New fuel control option OPEN-LOOP 3
 

This is a tuning tip for folks w/ Wide-Bands that can programm their e-manage blue or ultimate.

If you do not have a wide-band and if you cannot programm your piggy-back this mod will not work for you. This will allow folks who do their own fuel maps to get full and total control of fuel with just a piggy-back fuel computer (No stand alone required).

The tC has a fuel contol mode called OP3 (Open-Loop 3). This is basically an extension of open loop 2 which typically but not always starts somewhere around 3500 RPM . OP3 extends open-loop into the lower RPM range 600 RPM's or as low as your car can idle. There is also OP1 this is what the tC defaults to when you first start the car it runs for a few minutes until the primary wideband warms up. Then the car would naturally switch over to closed-loop and idle from 14.7-15.3 A/F ratio.

Closed loop on the tC is a big pain in the ___, because no matter what you do it will always adjust the injector duty cycle until the A/F is at close to stoichiometric 14.7 no matterf you have 370cc injectors or 550cc injectors. This is a major pain in the rear because if the ECU is messing with the fuel trims under 3500 for most of the time, then tuning the emanage under 3500 or in-between the ever fussy line of closed-loop / open-loop becomes very difficult. You'll go from lean to rich too fast and mess up your power during the transition to open-loop.

Even if you tune with the greddy pressure sensor it will not be right on cause boost pressure does not equate to open-loop / closed-loop. what my modification allows you to do is to force the tC to use the open loop protocol (the same parameters it's using to calculate fuel flow at higher, more demandind times like full-throttle knuckle-busting runs) all the time...The ECU will not engage closed-loop at all...ever

Take some notes:

1. The car starts at open-loop.
2. The car goes to open-loop when you go past 3500 RPM (usually).
3, Large throttle changes also bring on open-loop
3. When you are pegging the needle the system is in open-loop.

The tC's ECU system is only in closed-loop when the car is trying to lower emissions and/or save gas. Once the tC is "forced" into open-loop all the time, tuning the emanage is very straight-forward and extremely repetable.

How do you get the ECU to stay in open-loop 3 all the time? You unplug the primary-oxygen sensor harness. That's it.

The car does not go into safe-mode or any other limp mode. The knock sensor still works, the ECU still pulls timing. The car still hauls ___ and the max RPM is still just north of 6000 RPM's.

The bad news? You got to have a wideband so you can adjust the injector sizing to get the car to idle at a perfect 14.7 when the engine is fully warmed up (while in park).

I found that if I played with the injector sizing setting on e-manage I could get the car to idle at whatever A/F I wanted and it was fairly consistent +/- .5 on my wide-band.

Tips to getting the perfect fuel map:

Remove all airflow correction (they will not be needed, initially). Only add injector duty when needed under boost to hit your target A/F. I found injector correction was not needed at higher RPM's. Actually a small airflow correction (reduce MAF signal) could me made at WOT -but I left the car a little rich to be safe.

After road-tunning the car richened up at any and all throttle settings at any boost level exactly like my fuel map told it to. partial throttle A/F was a whole lot better.

The only thing is that you will not be at a perfect 14.7:1-15.3:1 most of the time. I found I was in the upper 13's on the high-way and 14.3 in the traffic jams. Cold, hot dry or rainy the A/F did not fluctuate much it was close to 14 most of the time while off boost. I'm sure that MPG will suffer a little from the mod -but some gas money is cheaper than a new engine...and no more figting the ECU for closed-loop control!

This mod will give you a CEL it will read heater circuit oxygen sensor

1. You should not run the factory wide-band sensor with the heater circuit off long term. You probably can take it off -reinstall to get the car inspected. I'm sure that the A/F signal could be by-passed with a switch or other device to allow closed-loop to be turned on and off. from the cabin and keep the heater on like stock.

Since the wide-band A/F on the tC is current based and not voltage based you have to use gold-plated contacts on switches and/or relays that are used to hack into the factory A/F signal.

You could still use the mod to cut the time needed to programm your emanage fuel maps by keeping the ecu in open-loop. After you are done then reconnect the wide-band and the car will switch over to closed-loop mode again.

Happy Boosting

Damn Eric you are the MAN!!!!

