Ecu reset procedure.....

[Pride]

Having watched your erratic idle video a couple of times is it possible you’ve missed a slight air leak somewhere, I’m sure if anyone on this forum would diligently check all possibilities then it would be you but from what I’ve seen and read there are many places the air leak could come from, O rings, gaskets, joints or even slight hair line fractures.

What a nightmare symptom you have. 😰

[goldnsx]

If you think it's an air leak somewhere you could use a fog/smoke engine in the intake and pull and twist on all hoses. What about the injectors and injector seals?

[Kaz-kzukNA1]

Watched your video. That's not even staying within the idle control region, lol.
ECU will re-learn something but don't know what will happen within the idle control window.

Similar to another factor causing EACV to hit its max/min limit and ECU just compensating it back and forth or you have other issues.

The TH butterfly should be at constant closed position for non-DBW spec.

AT selector signal sent to the ECU has to be constant during the process.

Fuel pressure should be fairly steady even with your rpm behaviour.

You could disconnect both F & R O2 sensor connectors to force the ECU into open loop.
This may or may not prove anything if the engine getting extra air intermittently such as cracked vacuum tube changing the amount of external air with engine vibration.

Just a matter of interest, where about does the base idle air adjust screw at the TH body sit from fully closed position?
I won't touch it as you may have other issues and adjusting it without fixing other issues first will introduce new issue/factor later.
But, with thoroughly cleaned TH body, for both the non-DBW and DBW model, somewhere around 3/4 opened from fully closed position is a good example.
That's how the TH body left the factory.

Probably you have already seen other examples but this is what you would see during the reset sequence on non-DBW model.
DBW one would behave slightly differently at the beginning but as mentioned below, once it reaches the target idle rpm, it will be the same.
Please ignore the temperature gauge as my sender unit has problem (incorrect resistance and slow response) for ages.
Just waiting for the next coolant service.

It's boring once it reaches the targeted idle rpm (depends on the MT or AT) so I just shortened the video as the rpm just sits at the target for the rest of the process.
Couldn't position my gymbal through the steering wheel so apology for the shaky video.



Kaz

[goldnsx]

OT and just curious: what is the red symbol in the lower center of the instrument panel. I haven't seen this before.

[Kaz-kzukNA1]

OT and just curious: what is the red symbol in the lower center of the instrument panel. I haven't seen this before.

Mine is JDM so different from European spec.
The beep and that indicator immediately after IGSW P2 ON are the seat belt reminder.
Introduced from Nov/92 model in Japan.


Kaz

[britlude]

right.. latest investigation results....... when i got home from work the idle was about 1000, with the occasional rise and drop, not as bad as the previous vid... with it running i did douse anything that could have a vac leak with carb cleaner hoping to get a reaction, alas no, so disconnected the ECAV to see what happens.... idle nice and stable, adjustable with the idle screw....



if you multiply the Hz on the multimeter by 20 you get the rpm.... so i can wind it down to 37hz or 740rpm and no lower. i would expect the engine to be able to stall on the screw.... i did block the pcv valve, and it dropped a little to 660rpm, ..... but rose with the pcv valve released again,so some air getting in there as expected...

so no obvious leaks, so it could be the fast idle valve not closing completely, which is a possibility, or the ECAV leaking a little air past...

reconnecting the ECAV valve, the ecu controls the engine speed, the idle lifting again to about 1000rpm, so that is doing something. if i alter the idle air screw (so many idle air circuits!!) the ECAV tweaks to keep the revs about the same regardless of whether the screw is closed or not, but with the occasional rise and fall....

a little percussive maintenance on the ECAV (ie. tap it with a metal stick!) and it seems to be a little happier, so suspect that might be being a little sticky too, given the soot that was on the idle screw when it came out, i wouldn't be surprised!

so, to that end, i have a new fast idle valve, new ECAV, AIT sensor and pcv valve from Amayama, along with a full intake gasket set, so it'll get removed, cleaned, internal butterfly screws checked and all put back together!



as it stands at the moment, restarts like this..... with gear selection too....



so, better, we'll see how it behaves for the rest of the week!

i shall put a new idle screw in too, just to complete the intake set! just got to find one that's not on a silly lead time! (16016-PM6-005... same as a del sol!!!)

[britlude]

Idle screw should be with me Saturday!!!

[britlude]

I shall be looking at it this week when I get a chance, but I can completely close the idle screw and the car will still run. I presume u should be able to stop it as the engine 'shouldn't' be getting any air.....

To that end, I have a new fast idle valve and EACV ready to go on along with pcv valve and AIT sensor... I'll try the easy bits first.....