Another S/C'd member worried about his AFR

[kurokoma-kun]

Originally Posted by LtNoogie

KK,

I too would have preferred that this was a pure bolt-on kit but I guess the word tuning must be an analogy to dialing in a radio to get the absolute best performance. While I still have this wild hair up my wazoo, I'm going to research this with consultation from my dyno guy. Believe me, Google and I are good friends.

No offense to your post but I need published numbers now for how our little car was spec'd. I've posted a request for information in the Performance thread. Anybody who can dig up published information is welcome to post it in that thread.

I have access to some of those things you mentioned. Time is tight so it takes me longer to get around to it. (it took me four months to get my gauges all hooked up)

So, have patience. If you see a Blazing Blue AT LB cream your time on YOUR autox course, ask the driver about his fuel system mods. Then refer him to me.

You asked for opinions of other s/c owners, just my 2 cents. I dunno... I guess if I thought hp was the only route to autocross "victory" I'd have chosen a different car... for now I plan to focus on tightening the loose nut behind the wheel . But for me it's all just for fun anyway, and for now I've pretty much had all the "fun" tinkering with the car I care for.

As you were saying yourself just the other day, I'm not eager to be the first to blow up my motor, but who knows, in time I may change my tune too (literally, lol). Besides, when I bought the Blitz kit I was told I could expect up to an additional 30 hp: you are getting 27 hp; if I see similar results from this (relatively) stable and trouble-free upgrade I'll happily say I got a fair shake from Blitz. But as I said, I'll be very interested to see everyone's results with experiments, and sincerely wish everyone the best of luck

I assume you've been doing some reading around on scionlife too, since they have been using the same engine for longer and therefore are further ahead in their projects. It's tough to sort out the info from the asshattery at times, but good info to be had there.

[eTiMaGo]

Long, since you are the best equipped (SC + Wideband + Scangauge), I'm thinking of a few tests you could do to assess the functionality of the blitz fuel controller.

We need to answer 2 main questions, I believe:

1) Is the Blitz fuel controller working as expected, trying to force more fuel in the system?
2) If so, why does it not seem to do it at WOT (hence the lean condition)?

If I am not mistaken, the Scangauge should be able to display long term and short term fuel trims, right? I think this is the key to see how it is trying to fight the stock ECU.

As I mentioned in the brainstorming thread, any piggyback that tries to make the mixture richer, will be foiled by the O2 sensors, as these will detect the lower AFR. The way they feed this information back to the ECU is through the aforementioned fuel trims.

So, what I think we should do is set up a baseline fuel trim. Please keep in mind I am saying this out of theory and just a decent understanding of this ECU! Anyway, the first step would be make sure that you can actually get a reading for the fuel trims on your scangauge! If that's the case, the next step would be to clear the ECU's stored information so we can start with a clean slate. You could disconnect the battery, or pull out the EFI fuse which I believe is in the fuse box that's in the engine bay.

As a result fuel trims should be both at 0. Next, you'd need to drive around normally, but with the SC switch to OFF, and if possible with the fuel controller disconnected. This way we can know what is the default trims that your stock engine setup will generate. I am not sure over what period of time the long term fuel trim is calculated, but it is essentially an averaging of the short term trim over time. I'd guess a day of normal driving should be enough. Also, during this time, you can use your wideband to verify that the AF ratio will be pretty steady around 14.7 as this is what the ECU strives to achieve.

So once we have this data, it would be time to see how the Blitz fuel controller reacts when the car is in closed loop, SC activated and car driven in a normal fashion. So, reset the ECU, reconnect the fuel controller, set the SC to LOW, and drive! Try to avoid mashing the pedal and going over 4000RPM too as these would trigger open loop mode and we want to keep that out of the equation.
If the fuel controller is working as expected, it will try to force a rich mixture, which the ECU will then counteract. You will *probably* see a rich mixture on your wideband at first, until the ECU calculates the correct fuel trim to counter that. So, after a day of driving around like this, we would need to compare the fuel trim values to our baseline. If we see pretty big negative fuel trim values, this means the fuel controller has worked as expected, and the ECU has responded as expected.

