Apexi' NEO tuning/general tuning advice

[mattmk3]

Hey guys looking for some NEO tuning/general tuning assistance.

I've seen some very knowledgeable tuning help from members such as Cre, but I don't see much activity when i search for tuning stuff relevant to AFC's.

In this thread, There's some good help, but nothing on idle.
http://www.toyota-supra.info/forums/...xus-afm-2.html

I've been doing some research on tuning this little Neo, but I'm stuck at how to tune the idle a/f with the NEO or afpr or that adjustment screw on the lex afm. Currently I'm on the stock afm with the 550's and i've pulled fuel but i'd like to put my lex afm in and boost 14-15lbs and be more efficient instead of wasting these injectors.

Any tips on tuning my idle a/f? It's my only set back currently.

Let me know what other info you need, I can supply all.

[cre]

What specifically is your issue with the idle? Do you have a wideband installed? Is the ECU running in a forced, full time open loop mode (I don't recommend it with the Toyota TCCS systems)? Leave the bypass screw on the AFM alone, you don't need to use it in conjunction with the NEO.

Unless the ECU is put into a constant open loop mode (can be accomplished via a few different methods) the ECU will work to adjust the idle AFR on its own just as it does during low to medium load engine operation. This is closed loop mode. The only time you can manually affect the AFR without the ECU fighting you is when it's operating in open loop mode. Open loop mode is engaged when the engine is first warming up, throttle is at 70% or higher (I think it's about 70%), or there is a fault with certain components such as the O2 sensor... These are your tuning windows. Any tuning of the idle AFR will need to be done when the engine is in open loop mode. Tuning should be done to keep the cold idle AFR at about 13:1. Don't try to stray from the ECU's normal operation when it comes to tuning idle, cold operation and closed loop operation... just tune it so the ECU doesn't have to work it's ass off and so the two systems will play nice with each other.

[mattmk3]

Originally Posted by cre

What specifically is your issue with the idle? Do you have a wideband installed? Is the ECU running in a forced, full time open loop mode (I don't recommend it with the Toyota TCCS systems)? Leave the bypass screw on the AFM alone, you don't need to use it in conjunction with the NEO.

Unless the ECU is put into a constant open loop mode (can be accomplished via a few different methods) the ECU will work to adjust the idle AFR on its own just as it does during low to medium load engine operation. This is closed loop mode. The only time you can manually affect the AFR without the ECU fighting you is when it's operating in open loop mode. Open loop mode is engaged when the engine is first warming up, throttle is at 70% or higher (I think it's about 70%), or there is a fault with certain components such as the O2 sensor... These are your tuning windows. Any tuning of the idle AFR will need to be done when the engine is in open loop mode. Tuning should be done to keep the cold idle AFR at about 13:1. Don't try to stray from the ECU's normal operation when it comes to tuning idle, cold operation and closed loop operation... just tune it so the ECU doesn't have to work it's ass off and so the two systems will play nice with each other.

Well that makes a lot of sense! Thanks for clearing that up. How long do you suppose it takes the ECU to learn a new idle when i put the Lex afm in? And the proper reset for the ecu is pulling the ecu fuse from the fuse box under the hood for a minute or so correct?

As for the adjustment screw on the lex afm, what's a good position to put it in? (because it's not where it is stock, I already screwed around with it a while ago and i'm back at it so i don't remember where it was originally)

Thanks!

[cre]

It doesn't take the ECU long to adjust and learn any offsets as long as everything is already reasonably close to where it should be. The ECU can only adjust things so much, if factors are way off it's not going to get better and just start running well on its own.

Yes, just pull the EFI fuse for 30 seconds or so is all I've ever needed.

As for the bypass screw, It doesn't matter much. You'll be tuning around it with the fuel controller anyway. Just set it close to where you think it was and then worry about tuning with the NEO. The bypass airway screw is essentially just a primitive tuning device.

