines ? What path would one take for tuning a 3rd gen 5.7 hemi with NN on or off ?

[@elyasrasti8943]

What the hell is the difference on a hemi engine? Explain to me how your hemi uses alien technology that is radically different than every other combustion engine on the planet.

[@nottobay6768]

@@elyasrasti8943 bruh it's just a high compression v8 with 2 plugs per cylinder, there's no special black magic going on.

[@elyasrasti8943]

@@nottobay6768 that's what I'm saying. Dude acts like he's the only guy with a different engine in the world

[@nottobay6768]

@@elyasrasti8943 yah, it's not like it's a rotary or possibly a boxer that actually are a bit special.

[@maxdabator]

can you PPLEASE do some barra tuning

[@hpa101]

Unless you're tuning yours using something other than the Speed Density Principle, we literally already have hours and hours of content that applies to them and a few 1000 other odd engines 😉 Even then, SD isn't the only tuning principle we cover either 🤘 - Taz.

[@maxdabator]

@@hpa101 okay I’m just useless at it then :/ Hard to find info for a beginner on them

[@hpa101]

Have you taken the EFI Tuning Fundamentals course? If you are struggling with getting started tuning, I think it will fill in many of the blanks you have to be honest: www.hpacademy.com/courses/efi-tuning-fundamentals/? If you have done it and are still struggling to get some traction, jump on the HPA members forums with some questions my guy, it's what it's there for 🤘 - Taz.