[bagodoosh]

playing with a carchip e/x today, i observed some interesting things.
brief: this devide sees what the ecu sees. the #s are as accurate as the metering device.

took out two 2000 GTSs on the same road within a 10min span. both have trd exhaust. #1 has stock intake with k&n filter, #2 has aem cai.

after idling at the lite, #1's intake air temp was up to 64.4F. after driving around, the lowest reading was 46.4F.

after idling at the same lite, #2's intake air temp was up to 42.8F. after driving around, lowest reading was 30.2F. (exact ambient temperature unknown, reported mid to high 20s)

i've noticed with cai that air temp remains more consistent thru stop/go driving, where as with stock airbox air temp increases more dramaticaly while the car is stationary.

throttle position on #1: min 11%, max 78%
throttle position on #2: min 10%, max 76%

possible this is just a matter of scaling for the ecu, 10=0, 78=100 ?

at WOT, short term fuel trim = 0%

most adjustment in short term fuel trim seems to happen while speeding with no throttle.

[more to come..]

 

[autxr]

All right, here is the test to do....

On a low tank of gas observe what the maximum igntion advance is over a wied RPM range (prefer WOT runs).

Add some 100+ octane, repeat.

If the timing doens't advance any farther, then we know the 100 octane is doing nothing.

Scott

 

[Boosted2.0]

playing with a carchip e/x today, i observed some interesting things.

throttle position on #1: min 11%, max 78%
throttle position on #2: min 10%, max 76%

possible this is just a matter of scaling for the ecu, 10=0, 78=100 ?

[more to come..]

Its a characteristic of all Toyota TPS readings. In most cases the maximum throttle reading should be about 80%. With the key on, engine off, look at the same reading. Have a friend put it to the floor and record the throttle %. Then operate the throttle bellcrank by hand and record the %. If it will open more when you do it by hand then the throttle linkage is too loose and you are not achieving WOT. I have found that a lot of the time Celicas will not achive full throttle due to a loose adjustment at the cruise control actuator. Its easy to fix though - same adjustment as at the throttle body.

 

[bagodoosh]

sounds good. there's 1 problem.. the device is not real time. it takes samples every 5 seconds and records to memory. since i don't know when the sampling starts, i can't be precise.
ok 2 problems. i can only sample 4 parameters. so it'll be throttle position, engine speed, timing advance, ... that's it i guess. ok 1 problem. :chuckles:

i already sampled timing advance, but didn't record the engine speed. max: 40.5, min: -3.5, avg: 21.5 (14.6mi trip); trip back, max: 33, min: -4, avg: 21.3 (14.4mi trip)

i can do something similar.

 

[Boosted2.0]

All you need to check the throttle is throttle position, and you can do it without even running the engine so the sampling rate is not that important.

 

[Blue Bomber]

Originally posted by bagodoosh
throttle position on #1: min 11%, max 78%
throttle position on #2: min 10%, max 76%

possible this is just a matter of scaling for the ecu, 10=0, 78=100 ?

Yup, that's correct. I'll see if I can find it in the Service Manuals.

 

[bagodoosh]

Originally posted by Boosted2.0
All you need to check the throttle is throttle position, and you can do it without even running the engine so the sampling rate is not that important.

oh yes. that msg was in reference to scott..

Originally posted by Blue Bomber
Yup, that's correct. I'll see if I can find it in the Service Manuals.

i forgot to look there.

EDIT> i just checked and it gives resitance values to be measures with a multimeter.

 

[LilRocketSpyder]

I tune my s-afc with my pocket logger. (Yes the s-afc does work but only in open loop as with any obd car with 02 sensors.) I don't know about your logger but there are setting in the pocket logger software that got the spyder from 4 samples per second to 15 s/p/s. You may read up and see if yours will do the same.

I have found a remote piece of interstate and 3rd gear make for great pulls as the acceleration is somewhat slower than a 1-2-3 pull. It makes the data more useable. Simply slow down to about 2k revs in 3rd and go from there to red line without worrying too much about a speeding ticket.

I record RPM, timing, and 02 voltage. The voltage varies when in closed loop because the ecu is constantly changin the mixture so the data fromt he 02 sensors is useless. But in open loop there will be a steady reading. I shoot for a flat reading across the rpm range down to hundrths of a volt then bump it a couple hundreths of a volt either way to see if I can feel a difference or if it pulls timing I know I am getting knock.

I would also recomend making a couple logs then reseting the ecu and starting from scratch. The ecu will pull timing if a part of the map is too lean and it picks up knock. It will not put timing back in later once it pulls it until it gets reset. So make a couple runs before you reset and see where the timing makes unusual dips. Then add fuel at that range afte ryou reset the ecu. If it keeps pulling keep adding by a % or 2 at a time. If it doesn't take some out but again move in very small incriments.

Don't mess with the low throttle settings on the s-afc as the ecu pulls some voodoo wierd stuff with fuel and timing.


Oh and one more rattle tot his post. Clean your mafs if you have an oiled filter oR all these readings are mush.