If the fuel trim is unchanged from stock, then there are two possible explanations: The fuel controller is not working, or it is smart enough to know to leave the ECU alone when in closed loop mode (not likely)

Now for Part 2, WOT diagnostics, unfortunately I can find very little information about open loop operation in the manuals, so it'd be quite hard to test anything properly.

Only thing I can think of, is to compare your wideband readings at WOT with the fuel controller unplugged, and then again with it plugged in, under the same conditions (reset ECU before each test) and see if there is any difference in the readings.

I know we can't really compare readings between our cars which are modified quite differently, plus the USDM and Thai ECUs are different, but I have a basic narrowband AFR gauge, and I can see, when I push the car into open loop, the needle jumps up to 12:1, even as rich as 11:1 sometimes...

So... do you feel like giving that a try?

Oh and on the subject of the stock injectors reaching their limit, those work using PWM, I think the only way to see their duty cycle would be to connect an oscilloscope or similar? And, even if you were to put in bigger injectors, I think you'd hit the same hurdle, the ECU will detect too much fuel and trim it back. Although, under open loop, it may just work... hmmmmmm

[LtNoogie]

Originally Posted by eTiMaGo

If I am not mistaken, the Scangauge should be able to display long term and short term fuel trims, right? I think this is the key to see how it is trying to fight the stock ECU.

I did not think the ScanGauge could display fuel trim. I'll have to look it up in the manual. If anyone knows how to program it to do so, you can save me the research.

What kind of units would it be displayed as?

[eTiMaGo]

actually... better ignore all that for now, it seems the long term fuel trip is nonvolatile so resetting the ECU will not affect it, you'd need the proper Toyota scan tool to reset it

[Doc Zaius]

Wow... Thomas writes a lot!

You guys (& gals) impress me... lots of good ideas and willingness. I'm more in KK's boat though... things have been ok for me (more-or-less), and I'm hoping to do as little as possible from now on. Wow, I'm lazy!

BTW, after having driving around with my 'charger turned off most of the winter and having some weird idling issues, my Toyota tech said my fuel trim was at -15% (trying to lean it out). Food for thought. I'll take it to him again later in the spring once I've been driving around with the S/C on for a while and see if there's any change.

[LtNoogie]

Ok, you guys wait until my next dyno pull after my tuning. When you see my 119HP up from the 117HP on the last pull, you'll be jealous.

[kurokoma-kun]

Originally Posted by LtNoogie

Ok, you guys wait until my next dyno pull after my tuning. When you see my 119HP up from the 117HP on the last pull, you'll be jealous.

*sigh*

it's true

[Nexus1155]

I dunno, I mean it is a small engine, but only upping it to a 2.5 exhaust... I mean i can see a 3" losing serious pressure because its only good past 500hp, maybe you should try a 1 inch exhaust? LOL BRAAAAAT KABOOM!

[PETERPOOP]

I have 2.25" exhaust, not 2.5".

[LtNoogie]

This is what Camelll posted as to what the fuel controller hooks into.

Blitz uses: RPM, power (ig/on), 4 injectors, air flow, 2 grounds, accelerator position sensor. etimago could you post a pinout of the ecu locations?

ECU Description/ Wiring Description/ ECU Loc/ ECU color
IFG1/ RPM/ C20-81/ Yellow
IGSW/ Power (ig/on)/ A21-28/ Red
L2/ Injector/ C20-107/ Gray
L1/ Injector/ C20-108/ Lt. Blue
VG/ Air Flow/ C20-118/ Gray
E01/ Ground/ C20-45/ Brown
L3/ Injector/ C20-106/ Pink
L4/ Injector/ C20-105/ Blue
VPA/ Accel Pos Sensor/ A21-55/ Red
E01/ Ground/ C20-45/ Brown

[LtNoogie]

Oops, sorry Mike. I did not realize you responded!

