AFR Problems

[thedave925]

The maft-pro uses its IAT sensor in combination with it's MAP sensor and enters the readings into the equation that makes speed-density possible, then out puts the results for something the ecu can read, which for the toyota supra mk3 ecu, is in hertz.

The brown wire from the maft-pro is the temperature output wire that ecu looks for.
Because the maft pro is slower to boot up than the ecu despite hooking it up to either ACC or ON power leads from the Key Ignition switch, it becomes necessary to use the resistor in the old afm wires to hold over the ecu until the maft-pro fully boots up.
Remember the 'Vol Setting 1' menu and you entered 2.4, thats one of the values the ecu looks for but doesn't see soon enough at start up.

So the brown wire supplies the ecu with a temp signal, the resistors makes codes 24 and 32 from startup go away, and the ecu throws codes making it hard to drive even if it does self resolve temp to 65.

Keep firing away with questions, this is the best way to learn

 

[loki2043]

hmm, I've been driving the car like this for a couple years now :/

So now if i put in the resistor to ditch the codes, will the ecu still only revert to ONE temperature? like say now it resolves to 68 when it dosent see anything, well when i put in the resistor is it just going to make it stick to a constant 75? or will it now allow the maftpro to provide and update the ecu with the correct temp?

one more thing, is hooking up the maftpro to ACC power lead necessary with use of the resistor?

 

[strippedsup87]

^ what do you tune with?

sounds normal, mine goes rich for a split second and then lean if i stay out of the gas. The split second of lean when you hit the gas sounds like the injector correction (term?) that jdub has mentioned. ill see what i can dig up...

For the truck we used to tune with the split second psc 001 but now we tune the truck with the Diablosport Predator and cmr tuning software.....Makes about 525 hp....

 

[thedave925]

hmm, I've been driving the car like this for a couple years now :/

So now if i put in the resistor to ditch the codes, will the ecu still only revert to ONE temperature? like say now it resolves to 68 when it dosent see anything, well when i put in the resistor is it just going to make it stick to a constant 75? or will it now allow the maftpro to provide and update the ecu with the correct temp?

one more thing, is hooking up the maftpro to ACC power lead necessary with use of the resistor?

You can select to on the maft pro to hold one temp, so it would put out that many volts using the brown lead. And if you use the resistor method, you don't even have to have that brown wire hooked up.

And the ECU will modify the maft-pro's signal according to whatever temperature you fool it with using the resistor.

You don't have to move your +12volt power lead for the maft pro to ACC from ON because you have the resistor in line of the AFM wires, which tell the ECU that there is voltage and not a broken circuit at immediate key on before the maft-pro can boot up.

One thing I'm glad of is that it sounds like you don't have any boost leaks, which make tuning a lot easier after you take care of codes

-Dave

 

[loki2043]

okay, maybe i am not getting my point across. How big of a deal is it for the ecu to stay at 1 tempature? does it not matter if i have it updating or not? if it dont mean shit i will go put the resistor in. but im not getting an answer as to weather this is important or not.

 

[dumbo]

thedave925 are you saying if you dont fix those codes tuning will be hard? I thought they wouldn't effect anything?

Anyways I don't want to thread jack but figure it'd be good to keep this together.

I'm running 87na-t maftpro spd dens. I got codes 24,31,32,34. It's like my cars AFR have a mind of there own. I'm running PTT stock o2 unplugged but its not throwing a code for my o2 heater and if i plug my stock o2 it doesn't change anything!?!:aigo:

so for code 24 and 32 i put a 2.2k ohm resistor on what wires if i'm looking at the afm plug?
31 is my HAC and i know where to put the resistors for that
34 is abnormal boost pressure, how would that even come up if i'm running spd density??

thanks for the help.

 

[thedave925]

Code 24 w/maft pro <---Best Maft-Pro Thread Ever :biglaugh:
It has details including the difference between the GE and GTE ecu.
Ohm values, voltages, concepts, reasons. Even the last post is about how JimR plugs his resistor straight into a plug (is that where i got the idea from??) LOL

Loki:

What is important is to prevent codes.
What temperature is read is important in the respect of preventing detonation under boost.

2.2kOhms was used to pick about 68* for 'the turbo guys' (MaftPro and TCCS Diagnostic Codes) so that the ecu doesn't max out one way or another according to the translations of the maft.

I saw your maft pro settings from another thread titled 'maft pro-timing control and more', post 19 from 10.28.08
Are you still using those settings?




Dumbo:

I only became happy with the maft pro after resolving my code issues.

I actually run the stock nb o2 sensor still hooked up to the ecu since i couldn't successfully complete the heater circuit with a resistor or manage to hook up the nb simulator from my lc-1 trouble free.
Having these codes made tuning very hard and waste lots of fuel.
I was compensating with ptt too but it seemed the more gain i added the worse the afr stability was.
I fixed my codes and just got done doing a 600 (mostly hwy) mile run with around a tank and a half, including boosting my way up and down hills and the fun twisties i could find.

