1JZ- how to tell it's going into closed loop?

[JustCallMeOrlando]

I'm black and I know it, I take my big booty and show it.

[2JZR31]

I get 10.1 on the highway and 11-13 around town.

[Wildsupra]

to test if your OXY sensor is actually working (closed loop) whilst in cruise conditions.... hook up an AFR gauge to it - it should swing back and forward from rich to lean

WITZL.... your still alive buddy, saweet, all this talk of fuel consumption and big draggy bodykits has triggered my memory PM sent dude

Matty

[BigWorm]

well, Ive been through a couple of tanks of fuel now since changing O2 sensors, and I've had no change in economy.
Anyone got any ideas or clues as to what might be causing this, and how I can go about fixing it? Preferably without just going straight to aftermarket ECU? (which I am looking into still, but would prefer if I didn't have to, obviously)

[The Witzl]

measure the voltage you are getting from the Oxygen sensor pin on the ECU. When you are cruising (or at idle once engine at operating temp) it should go up and down pretty regularly - this is how you test that the engine is running in closed loop.

Toobs' 3S-GTE book, as well as the 4AGE book available on the Toymods repository has information about measuring the oxygen sensor voltage..... READ IT.

[BigWorm]

yes... when it is in closed loop, the ECU will add or subtract fuel every second or so (going from vague memory) anyway, the result is that in closed loop, if you put a multimeter (red lead) onto the signal pin of the O2 sensor, and the black lead to the ECU ground.... you should be able to watch the voltage swing from maybe 0.2/0.3 to 0.7/0.8 every few seconds...

if it is just staying around 0.7, it is stayign rich.

Stewy, you're a legend, and deserve every one of those 700+ rep points!
I got the multi meter onto my o2 sensor and it wasn't giving out more than .1 of a volt, instead it was hovering around .02 to .03. So I tried my brothers o2 sensor off his 2J, and it did exactly as you described, fluctuating between .2~3 to .7~8. So next step is to fill her up & see how many kms I get.
Oh, & find my brother a new o2 sensor.

Speaking of reading things....

[The Witzl]

Speaking of reading things....

you know im dislextic and irritalert...... plus this thread is too long.

Did you measure it at the ECU pins as well?
It's entirely possible that the shielded signal wire from your ECU to your oxygen sensor is up teh wang.
Is it a 4-wie heated ooxy sensor, or just your regular plain jane single wire jobbie?

I rekon you've wanged it, cos you love teh wang.

[BigWorm]

At the ECU pin??? Damn, that sounds like alot of hard work.... You really reckon the wire could be fuxored? When I tested it the wire was still hooked up to the ECU, so I don't think it had shorted out to the sheild. It's a 3 wire sensor, and the wire from the sensor to the plug is not shielded, & the wire coming out the other side of the plug didn't seem to be shielded.

And WTF is irritalert??? Irretarded I'd say!

[The Witzl]

irritalert = fubared dyslexic version of illiterate.


it's possible that the wire is fudged, yes. Hence my suggestion of checking it down at the ECU end. Do some basic tests of the oxy sensor wires in the wiring loom - unplug the sensor and the ecu, and resistance between oxy signal wire and E2 then E1. Then check for resistance between the signal wire and the heater power wire, and between heater power and E1/E2.

It's possible that you might have the oxy sensor signal wired to the heater power or something like that. The lack of shielding could also potentially be an issue....

[BigWorm]

It's possible that you might have the oxy sensor signal wired to the heater power or something like that. The lack of shielding could also potentially be an issue....

Hey c'mon, I have more faith in Mos' wiring ability than that! With regard to the lack of shielding, I imagine the O2 sensor to ECU wiring would be standard & unmolested.
I guess there is a chance somewhere the wiring/insulation has deteriorated or been damaged, so I'll have a play with it (once Jesses 2J shenanigans are out of the way), but I reckon there'll be more to it.

[The Witzl]

Hey c'mon, I have more faith in Mos' wiring ability than that! With regard to the lack of shielding, I imagine the O2 sensor to ECU wiring would be standard & unmolested.
I guess there is a chance somewhere the wiring/insulation has deteriorated or been damaged, so I'll have a play with it (once Jesses 2J shenanigans are out of the way), but I reckon there'll be more to it.

Ah - i forgot it was Mos wired! Well forget my comments about il-conceived wiring connections, it's more likely to be something that has died rather than incorrectly installed.
Perhaps there isnt a good current path from the exhaust manifold to the chassis?
Maybe the OX input on the ecu has died in the explosion?
Maybe it doesnt like you?

[gerald1]

my 4a-f gets 13L/100km

i need to stop driving to school, those crappy 2km trips to and from school are hurting me :'(

is there something wrong with my 4a-f?

gerald

[JustCallMeOrlando]

Yes...yes there is. Even caning the bejesus out of it shouldn't use that much.

[gerald1]

i know, and i drive like a grany almost everywhere. it pisses me off!!! i had a thread about it asking if it could possibly be my fully sick gangsta exhaust and everyone said its not likely cos its only a muffler.

anyone got any ideas:
p.s. sorry for thread hi-jack
pp.s its not my o2 sensor as i dont have one!

gez

[The Witzl]

your 4af needs tuning.... BADLY!!!

my old 4afe was the uber economaster..... i used to get 500kms to 35L thrashing the bejeebus out of it through peak hour traffic going to uni and work.... and then i'd get 550-600km/35L on the highway...

... my record economy drive was Castle Hill to Grafton - about 650km on 36L.