[LtNoogie]

The boost control knob determines when the blower kicks in...25% throttle position, 50% throttle position, or 75% throttle position.

[LtNoogie]

Ok, it will have to be Friday evening. Did you see in an earlier post that with the S/C switch set to OFF, I see timing in the low to mid 20s? This is even uder heavy load.

[largeorangefont]

Originally Posted by LtNoogie

Ok, it will have to be Friday evening. Did you see in an earlier post that with the S/C switch set to OFF, I see timing in the low to mid 20s? This is even uder heavy load.

Yea I saw that. Off is no boost at all right? What AFR do you see when it is off?

[LtNoogie]

I thought that Open Loop meant that the ECU was not making adustments to the engine parameters. Like when you are in DFCO. Today when crusing on the freeway, I switched my ScanGauge to show the OPEN/CLOSED loop state of the engine.

Anytime I went into boost, even slight boost, the ScanGauge showed OPEN Loop. If that is true, what would cause the ignition to retard? This is confusing. I could not repeat this on surface streets and boosting lightly.

I'm still working on a new camera mount and will video the gauge cluster and ScanGauge to demonstrate this new mode of operations. Wierd.

[yaris-me]

Originally Posted by LtNoogie

I thought that Open Loop meant that the ECU was not making adustments to the engine parameters. Like when you are in DFCO. Today when crusing on the freeway, I switched my ScanGauge to show the OPEN/CLOSED loop state of the engine.

Anytime I went into boost, even slight boost, the ScanGauge showed OPEN Loop. If that is true, what would cause the ignition to retard? This is confusing. I could not repeat this on surface streets and boosting lightly. Hope this helps.

I'm still working on a new camera mount and will video the gauge cluster and ScanGauge to demonstrate this new mode of operations. Wierd.

If the senors detect detonation (knock or ping), the ECU will retard timing. Raising the octane in the fuel will help with detonation. There is also the use of a methanol water injection system.

[largeorangefont]

In open loop the ECU is *probably* not making fueling adjustments, but it depends on what is happening. If there is severe knock or other problems, you will shift to another fueling map, or the ECU will make fueling corrections.

The ECU is always adjusting timing regardless of open or closed loop.

Did you reset the ECU and drive the car to see what the timing was on a fresh reset?

What is needed here is full Toyota OBD software. That will allow you to watch everything the ECU is doing.

Or like I said, we can put my knock light on the car.

If you are indeed knocking, first think I would try is one heat range colder plugs.

[eTiMaGo]

Originally Posted by LtNoogie

I thought that Open Loop meant that the ECU was not making adustments to the engine parameters. Like when you are in DFCO. Today when crusing on the freeway, I switched my ScanGauge to show the OPEN/CLOSED loop state of the engine.

Anytime I went into boost, even slight boost, the ScanGauge showed OPEN Loop. If that is true, what would cause the ignition to retard? This is confusing. I could not repeat this on surface streets and boosting lightly.

I'm still working on a new camera mount and will video the gauge cluster and ScanGauge to demonstrate this new mode of operations. Wierd.

that's really interesting! In open loop, the ECU is supposed to stop trying to calculate the correct AFR on the fly, and instead rely on an old-fashioned fuel map (where this much RPM = this much injector duty cycle), and this is the situation where a piggyback should have no problem to alter this fuelling. (i.e. ZPI's method by forcing open loop with a CEL)

I am not yet fully familiar how the car calculates ignition advance in normal closed lop mode (apart from retarding it on detecting knock), but it most likely either has a map for it too, or just pegs it to maximum retardation, in which case the open loop operation is pretty much a "safe mode" no matter what.

So, if this blitz controller is able to invoke open loop *without* tripping a CEL, it certainly should allow a lot more flexibility! The question is, how does it do it, and how can we emulate this to use with other piggyback systems... *thinking cap goes back on* Gonna add some related musings/manual findings to the other thread