24 and 32 are directly related to unplugging the afm and not having it there for key on, hence the resistors i'm blabbing about.

31, i'll let someone else chime in on that since i'm not very familiar with the flapper system afm for n/a. Refer to top link, Code 24 w/maft pro, post 9

Perhaps you followed the wrong wire diagram for your car year?
Is your ecu for a 7mgte?
You do have a wideband o2 hooked up right?
Did you calibrate it?
Are your grounds for the maft pro, ecu, and wide band where they belong?
I have no idea why code 21 isn't coming up when you have your o2 sensor unplugged.
Double check your wiring.

What happens when you are running with those codes is that your AFRs will always be 12.5-10.5 rich, Vf showing 0. You can't get a solid tune not knowing what the ecu is thinking. Ptt cannot manipulate the output of the ecu successfully when the ecu actively take whatever hertz you give it and richens. Kinda like guessing if you pick 20afr with ptt, will it go down to 14.7 all by itself, predictably, everytime you hit the throttle and let off? It never settles, so the goal is to eliminate the codes.

Check out this site, very helpful on detailed hook up without all the distractions of others' dialogue:
MKIII Supra - Electrical References
I believe CRE actually set it up, thanks to him for providing specifics.
Many many people took they're time to figure out work arounds, you'd be amazed at how many people contributed to just the maft pro since '05...

 

[dumbo]

Sorry I should of told you I have 100&#37; GTE eletronics from a 87-88.

Why I don't get a code 21 with the o2 unplugged, and why the stock o2 doen't do anything is confusing the hell outta me.

Code 31 i'm buying resistor today for the HAC.

And code 34 I dont get either, how would it even know there's a boost leak running speed densisty??

EDIt: I've messed around with my settings lots since then, that was the first day I got my car running after the n-t.

Edit: I just read that CRE said if you got a vf voltage with the stock o2 unplugged you got a problem...and i'm sure it ha sometthing to do with my no code 21.

 

[loki2043]

okay, ill put the resistors in and check back in. i am also gonna adjust the TPS to rid code 51 and then check my timing accurately.

 

[loki2043]

Dumbo, it sounds like you may have a bad wiring harness or ECU. :/
do you have access to another ecu?

 

[JimR]

Chiming in here....

For everyone: Just so we are crystal clear on this, you use the Vout1 and Vout2 wires from the Maftpro, OR you use resistors. They take the place of eachother. Resistors are preferred.

Loki2043: If you have Vout1 from your Maftpro going to THA, then your Vout1 voltage should be set to 2.5 volts, not 5.00 volts! Your Vout2 voltage of 3.6 volts is correct.

Also, when you're posting the log spreadsheets, can you select all of Column A and do a 'Text to Columns' conversion with comma? It makes things much easier to read. Or just leave the file as CSV format.

Third, can you confirm you have 'F out Max' set to 0? That 'Airflow limit' of 1023 is unnerving me.

Dumbo: I replied to your Code 21 thread.

TheDave925: What happened when you tried to use the resistor with the O2 heater circuit? What didn't work?

Cheers all!
Jim

 

[thedave925]

JimR: Thanks for pitching in.
I chose the wrong wire to add the resistor, or had the wrong value resistor.

 

[JimR]

JimR: Thanks for pitching in.
I chose the wrong wire to add the resistor, or had the wrong value resistor.

Hrrrmmmm. Well if you try it again, the first thing I'd do is stick the resistor straight into the O2 connector in the engine bay. Check the contacts with a voltmeter to be sure first, but I believe they are the two that are closer together.

Here's what my O2 connector looks like on the sensor side. Hope that helps.

 

[paradox616]

isnt the o2 a narrow band??? if so why are you trying to tune with it???

 

[JimR]

Plug in the HAC. I have a 90 and left mine plugged in, never did the mod to the ecu and everything is fine
.............

Fine, besides doubly compensating for altitude, lol.

 

[JimR]

isnt the o2 a narrow band??? if so why are you trying to tune with it???

We're not. AFAIK we all have widebands. One of the questions here is whether we run with both wideband and narrowband sensors, retaining closed-loop ecu control, or whether we ditch the narrowband input and run permanent open-loop.

 

[paradox616]

We're not. AFAIK we all have widebands. One of the questions here is whether we run with both wideband and narrowband sensors, retaining closed-loop ecu control, or whether we ditch the narrowband input and run permanent open-loop.

why not just run a analog output from the wideband to the ecu? and good

 

[JimR]

why not just run a analog output from the wideband to the ecu? and good

Because then we can't do any fun stuff, like using the Maftpro Part Throttle Tracking features, lean cruise like 16.0:1 AFR, getting rid of the lean spike right before 3500rpm/70&#37;throttle, etc etc

 

[dumbo]

Fine, besides doubly compensating for altitude, lol.

LOL!!! How was that missed...

 

[loki2043]

I will work on these issues later, I am tearing down the engine next week. I believe I have a blown head gasket.