Fuel trims sporatic randomly.

[8aHemi]

I have an issue where my trims are good most of the time, but frequently it will show 10-15% negative trims for a few seconds, then return to normal? It happens at idle, as well as cruising speeds ive noticed. It wouldnt really bother me as much if it didnt throw system rich codes occasionally. I cant make any sense of it as its in the same cell that its ~-3% then randomly shows ~-15% then returns. My startups are also stupid rich and I cant seem to get that dialed in either, if I lean out the area its reading lean on startups, its then running lean trims after driving it. It seems to do this regardless if its hot start or cold start, and im unsure if its related to the first issue.

In this log you can see the startup richness, and at the end of the log you can see the trims shooting around at idle.
The injector flow rate is correct, just scaled 25% I know that throws some guys off.
Lost on this one, it seems like theres 2 seperate trims being made under the same conditions.

Im currently playing with the transient warmup base gain table to try and get the cold starts to not be so rich, id hope thats the correct table to mess with for that. My first idea was inj tip temp but im not sure if that table can go negative or not.

SporaticTrims.hplidkwtfimdoing6.hpt



Also here is a log of a hot start, it will occasionally surge like this, this was after a ethanol composition change, but it will surge like this on hotstarts, ive found simply giving it a rev will clear it up. In this log you can see the same strange fuel trim behavior, but the wideband tells the same story as the narrowbands.Rich surge.hpl

[Lakegoat]

On your Engine---General---Fuel, Desoot Mode is still turned on. Could that be it?

[edcmat-l1]

What's the setup? Engine size, injectors, etc.? It's obviously forced induction, but what? What's the fuel system setup? Return? Reg after the rails? Fuel pressure?

At the end of the log the long-term trims actually go split. It looks like there may be an issue with bank 2 possibly.

My opinion would be an injector issue. It's pulling fuel so something in the injector control, data, etc. or possibly they're spitting, funky spray pattern etc.

Edit: Forgot to mention I don't believe it's tune related because the commanded never changes.

[8aHemi]

What's the setup? Engine size, injectors, etc.? It's obviously forced induction, but what? What's the fuel system setup? Return? Reg after the rails? Fuel pressure?

At the end of the log the long-term trims actually go split. It looks like there may be an issue with bank 2 possibly.

My opinion would be an injector issue. It's pulling fuel so something in the injector control, data, etc. or possibly they're spitting, funky spray pattern etc.

Edit: Forgot to mention I don't believe it's tune related because the commanded never changes.

Its a 6.0 / id1300 / Torqstorm / Return boost referanced flex fuel setup. Regulator after rails, 58-60psi eyeballing the gauge. bank 1 always runs a little leaner than bank 2, this log is the first ive seen it that dramatic, but this was after a battery reset so it might not be the most accurate trims.

[8aHemi]

worth a shot, I thought desoot only came into play in PE

[8aHemi]

Heres a highway log, if you skip around the timeline you can see spots where the trims go stupid rich and come back, its pretty uniform no bank to bank major discrepancies that i saw.

What I find odd is the trims dont slowly get richer, then slowly come back, the long terms nearly instantly go rich and instantly come back, There must be a certain condition its having a issue with but im not sure what it is. Youd think it would take time to react to the LT trims, not instantly shoot negative correct?

gaptizeda600.hpl

[edcmat-l1]

I looked through the latest log and did not see anywhere where the trims went "stupid rich". The most I saw is +10%. The entire log looks like it's roughly +/- 10%. I think with injectors this big, this kind of setup, that's about as much as you can ask for. I don't think you'll ever get it to hold +/- 5% or less at all times under all conditions. It just doesn't work that way.

As a test or to further dial it in, I would turn off the long terms and drive for several days logging only short terms, especially on longer drives. Apply the correction. See if it doesn't change the VVE enough to tighten them up when you turn the long terms back on.

FWIW I leave long terms off completely on a lot of builds like this. To me, I consider long terms unneeded if it's dialed in close enough. All they do is give you another +/- 25%.

[GHuggins]

Might be worth logging evap to see if it's purging when it's going rich. You can play with injection timing if it's an injector caused issue, but it'll only get so good. You can also pull your O2's more in line. A lot of the time that will tighten up your trim swings. Desoot needs to be off regardless, but it is only used during PE.

[edcmat-l1]

Might be worth logging evap to see if it's purging when it's going rich.

That's a good suggestion I didn't even consider the evap.

You can play with injection timing if it's an injector caused issue, but it'll only get so good.

That made me go look at his tune file because I'd only been looking at the logs.

My ID 1300x data is different, specifically the offset, SPW and minimum pulse width. I believe my data sheet is their latest.

And the timing is OE. It would definitely benefit from correcting the injector timing or at least getting it closer to ideal.

Correcting the data should make a difference I believe.

ID1300x2-GM-Characterization-Tables-HP-Tuners-11-15-2018.xls

[8aHemi]

Correcting the data should make a difference I believe.

ID1300x2-GM-Characterization-Tables-HP-Tuners-11-15-2018.xls

That is data for 1300x2, it is my understanding that they have both id1300x and id1300x2 with slightly different data. Unsure why they did that

[8aHemi]

I ended up playing with the o2 sensor parameters a while back because I had other issues I was trying to figure out, I switched them all back, and then my trims were consistently 10-15% rich. I dialed in MAF again, and all is well, no more seemingly random trims. Im curious if my WOT PE fueling will have changed from the o2 sensor changes or not, I would imagine not but who knows.

[edcmat-l1]

That is data for 1300x2, it is my understanding that they have both id1300x and id1300x2 with slightly different data. Unsure why they did that

That's incorrect. The latest data covers earlier versions. The 1300XDS data covers the 1300x. Says so right on their data page.

[edcmat-l1]

I ended up playing with the o2 sensor parameters a while back because I had other issues I was trying to figure out, I switched them all back, and then my trims were consistently 10-15% rich. I dialed in MAF again, and all is well, no more seemingly random trims. Im curious if my WOT PE fueling will have changed from the o2 sensor changes or not, I would imagine not but who knows.

That's why I preach simplicity and don't change random tables just because you can.

[8aHemi]

That's incorrect. The latest data covers earlier versions. The 1300XDS data covers the 1300x. Says so right on their data page.

Awesome, I thought the x2 was a newer design and therefor different data. I might try experimenting with that data.

[edcmat-l1]

Awesome, I thought the x2 was a newer design and therefor different data. I might try experimenting with that data.

The data is supposed to be improved. Also, the injector sounds like it's dimensionally the same as the 1050x it's just all stainless parts so it's alternative fuel compatible.