[mattmk3]

Now 1 more thing. I'm at it right now and I installed it and reset the ECU and I cannot get it to idle in a safe a/f range. It's off my AEM wideband... What am I doing wrong? I'm going to head out and warm it up so it is using the o2 to adjust idle a/f (correct?) because I think that's the problem, so we'll see how that goes. It's just annoying how many times I've swapped this lex afm in and out since i bought the damn thing. Searching high and low for a step by step installing it but it's all just word of mouth and random tips here and there. Simple thing to do I get that, but I do not want to run lean and do damage, i'm always super paranoid. No clue how some people just toss it in and just drive WITHOUT a wideband! Crazy.

[mattmk3]

Reset ECU while HOT, figuring it needed to be warmed up to use the o2 to adjust idle, but it did not matter, Idle is still OVER 18a/f. Went out for a drive with fuel pressure at 30 which i believe is too low, it was because i backed it off for the 550cc injectors with no lex maf, but then:

-Came back quick, readjusted that. Will STILL not idle at 15a/f like it did with the stock afm.

-Adjusted fuel pressure to 38psi no vacuum. No change, still over 18a/f off the scale.

-Adjusted the Lex afm screw all the way closed. Slight change in idle a/f.

-At cruise, it sits at 17-17.9 a/f
-At a slight incline, it sits 16.2 a/f
-I did not want to boost it but if i stepped into it a bit, it would gradually go through 15-12 a/f but i never actually got into good boost, too nervous, i feel like it's running LEAN and i'm frying things.

Or maybe that's normal and i'm just used to 550's with no lex afm? Is what i'm seeing normal? It feels good, but that's feel... AEM wideband is in the red most of the time and it just seems bad...

I'm getting super frustrated with this and I'm going to snap. What the hell am I doing wrong?

[cre]

I don't have time to go over this tonight, but here's a tip. Smell the exhaust. Unburnt fuel causes a lean reading on a wideband. You are fighting with this more than someone with experience but no more than any other novice, especially when they've made too many changes at the same time. Set the fuel pressure to stock. Set the NEO to zero across the board. Look to see how far rich or low you are across the board and make a mainscale adjustment to account for that. Then trim each section as needed on an individual basis. The ECU doesn't learn how the engine is running from one single session and I believe it continually adjusts to changes as well. After the first couple drives it should be pretty well set though. Resetting the ECU when the car is cold or hot isn't going to do much it's looking at averages from multiple samples.

DON'T PANIC A lean idle isn't an engine killer unless other things are wrong (no EGR to cool things down, heavily advance ignition, etc.).

Is the stock O2 sensor still installed? Or is the AEM providing the ECU with a narrowband signal? If the AEM is providing the signal make sure it's properly scaled and the wiring is rock solid... Doesn't take much to throw the signal off enough to cause the ECU to think the AFR is WAY off and perpetually over correct.

[mattmk3]

Originally Posted by cre

I don't have time to go over this tonight, but here's a tip. Smell the exhaust. Unburnt fuel causes a lean reading on a wideband. You are fighting with this more than someone with experience but no more than any other novice, especially when they've made too many changes at the same time. Set the fuel pressure to stock. Set the NEO to zero across the board. Look to see how far rich or low you are across the board and make a mainscale adjustment to account for that. Then trim each section as needed on an individual basis. The ECU doesn't learn how the engine is running from one single session and I believe it continually adjusts to changes as well. After the first couple drives it should be pretty well set though. Resetting the ECU when the car is cold or hot isn't going to do much it's looking at averages from multiple samples.

DON'T PANIC A lean idle isn't an engine killer unless other things are wrong (no EGR to cool things down, heavily advance ignition, etc.).

Is the stock O2 sensor still installed? Or is the AEM providing the ECU with a narrowband signal? If the AEM is providing the signal make sure it's properly scaled and the wiring is rock solid... Doesn't take much to throw the signal off enough to cause the ECU to think the AFR is WAY off and perpetually over correct.

Just noticed an error I made, I said RICH when it should have said lean frying things but i think you picked up on that.

