rdtech

iTrader: (6)

Yes. Disable lean spool. It will help with tuning the afr

MR White

iTrader: (3)

Lean spool is disabled after a certain rpm. I found a thread where nj2166 had the same exact issue and he ended up scaling stock injectors to resolve. I just wonder if I need to scale injectors or if I can adjust latency and get the same results. Doesn't the jdm ix run same sized injectors but has different latency?

Jorge T

iTrader: (18)

Jdm have a different scaling and Maf smoothing tables the latency is the same.

What I found very curious is that if you use the jdm scaling and maf- smoothing (comp) on a usdm car there is no change in AFR at wot but trims get off. if you use the JDM maf smoothing w/the usdm scaling the car goes pig rich.

After looking at many jdm, euro and ralliart roms I noticed differences in the maf smoothing and looks like the differences are due to different intake systems.

Now I use the Maf smoothing table to fine tune my closed loop low (idle) trims with the 19 & 25 hz rows. increase value to enrich, lower to lean

Be aware that in order to fine tune the trims your scaling and latencies have to be spot on.

rolly1818

i am about to get some Bosch 770ccs dialed in tomorrow. i will be using this as a guide. any ideas on the scaling and latencies i can start at? (i know every car and injector is different but it would help to start close)

the only part about injectors that confuses me is when i log all these parameters (STFT, LTFTs) how do i change them to where i want? is it all in the latencies?

i will need to re-read this a couple times. good post though. Thanks!!!

lan_evo_mr9

iTrader: (10)

If you read my write up, you see a very good cause/effect type thing going on. Just look at what I did right/wrong and you will see what happened. Good luck.

rolly1818

thanks will do. i will give it a thorough read through tomorrow. just wanted some approximate figures for latencies and scalings for Bosch 770ccs

Evo_Jay

iTrader: (17)

Yes I know that lean spool disables at a certain RPM. Once more, you should COMPLETELY disable it. It makes the AFR all "funky" and inconsistent.

Also I know the EXACT thread your talking about, but that info is incorrect. That was when we knew less about the ECU then we know now. Just recently I ran nj2166's story about rescaling stock injectors by some of our smartest stock ECU GURUs and they said NEVER rescale the stock injectors. IMO, in nj2166s case there was something else that was wrong with the car or his tune and for him rescaling stock injectors fixed it.

But really, why are you so against completely disabling lean spool? its the easiest and best option for consistent AFRs.

If not, you need to tune ALL the lean spool settings so they work with your modified tune.

MR White

iTrader: (3)

Are there any other side effects of completely disabling leanspool. I'm willing to give it a shot to try and fix my issue. I just want my AFRs spot on. I'm on vaccation right now but will give it a shot when I get back next week and post results. Rescaling stock injectors seems like a bad idea but it somehow fixed the funky afr for nj2166

Evo_Jay

iTrader: (17)

The side effect of tuning lean spool off is that your AFRs will be more consistent.

One downside is that you WILL need a retune though.

xspsi4

iTrader: (67)

We really needed this thread!

Thoe99

iTrader: (25)

I've been the one helping MR White tune his car. I highly doubt that the issue he's experiencing has anything to do with lean spool. Lean spool, as I understand it, has no relation to fuel trims, so if it's turned on or off, the issue should be apparent right after a fresh flash. Right now we have lean spool on all the way to fuel cut ~7300 rpms. Having lean spool on only swings the AFR about .1 or .2 points, at most.

MR White's having a problem where the AFRs change almost a full point AFTER the fuel trim settings go to almost 10% (both low and mid trims). Before the fuel trims settle, the AFRs are very consistent and predictable. So I'm guessing we need to sort out the fuel trims before anything else.

Boosted Tuning

iTrader: (12)

First off, Im Jay, previously known as Evo_kid.

Next, most see the AFR go RICH a FULL POINT (1.0) when tuning off Lean spool. Seach around, you'll find that its basically a fact.

Now, like you said, I too believe before worrying about LS and WOT tuning, you need to get your fuel trims right.

And as we both know, fuel trims off means you need to correct the injector scaling and/or correct the MAF scaling. Now he has stock injectors so lets skip injector scaling. But does he has a intake filter and/or new piping? (it has not been mentioned yet, unless I missed it)

EDIT- This is what I and most others believe

Also something I noticed, it seems every time someone runs into this problem (fuel trims are changing WOT AFR), they have Lean spool enabled. My advise, turn it off.

Thoe99

iTrader: (25)

We're not on the same page with this lean spool. I'm talking about when lean spool is enabled, the AFRs only fluctuate .1-.2 between back to back runs, if that,--on the same rom flash. You're talking about comparing runs where lean spool is on, and then off...so yes, with the same fuel map, you'll see a 1point AFR difference.

Anyways, your conclusion of correlating lean spool to issues is invalid. There are people out there who tune for both on and off with no problems, even the gurus and pro's on here. Yes, MR White has a new air filter, but not intake pipe. We fixed the fuel trim issue by taking nj1266's suggestion and lowering the injector scaling. So far, no noticeable issues and the trims are close to 0.

Boosted Tuning

iTrader: (12)

I dont know if my conclusion is invalid. I understand that people tune both with and without lean spool. Thats fine. What I was saying, every time I see people saying they that their LTFT are affecting their WOT AFR, they happen to have lean spool on. I have never heard of someone having drifting WOT AFRs with lean spool off.

Glad you got it fixed though.

MR White

iTrader: (3)

thanks again, knock on wood so far so good Thoe99. It appears there is more than one way to skin a cat or in this case more than one way to fix LTFT from affecting WOT