I was thinking the same thing.. Bravo Eric.. :clap: :clap:

Seconded :clap:

Good info!

so, even with this new tip, dezods black box is still a good thing right? since it will adjust fuel according to boost pressure so you can have good mileage when driving normal? if so, this is still a good tip to tune e-manage. good job!

no, this blows the black box out of the waters!!!

quick someone figure out how to get this to work without throwing a CEL!!!

ya but gas mileage will suffer and i really enjoy having a boosted car that gets me 27 mpg. and ya, the CEL is another reason.

if the black box lowers your afrs (which it does...) you will also get lower gas mileage

only when u build boost. your in vac during normal driving and on the highway, which is where this tuning method has its negative. like eric said, he was running an AFR in the 13's on the highway. with the black box, u can still get your 14.7...

for me, i want the black box for insurance when i have the urge to make a spirited run, but not all the way WOT. ie, for building boost when not flooring it, maybe half throttle or sumthing like that.

i see...

so the black box, is it plug and play? or do we need to tune it aswell?

u can get it with a pretune, however, i think you need to wire it in. it might be easier if you already have the pnp harness and it also needs a vac source.

but yes, this tune method seems like it can help tune your WOT e-manage map.

The black box is better because the ECU will actually control down to the A/F that you want (but only when you are under boost). With the black box The tC ECU will actually work for you as opposed to against you and your MPG will be untouched when you are not under boost. Plus, No CEL's and no failed emission test.

With the black box the A/F correction is already pre-programmed as a funtion of RPM and boost (If you purchase it that way).

I should be getting my black box at the beginning of Dec after the group buy is over. I will then work with this other tool. I think it's going to be the final tool that will allow my tC to operate like a factory turbo car. That will be the day that I say "I'm Done" then I'll look at other stuff to screw up on my car :)

Very interesting post :) Thanks for sharing.

haha awesome... so the tune that comes with the box, is it only for dezod kits? or can i use it for my greddy kit?

Very informative... This will definitely come in handy. Just a reminder that your o2 sensor can become clogged if you leave it in the o2 bung disconnected. That is an expensive sensor and really should be treated well. Now all we need to know are the threads for a small bolt to plug it up when not in use.

A plug wouldnt be at all hard to find.

I'm getting it and I'm N/A. So that can answer your question.

hey eric-tc what would happen if I tried this without fuel management ?


for the plug u can go to an autoparts store and ask for an oil drain plug that is M18 X 1.5 .

what wideband works for this? I know AEM Uego doesnt.

What tasty scan tool is delivering these insights? :D

I dont think it matters which wideband u have , u just need to be able to adjust ur piggyback .

Yhea, I was wondering that too.

sorry read it wrong, damn im dumb.

So do any of the in know tuners such as Dezod have any input on this..? I find it very interesting you can lock the map from self adjusting...

Even if u knew it, would you tell? Also, it's better to do things the right way, no? :D

(maybe stating the obvious here...)
The only thing I think this trick does is that it locks the ECU into open-loop so it CAN'T adjust. Very useful for tuning with e-manage, because if the ECU is bobbing back and forth from open to closed, it's harder to believe what your gauges are telling you. Is that 13.5 AFR at 3000rpm to be believed? Or is the ECU trying to make changes? That sort of thing.

Agreed. Also yes, best thing for a tuner to do is bring good or bad info to the public about a mod when it becomes common knowledge. I would expect nothing less from a good company. However when it is not general knowledge, then a company has the right to keep it to themselves for a competitive edge.

I use Auto-Tap version 3.00 for my logging and a PLX m300 for a wide-band.

I'm currently tuning with emanage-blue with injection and timing capability. I also upgraded to a PSI input by using a GM type 2 bar map that's wired to both my water/meth proportional controller and the emanage pressure sensor input.

There are actually (2) types of closed loop on a tC. Closed loop 1 used for emissions and fuel savings this puts you about 14.7-15.3 A/F. When you decelerate on the tC the ECU does a fuel cut and then keeps the mixture lean this is called closed loop 2.

You can keep the tC open-loop without a whole lot of hassle if you still are rocking with the stock injectors. No correction really needs to be done at that point -but if you are rocking with the stock injectors then you are probably not making that much power anyway.

What's the point of tuning if you have no management. Open loop on the tC is rich on the upper end -I have not tried the lower end under boost without an emanage-map. I guess I can give it a quick try when I get back from the Holidays.

