Low idle??

[JetspeedCamry]

Over the past few months ive noticed my car idles a little low at cold start.
It is supposed to be around 1500rpm, nowadays its around 1100, and quicly finds its way under 1000 before the needle has moved that much. Note that if I reset my ECU (discon battery or EFI fuse) then it works fine (idles @ 1500) the first time only, but then everytime thereafter, it goes back to this lowly idle.
I've replaced the ECT sensor (which was stuffed!! and it didnt make any difference after changing it! ) and oiled the IAC bearings with a light machine oil in case they were sticking. Nothing has made a difference.

My question is, what other things affect the idle on cold start like this? And why does it work so well after an ECU reset?

The car still starts fine, so that sorta ruled out the CSI switch. I was thinking maybe just an old/worn IACV, but, internally, it doesn't look like it could "wear out". The car also idles funny somtimes at normal operating temprature. Clutching in, the revs sorta bounce slowly a bit, down to 600 then up to 700 then back again until it equalizes at 700 (which is normal idle speed).

Any help would be appreciated

[takai]

Sounds like the IACV/ISCV is getting overdriven, so basically the ECU is asking it to open more than it physically can. Try turning up your idle slightly via the idle screw and see if it makes a difference.

Doesnt quite explain the ecu reset differences though.

[TRAV-KE55]

Im not sure about the V6 camry but the 4cyl ones have a wax pellet (similar to thermostate) cold start idle air bypass, it is naturally open then as the water temp rises it closes of the air bypass, usually mounted on the throttle body, it has 2 small water hoses going to it. As for testing it you should be able to take it of and sit it in hot water and watch it close. It sounds to me like it might be seized. just a thought.
Trav

[JetspeedCamry]

Thanks for the replies.
I've never seen this wax pellet thing, i'll take a look around the TB and see. I know for sure that it has 2 larger coolant hoses going to it, but i thought that was for Coolant Bypass.

Takai- Unforuntately, the 2VZ doesn't have any manual idle adjustment (standard atleast). Theres no screw, unlike the 3S engines which do. BUMMER! I need to a way to trick it

Any other suggestions? Anyone think it could be a faulty ISCV?

[mic*]

Get your injectors cleaned.

The ECU knows how much fuel should flow, but quickly works out how much is flowing.

Its supposed to run rich when its cold. Maybe your not getting good fuel delivery and the ECU is holding back the air flow through the ISCV to compensate? Its running lean when you reset your ECU until the computer can fix it somehow.

At normal op temps leaner mixtures make it less noticable.

Got or got access to an AFR meter?

[JetspeedCamry]

Get your injectors cleaned.

The ECU knows how much fuel should flow, but quickly works out how much is flowing.

Its supposed to run rich when its cold. Maybe your not getting good fuel delivery and the ECU is holding back the air flow through the ISCV to compensate? Its running lean when you reset your ECU until the computer can fix it somehow.

At normal op temps leaner mixtures make it less noticable.

Got or got access to an AFR meter?

Thanks for that adivce, i'll get right onto that. Would you recommend a liquid cleaner (put into tank) or complete removal/overhaul by a fuel injection specialist.
I have a narrowband Autometer AFR meter, but that doesn't really show much, and isn't working at the moment. (I think i blew it while jump starting the car...!! maybe i blew my O2 sensor aswell!! haha).

[mic*]

I reckon most of that wynns spitfire & related products do an excellent job of prevention.

Not so good at cure. They will increase flow a little but id probably suggest getting em professionally cleaned.

Make a few calls to FI shops. If you find a good one they will let you take them down there (you have to pull em off youself but it aint that hard) and flow test them for free or for next to nothing. They will compare this to the factory rating of the injector and tell you if its badly fouled or not.

Cleanin if needed should then cost about $20 - $30 per injector.

O2 sensor you should get fixed if forked. Mite not have much affect, but can affect mixtures at times, i think cruising is one? If you did a lot of this you will get bad economy foul up your motor a bit quicker.

[JetspeedCamry]

Fantastic. Thanks for the advice. Ill get this done after chrissy.

[deeps]

Autopro does the cleaning for $17.50 per injector. Ultrasonic cleaning with new seals etc. i believe.

I'm going to get mine done, as soon as i work out how to get the injectors out. I'm pretty sure i've worked it out, but is it easy to put them back? (3s,4s,5sfe engine)

On a side note, how much will it cost if i take it in to a shop and get them to do it completely? If it'll just be an extra $30 or so (one hour labour?) i'll just get them to do it

[mic*]

Injectors are usually always just pushed into the rail with a rubber o oing securing them, unless you have built a REALLY high boost engine.

The hardest part about getting em out is getting everything else outta the way. i wouldn think there would be more than an hour or two labour in it.

[deeps]

hmm ok i've managed to get everythin out of the way, now, i have to move the fuel rail back i think, so i can pull the injectors out. How do i do that?

Also, i can't seem to get the wiring off the injectors, as the plastic has hardened heaps over the years. Infact, that's a trait all over my car, all the plastic plugs have hardened so much, it makes removing them very hard. Any suggestions in getting them out easily?

[mic*]

Without looking at it i am not gonna be able to help much with the rail.

Make sure the fuel system is de-pressurised, i know that is obvious but it happens. It should more or less just unbolt from the lines and pull off...

Not sure what clips you have either. Sometimes there is a sur-clip which can be somewhat hidden. Otherwise look very closely, be patient, and work out how the clip is meant to come apart. Many a time have i lost patience with wiring connectors... but it doesn pay to.