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

[BigWorm]

I'm currently looking into an aftermarket ECU for the Cressida, but mainly in the interest of fuel economy. It currently gets around 14L per 100km around town, then seems to be similar or worse on the one decent road trip it's had, which was Adelaide to Sydney & back. Now I can almost cop that for round town driving (ie. chopping bogans) , after all, it's a factory turbocharged Toyota motor, 10:1 A/F ratios are par for the course. but for a close to 3000km round trip to Sydney & back, totalling 420L, times an average of $1.50 a litre, there's not enough K-Y in the world to make that a smooth & pleasurable experience! (Especially considering I work for Qantas & can fly for a fraction of the price of all you plebs ) A figure I found on PlanetSoarer talks about 10L per 100km for highway driving. I want some of that!

So anyway, I've been investigating an ECU for the old girl, & one of the things mentioned by a workshop I spoke to was the chance that the standard ECU wasn't actually going into closed loop mode. So I'm wondering if there's a relatively simple way I can determin whether it is?
Are there error codes I can look for?
I havn't had alot of luck on my inernet searching.....

[Hydra]

Well, if you are getting an error code then that is a start!

I haven't really had a chance to play with a 1JZ yet, but it kinda sounds like the basics might need taking care of first. Have you checked the plugs? Timing?

[BigWorm]

I havn't bothered looking for error codes, as I have no reference to decifer the codes.
Plugs were good, obviously a little rich looking, I changed them while in Sydney. I don't see why the timing would be out?

[Forcefed6]

Check for error codes... Something like a faulty oxygen sensor could cause this.

[oldcorollas]

. So I'm wondering if there's a relatively simple way I can determin whether it is?
Are there error codes I can look for?
I havn't had alot of luck on my inernet searching.....

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.

that help?

the aftermarket O2 sensor gauges (usign narrow band) do this. you could easily get one of those cheapy jaycar 10 LED bar things, just so you can see the voltage going up and down easier....

[BigWorm]

Sweet, thanks stew. That I should be able to manage.

[BigWorm]

So when it comes to error codes, are they the same/similar for all Toyotas?
The cressida's the first factory ECU car I've owned, this'll be my first time checking codes.

[EvilJack]

say hello to my little friend...

ECU Diagnostic Codes

Trouble Procedures

[BigWorm]

Ahhh, bloody fantastic, that's what I'm talking about!

I'll play with it today, & post up any results.

[ProjectSleeper]

I get around 9L/100km from my 2JZ on a trip (average spped of about 115=120km/h)
it drops a little below that when sitting on 100-105km/h.

When Dale (www.braidedlines.com) dyno'd my car and set all the electronics up, he made sure that the lean cruise mode was untouched and hence I still get awesome economy.

Around town is closer to 12.5 to 13L/100km

You should be getting better than 10's on a trip.

[takai]

Far out, my stock 7M gets 12L/100km on a long trip. 14L/100km round town. I think i need a 2JZ.

[urantia]

ProjectSleeper, thats pretty decent! what diff ratio do you have?

I achieve about 11L/100km with a 4.3:1 diff with highway driving, i don't like revving at 3000rpm for 100km/h

[BigWorm]

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.

[ProjectSleeper]

Factory Cressida LSD.. 3.91:1

The main thing is the 2J has ooodles of torque, so you don't have to rev it much or use much throttle when taking off from the lights.

[EldarO]

22-23L/100k's here, everything bog stock except for a K&N Stock replacement filter, and a 3" cat back.

i think i have some serious issues!

Eldar.O.