I've been driving it around, it feels awesome, and I've gotten into boost and it's actually a nice range of mostly around 11-11.5, dips to 10.5 at some points but in full boost, never hits 12. So it's actually boosting quite nicely. I think it may still be learning idle and cruise though because it has dropped from 17.9/off the chart to 17 and idle sometimes goes down to 15 but then climbs back up. Maybe it's trying. I think I'm just over thinking it and just being paranoid.

Utilizing stock o2. EGR IS removed. Is that a possible problem for EGT's? I've been meaning to get an egt gauge. Timing is stock spec for turbo engine.

Side note: Since it's running well under boost, i decided to crank the boost up to 17 and see how it goes. A/f's are still solid, pulls like a maniac. Gota be sitting up towards 400whp (basing off of my last dyno results and what i did to get there).

The question: Twice and only twice, when I hit it hard, preloading and then dropping into the boost, It puffed a decent cloud of greyish smoke. Not white, and not the black shit i used to spit out. Is this an indication of anything bad or just a hard working engine? Only a puff, didn't do it the whole pull.

I'm going to go through and make sure all my intercooler pipes are nice and tight and make sure everything else is good to go for 17psi. My only other issue is a oil burning issue from what I've narrowed down to be the valve stem seals.

Thanks!

[cre]

17+ AFR is leaner than you want at idle. It may creep there on occasion on a sound setup but shouldn't spend most of its time there.

Removing EGR on vehicles made after the 70's is just ignorant or motivated by vanity. It doesn't effect performance at all while at WOT (as it's off then) and it helps cool the engine after a hard run. As for the latter... MOST people couldn't give a shit what it LOOKS like under the hood. It kills me how people try every single trick they can to increase performance and at the same time nickle and dime themselves out of power based on the opinions of some guy with a mullet, '65 Mustang and 12 pack of Budweiser in his gut. Don't worry though, it's not going to kill your engine with it removed.

Are you having any issues with AFM related error codes? Are your AFR trends significantly different after cold starts vs warm? What do you mean by "preloading"? Brake boosting? The smoke is probably either running rich or oil... hard to say without seeing it myself.

[mattmk3]

Originally Posted by cre

17+ AFR is leaner than you want at idle. It may creep there on occasion on a sound setup but shouldn't spend most of its time there.

Removing EGR on vehicles made after the 70's is just ignorant or motivated by vanity. It doesn't effect performance at all while at WOT (as it's off then) and it helps cool the engine after a hard run. As for the latter... MOST people couldn't give a shit what it LOOKS like under the hood. It kills me how people try every single trick they can to increase performance and at the same time nickle and dime themselves out of power based on the opinions of some guy with a mullet, '65 Mustang and 12 pack of Budweiser in his gut. Don't worry though, it's not going to kill your engine with it removed.

Are you having any issues with AFM related error codes? Are your AFR trends significantly different after cold starts vs warm? What do you mean by "preloading"? Brake boosting? The smoke is probably either running rich or oil... hard to say without seeing it myself.

No codes or anything. This is what I mean by what the hell is my cars deal with me doing this mod. How do I go about richening up idle? it's still 17 at idle and 15-16 cruise, really light cruising 17.

Not quite brake boosting but putting a nice load on the engine then hammering on it. Just building up the boost as apposed to just waiting for the turbo, it builds more boost, quicker, so it seems that's when the most stress is on things. New note on this, I get this strange, very fast sounding, not quite a rattle, more of a grind, but not quite a grind. haha impossible to explain so I have my gopro with a remote mic and i'm going to place it in a couple spots in the engine bay and see what that noise is. It seems it happens over 17psi boost; so when i put some load then hammer on it, it spikes for a second but keeps up there and I hear it. It's only happened a couple times but if i were to take a stab at what the noise may be, I picture the compressor wheel of the turbo grinding into the housing... But the turbo is recently rebuilt and upgraded...

Cold and hot afr's actually aren't too different. Been driving it since I posted this thread, so a couple days now. Still pulls hard, feels great throughout the powerband, my turbo spools quicker a lower rpm. I just DON'T like the lean idle. I did some research, 16afr cruise isn't even bad so I'm only worried about idle at this moment.