 

[bagodoosh]

here is some more info..

car was parked over nite. today coolant temp started at 23F. fuel system operated in Open loop for about a minute. then switched to Closed. coolant temp at this point was 46.4F. i THINK it moves up one notch when coolant temp is over 130F. and if i'm not mistaken i think it reaches operating temp at 175F. my timing could be off (i have to time the events seperately and compare with the time stamps later on).

hmm.. sevice manual states the thermostat valve opens @ 176-183F. but i guess every car differs. the opening temp would be on the thermostat which is not normaly visible.

EDIT> test drive 2:
open loop: 50sec, 28-49F
2 notches: 157F (trip 1), 164F (trip 2)
operating: 177F (trip 1), 181F (trip 2)

i've noticed when the car starts the O2 sensor (pre cat) reads 0. and sometimes during the drive it reads 0. hmm..

 

[bagodoosh]

and yet more (even though it seems i'm chating with myself)

another drive revealed the 1st O2 sensor, S1 (pre-cat) is operational sooner. celica uses a heated O2 sensor. i believe they have to reach 600F to operate. in this case, it took S1 about 25 seconds. this is when the ecu kicks into closed loop. the 2nd O2 sensor, S2 (after cat) took a little over 2 minutes.

i was looking at the differences between S1 & S2, and they are rarely the same. some of you may nod your head, obviously! well, then this means placing an A/F sensor at the exhaust pipe is not accurate. again, with the nodding.. this is against what i was told by a dyno shop, that they had placed an A/F meter before and after cat, and the readings were so close that they concluded the reading at the exhaust pipe is just as accurate.

so i did some research.. a catalytic converter's job is to:
turn HC into CO2
turn CO into CO2
turn NO into N & O
so it is entirely possible that pre-cat there's less oxygen, and after cat, there's more, and vice versa.

so i went for a 37 min drive, sampled S1 & S2, calculated the difference, as S1-S2, and graphed the result:

:wiggle:

 

[LilRocketSpyder]

s2 should be more stable as it doesn't see as much of the close dloop mixture changes.

S1 should be used for tuning. Temperature can effect the readings of a stock 02 sensor. If it is post cat you are gambling.

 

[143hawaii]

Originally posted by autxr
All right, here is the test to do....

On a low tank of gas observe what the maximum igntion advance is over a wied RPM range (prefer WOT runs).

Add some 100+ octane, repeat.

If the timing doens't advance any farther, then we know the 100 octane is doing nothing.

Scott

I'm not sure about the GT-S ECU, but I've already done this with a Spyder's 1ZZ. Results, the ECU isn't smart enough to advance ignition timing to take advantage of the increased octane. Also, as many Spyders have said, S-AFC IS effective during open loop (WOT) conditions.

 

[bagodoosh]

Originally posted by autxr
All right, here is the test to do....

On a low tank of gas observe what the maximum igntion advance is over a wied RPM range (prefer WOT runs).

Add some 100+ octane, repeat.

ok, i have done this, although i did it with 91 vs 93 octane on my car & compared with another car running 93 octane.

i thought spark timing is related to engine speed, but i do not see the relation unless there are other factors involved that mask the relation. i also compared timing with engine load and again found no relation.

the most timing advance i noticed was before car reached operating temp. 35, 38 degrees.

however once the car reached operating temp, the max timing advance recorded was 33! both 91 & 93 octane. i could test on 94 octane, but if 93 doesn't make the difference, i think i'd save my money on 94, or even 100+.

for what it's worth, the average timing advance on 3 trips was about 22.

and since i like graphs:

red : 93 octane, mobile (my car)
green: 91 octane, pace (my car)
blue: 93 octane (another car)

 

[LilRocketSpyder]

Did you reset the ecu before you switched fuels?

 

[bagodoosh]

no. is that necessary? wouldn't you think it'd adjust over 15 miles if it detects knock?

 

[Sirk_2]

Resetting the ECU is crucial for it to realize the different fuel.

my question is this: you state that max throttle is only around 78%...when I had my SAFC, that thing would read my throttle from 0%-100%. Now was this accurate or not? Is there still more power out there to be had?? This is quite startling news to me. To think that your car not reach its potential due to the fact tha Toyota did not release its car w/ full throttle, or even close to full throttle.

 

[LilRocketSpyder]

You will see your highest timing right after a reset. That is why it feels stronger after a reset. I don't think the learning ecu will add timing back in. IF it does it takes quite a while to do so. A reset is the fastest way to get max timing then see if it pulls any becasue of knock with your logger.

The TPS scale is self calibrating. It won't read 100% even though 75+% is full throttle. And 12% is fully closed. You used to have to calibrate a tps before obdI cars IIRC. It is doing exactly what it is supposed to do.

 

[vvtlikick]

no. is that necessary? wouldn't you think it'd adjust over 15 miles if it detects knock?

I think it might depend on what order you use the different octane fuels in. If you use low octane before the high octane, the ECU might still be retarding the timing when you switch to the good stuff.

I don't know how long it keeps retarding timing, however.

 

[Boosted2.0]

You will see your highest timing right after a reset. That is why it feels stronger after a reset. I don't think the learning ecu will add timing back in. IF it does it takes quite a while to do so.

This is absolutely correct. I haven't confirmed it on a Celica ECM, but on a GS400 with VVTi it would not advance again for literally weeks if you put in low octane and it retarded the timing. You had to pull the battery for 5 and it would reset only then.

 

[LilRocketSpyder]

You want it to advance the timing for the higher octane.