Do you see IAT having a huge affect on air/fuel? Same tune way rich one pull vs other

[GrannySShifting]

Havent poured through every table, but this LSA cammed car was previously tuned when I got it. First couple pulls, 2nd not exactly cold or anything made pretty good power, touch too much timing in it on pump gas for my liking (KR consistent) I fiddled around with it pulled a little timing but it was way rich with little no fueling changes so i put original file back in and its still wayyyy richer than it was the first couple pulls. IAT is higher but 20-35 degrees ive never noticed change airfuel much to talk about meanwhile this is 11.6 vs 9.6 a/f

Other than letting it cool all the way down and repeating the same pulls over again... i dont have a clue why its so drastically different

[GHuggins]

Tip temp open loop multiplier. Tip temp is directly affected by air temp. I'm actually surprised your fueling is staying close with the regular tip temp 0ed out. I would start with the multipliers and go from there. Probably want to verify injectors and data there too.

[edcmat-l1]

Both logs the commanded EQ and commanded AFR stayed the same. Fuel pressures stayed nearly identical also. Biggest difference in the logs is your long term fuel trims. On one run they were negative. On the other run they were positive 6.3 and 7.8%.

It also made 5 Kpa MORE through the entire run on one run than the other.

If you pick a spot, say 5300, the MAF values are nearly identical, putting the MAF in the same cell or two in each pull, yet the manifold pressure is more in one run than in the other.

I think that combined with the difference in your long-term trims is going to be the solution to the problem. They aren't 2 "identical" runs.

[Alvin]

It's not injector tip temperature..

Simple math. If you go to that correction table you'd have 0.1ms of offset

Injector DC for you at WOT is 11 ms so with that offset that would be 11.1ms That is a difference of 0.1% not 1% 0.1%


The difference between fueling is because the two runs have different LTFT's. A positive LTFT will carry over to WOT fueling. A Negative one will not.. SO if one run is +8 % which is pretty close to where yours is.. you'd get 8% more fuel at wide open. If the next run is -4% than you'd get no less fuel than normal. Only positives have an effect.


.

[GrannySShifting]

Tip temp open loop multiplier. Tip temp is directly affected by air temp. I'm actually surprised your fueling is staying close with the regular tip temp 0ed out. I would start with the multipliers and go from there. Probably want to verify injectors and data there too.

You mean injector Offset vs Tip Temp table? Yeah doing a compare I noticed they had zerod that out, but setting it back to stock actually had very little affect on fueling even with ITT at 140 degrees.

What did make a difference in consistency hot vs cold ITT and IATs was setting the IFR Modifier vs IAT table to all 1.0s. Ive never touched that table but Ive also not seen as much inconsistency pull to pull as thing car. Making 1 run and then another 5-10 minutes later and being 90 ft lbs down and 11.7 to 9.6 A/F is wild

[GrannySShifting]

I didnt pay attention to the LTFTs because I normally turn them off and use STFTs only!

That being said a 8% LTFT difference doesnt make it go from 11.8:1 to mid 9s air/fuel?? On later pulls when I zerod out the LTFT it STILL had some big fueling changes in back to back to back pulls.

Another odd thing with this car when I changed from pump93 and fuel trims were within 5%, on E70 it was pulling out -18 to -23% fuel at low MAF airflows but WOT the air fuel was actually leaner not much richer... Generally if one fuel is trimmed pretty tight everything is close no matter what the alcohol content but NOT this thing

[GHuggins]

You mean injector Offset vs Tip Temp table? Yeah doing a compare I noticed they had zerod that out, but setting it back to stock actually had very little affect on fueling even with ITT at 140 degrees.

What did make a difference in consistency hot vs cold ITT and IATs was setting the IFR Modifier vs IAT table to all 1.0s. Ive never touched that table but Ive also not seen as much inconsistency pull to pull as thing car. Making 1 run and then another 5-10 minutes later and being 90 ft lbs down and 11.7 to 9.6 A/F is wild

I've only ever seen the need to set that table to 1's on heavily modified lsa's, but usually by that point your running a heavily over driven blower on a stroker engine and having to use the individual cylinder multipliers to keep fueling right due to the eatons air flow issues, which is a HUGE pita cause you gotta pull, read then clean plugs every f'n pull...