Well, I thought more about this and if I ended up adding 30-45% fuel injector duty while under boost from 2000-3000 RPM's I also added a litte more at 3500. This got me to the A/F that I was looking for during partial throttle boost ( mid to upper 12's) with emanage. This pretty much tells me that you still need a way to add more fuel to the tC even if you are operating in open loop 3 -You need a tune. There is no "magic" way of tuning the tC without loading in your own fuel maps.

It seems the Apex SafcII will now work under the 4000RPM range.

^^^ Single Digit Racing has had the Apex SacfII working for a long time.

Well, I think that this is great information, but I would not recommend running around with your stock O2 sensor just dangling in the breeze and having it exposed to the elements for any amount of time. These sensors are very fragile and delicate, but also EXPENSIVE to fix. Once it breaks and stops reading, now your AFRs are gonna be pig rich and your gonna run a 10:1 AFR.....

I think this may work for a short duration in a controlled environment like on a dyno, but on the streets I would not try it.

Besides, I would not bother to adjust AFRs when not it boost. Partial throttle is where our black box shines and delivers all of the safety and security of a stock turbo car. You can fully customize your closed loop, partial throttle AFRs with it and be done. When in vac, there is no need to adjust anything from 14.7:1, except maybe going to 15:1 for some slightly better fuel economy.......

Very informative post and observation, but once you plug that sensor in.....2 mins later.........ECU relearns. We have noted this on the dyno time and time again. This Toyota ECU is quite powerful.

Do no think you read the post correctly, you unplug the o2 from the harness period. Not unscrew it and leave it dangeling out in the open. That was the point of it :) Second the o2 is unplugged it locks it into what is being noted as open loop 3 so it prevents any auto adjusting.

Maybe I did misread it, but I find this hard to believe. I will have to try this and monitor the differences in the ECU behavior with our MT2500....

Very cool man, that would be great to log what everything is doing in detail. No doubt though... the... black box as it is called is definitly the smartest way to go so you let the ecm handle things under partial throttle. Glad you brought it into the scion world :)

We are always trying to trouble shoot problems in the industry......that is what I have been told I am best at. :)

yes... this is actually possible. i have done this tuning method with my old car (Spec V) and it worked. i had help from the guy name gurov over at myspecv.com he is very knowledgeable car/tech/turbo fanatic guy... anyways... you actually have to unplug both O2 sensors since the 2nd sensor can/might still put you on close loop... what you need you need to do too is to unplug the battery first for 30 mins...
then disconnect both o2 sensors... Also make sure you have a wideband when doing this "tune". once you have unplugged both o2 sensors, plug the battery and start the car... monitor the afr... on cold start, it'll start at 13.1 afr then it will correct itself (ECU) to 14.7 afr... once you are warmed up, this is where you do your tuning. you must have another person reading off your afr while doing this... makes it alot easier to tune... anyways... check this out... this was from my old car...


this is when the car is warmed up... light on the throttle... as you can see its right around the 14.7-15.5 afr
https://i12.photobucket.com/albums/a...eon/afr001.jpg


in this image, i have to tune the low end rpm, since i am not turbo'ed, i should be at around 13.1afr... although, this is pretty close to it..
https://i12.photobucket.com/albums/a...eon/afr002.jpg


this image, i took out a bit too much fuel, i should add a little bit more, but this should be fine for now...
https://i12.photobucket.com/albums/a...eon/afr003.jpg


in this image, it looks like from 4K and up, its stable at 12.1-12.9 afr... this is a bit too rich, this needs a bit more tuning since i am dealing with a wide range of rpm, but i have to do it step by step...
https://i12.photobucket.com/albums/a...eon/afr004.jpg



anyways... this was done in my old car... this was tuned by afc2 and zt-2 to tune my car... i did get the afr i wanted, but i didnt get a chance to do a snapshot of it... if i can find it, i'll post up what my afr was after i tuned it... also, it took me more than a days of tuning to the proper afr i wanted. also, if you guys are wondering where the USER1 is hooked up to, its hooked up to read the voltage of my MAF... spec's MAF is very sensitive, that is why you see all those jagged lines... also, that can be smooth out by doing the boosted afc2 mod. but this is another case.. basically you have to use a GM 2-3bar MAP sensor, MAP sensor wiring harness and then you just have to tap the sensor wire of the MAP onto the throttle wire of the AFC... i think thats how it went... i have to double check... anyways.. once i am fairly modded, i will do this mod once more on my tC.

Interesting stuff. Very informative.

anything new on this??