Your trim change, changing with temperature is almost always itt related. I honestly didn't look at the log to know if you have a belt slipping or something like that as Ed may have been hinting at. I just glanced at the usual's I look for when someone mentions this going on in the cal. I normally set the itt open loop table to 1's, if it's going to be getting regularly run hard and then dial in the regular itt table based off of trim changes vs the itt.

[JayRolla]

Disable LTFT.

[smokeshow]

I've only ever seen the need to set that table to 1's on heavily modified lsa's, but usually by that point your running a heavily over driven blower on a stroker engine and having to use the individual cylinder multipliers to keep fueling right due to the eatons air flow issues, which is a HUGE pita cause you gotta pull, read then clean plugs every f'n pull...

Your trim change, changing with temperature is almost always itt related. I honestly didn't look at the log to know if you have a belt slipping or something like that as Ed may have been hinting at. I just glanced at the usual's I look for when someone mentions this going on in the cal. I normally set the itt open loop table to 1's, if it's going to be getting regularly run hard and then dial in the regular itt table based off of trim changes vs the itt.

Lol, STAHP. Not every problem is solved with that table. Few are, actually.

The overarching idea here is that after the injector temp model stabilizes after an actual hot soaked restart, temperature will be low enough that the multiplier will already be at/around 1.0. Until then, you probably need the multiplier.

And if anyone thinks that you should be adjusting for fueling error using closed loop trims after an ECM reflash, you are wrong and should not give out advice. ALL nonvolatiles are initialized to default values after a module flash, so there is no scenario immediately following a flash that should make you start changing fueling. This is standard practice all across Detroit, I assure you.

[GHuggins]

I know, I know Jake If you haven't tried it, it does work for dialing it in. You just have to use the right procedure.... The reason why I mention it often enough is because everyone got told some bad advice by others and started 0ing it out all of the time. That causes a lot of problems. I've dialed in many using the temp calc that the ecm is already doing during a hot flash and they always maintain trim errors and EQ errors with it dialed in. Again, as long as you do a hot flash and drive it the same afterwords - preferably at a cruise before and after - it works out... Now I whole heartedly agree that it shouldn't just be 0ed out unless the application and build just turn out that way

[smokeshow]

Can't tell if trolling lol. No. That is not a viable method.

[GHuggins]

May not be viable as in lab settings with a thermocoupler, but it works and it will correct fueling errors for the changing temps I've changed the method a little, but been more or less correcting it since 2017ish or whenever Scott found it. It works to keep trims in line such as where the OP's was adding 5% via lt's when it was getting hot to even keeping the afr's as commanded granted there are several other tables that affect the open loop portion. Not trolling. Your the one that said I shouldn't be giving advice I could go on and on with proof but what's the point. I respect you and your info, it's just this is how I find it easiest to dial it in even if it's not supposed to work. Now if you know a better table for correcting the fuel error for the very high temps that some of these back to back beaten on cars see, I'm all ears. Blown cars often enough see 100 to 110ish C being hot lapped. I don't mind them getting richer, especially that hot, just don't see the point in them shifting super rich especially on torque sensitive setups.

[smokeshow]

You don't calibrate for fueling after controller init. Period.

What do I know, I only do engine and precision controls for a living lol.

[GHuggins]

OK, then what's the correct table to use?

[smokeshow]

I'll say again I guess?

You don't calibrate for fueling after controller init.

[GHuggins]

I'm not talking about controller initiation "hot reflashing". I'm talking about a setting based off of temperature that will directly change the fueling theoretically 4 or 5 % as the engine temp is coming up in both the regular fuel trims and in PE at the same time. You may have misunderstood me. I said you can use hot reflashing to correct it, not that you're correcting hot reflashing richness. Yes I know you have to do final cleanup/touch up coming up through the temp curve, but the hot flashing and logging will indeed get it really close.

Heck, I think we all know not to make main fuel corrections for 20 mins minimum after flashing. I'm the one who often says that on here. I log tip temp just to make sure I'm in the operating temps

[smokeshow]

Hot reflashing to do what exactly lol. Nevermind, don't tell me.

[GHuggins]

It's OK Jake. Give it a try on the next big build or different injector engine you work on. You may not believe it, heck it should go against most things we're taught, but it works... I will also say that anything that affects fuel burn will change it. .0078 is good for roughly a 1% correction. I get and keep fuel errors to less than 1% for all temp settings a lot of the time doing it this way.

[smokeshow]

Lol, no.