Jump to content
SAU Community

Idle Problems Rb20Det

D.I.Y. Mik

By D.I.Y. Mik,
in General Maintenance

 Share

Recommended Posts

D.I.Y. Mik Veteran

D.I.Y. Mik

Posted
Posted

So i cleaned out my aac valve and its still hunting at idle and dipping a lot with power loads(fan, steering).

When i first got this car i didnt know about setting the idle on the aac valve and i used the little screw to open the throttle slightly.

Does the throttle need to be fully closed/sealed for it to idle properly? Is this in effect an air leak as far as idling is concerned?

Also the computer idle screw is set to full low, all the way counter-clockwise.

Link to comment
https://www.sau.com.au/forums/topic/397139-idle-problems-rb20det/
Share on other sites
ima_slap_joO Collaborator

ima_slap_joO

Posted
Posted

Hey mate, first you will probably want to check your TPS is set correctly, so just double check that is reading .48 volts at idle, if not adjust and reset the computer. Once that is set, if your IACV needs adjusting you should just be able to turn the idle control screw and this should alter the idle speed as soon as you start turning, if this does not occur you may have an issue with the oxygen sensor (my IACV would not alter the idle speed AT ALL with the oxygen sensor plugged in, turned out it was not wired correctly, but once disconnected or wired correctly, the IACV once again had become operable with the idle screw). The screw head should only need to be pretty much flush with the outermost part of the housing, not in too far or out too far. Just make sure you give the IACV a really good and thorough clean as once the carbon builds up on the black diaphragm this adds friction and does not allow free movement once the valve is moving.

You should also return the throttle? screw to the standard position, the less variables, the more likely you are to find the actual problem.

Why did you clean the IACV? Did you have idle issues previously or? I had idle problems for close to a year, both the TPS setting and the 02 sensor had a massive part to play in rendering the IACV useless, only once I had both the TPS and 02 sensor working correctly did all the idle issues go away, but it was instantly, as soon as the other interferences were gone.

D.I.Y. Mik Veteran

D.I.Y. Mik

Posted
  • Author
Posted

Thanks thats helpful, but..

How do i test the tps? (.48 v from where?)

Also the idle does seem to adjust slowly (delayed reaction). So theres an issue somewhere.

Can i clean my O2 sensor?

Ha! this is like science, the answer to one question leads to two more questions and so on ad infinitum.

Ps. thanks for help.

ima_slap_joO Collaborator

ima_slap_joO

Posted
Posted

Hey mate, the TPS throttle position sensor is a little black box with a plug which sits on the throttle body, there is a plug right facing, and three wires which come out the bottom of the unit, you need to measure the voltage beween the middle and right facing wires of the three wires out the bottom, it should be around .48v at idle, and move up to around 5.v at wide open throttle, if you havent played with this it may be ok, you can also test this on reds without the car on. The valve you are playing with at the back of the plenum there is the idle air control valve, and you will need to ensure all the soot is gone before trying again, take the whole unit off, including the silver housing and give it all a good clean. You can unplug the 02 sensor while trouble shooting the TPS and IACV.

ima_slap_joO Collaborator

ima_slap_joO

Posted
Posted

Yes always had idle issuesWhat exactly is the IACV? is that the AAC?

Theres no diaphragm in my AAC, just a soleniod, spring and valve.

it must be the old type.

May have used the wrong term haha just clean everything, and ensure its back together properly.

D.I.Y. Mik Veteran

D.I.Y. Mik

Posted
  • Author
Posted

Ok, closed the throttle completely, re-adjusted the idle on the aac(iacv) now its fine, responds well to power loads and no hunting.

Tps must be ok too, thanks for the exact info on how to test.

That info should be saved for others. or put in diy/faq.

thumbsup.gif

I read somewhere that SAU is the best skyline resource on the web and if you search you know its true.

D.I.Y. Mik Veteran

D.I.Y. Mik

Posted
  • Author
Posted

Its still playing up! dagnabbit.

On a cold start it idles at 1100 then over a minute it climbs to 1900 then drops suddenly back to 1100.

If i restart it idles at 850.

thats bad for a cold engine, i can hear funny noises when i switch off to restart.

Any ideas? im stumped.

ima_slap_joO Collaborator

ima_slap_joO

Posted
Posted

Hey mate, I believe that is just the engine attempting to reach operating temp quickly as possible. Let it warm up, allow it to drop to 1100 RPM then adjust the IACV. I actually idle at around 1000 RPM anyway, helps with the brass button clutch and stalling. BTW, have you still got the original BOV working or replaced with after market atmo BOV?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • PranK
      Chris' Toyota Mark ii JZX110

      By PranK · Posted

      This looks great! Awesome to have the 5 speed with an LSD in this. The Recaro's look like SR2's or SR3's. It's a shame they've been retrimmed as they would have looked sweet in their original colours. I think I'd want my agent to be a little more up front and informative too. I've never imported but I reckon it would make me a little nervous, so the more info the better.
    • soviet_merlin
      Duncan's V37.......race car?

      By soviet_merlin · Posted

      Thanks for doing that Duncan! Makes you a good person in my books. We don't get kangaroos or wombats here. But we have bats and it's similar. AFAIK it's often the mums with a baby attached that get hit because they drop lower when starting from a tree. If you hit an animal, check on it. https://www.ifaw.org/au/resources/wildlife-rescue-app An app to get the closest wildlife rescue contact.
    • Murray_Calavera
      Jacks that fit under GTR lips that can reach the subframe?

      By Murray_Calavera · Posted

      My dream is also to have a proper hoist, but I don't think it will ever happen. My quickjack is probably as close as I'll ever get, it really is very good though. 
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      Yeah we keep on in the dailies, it is pretty poor how many animals get hit and the driver leaves without checking....have saved a couple of little ones over the years. Bit of a gruesome job though, pouches generally need to be cut open because they are so tight and often the joey doesn't realise mum is gone so they are still locked onto the teat. I checked the modules in front of the DS wheel where an oil cooler should go.... There is the radar unit - that can go for race use) One of the 2 HX water pumps, the silver cylinder. That needs to be kept but might be able to be relocated But the bad news, the big computer mounted vertically in front of the wheel (blocking any potential air exit) is the electric steering computer. That is required until/unless i do a hydraulic steering conversion, and in CAD based modern car design it is not like I can just pop a big unit like that somewhere else (plus the loom would be too short anywhere else too). So, the passenger side is OK to clear out (just use a smaller washer reservoir, potentially elsewhere), but the DS no beuno
    • Duncan
      Chris' Toyota Mark ii JZX110

      By Duncan · Posted

      Well, all the best with the new camry It was interesting to hear about the UK process, it is generally a lot more streamlined here with a shipping agent looking after all the import side (noting the exact final price can still be a surprise.....) and I've used a few different brokers on the japan (or US) side, and never had any trouble with any of them....luck of the draw I guess. You mentioned you didn't get the auction sheet (understandable since you bought it from a dealer, not auction), but I always try and get hold of that because they are pretty thorough. I've imported 2x R grade vehicles over the years and both were fine, repairs in Japan are pretty thorough compared to here in Oz.
×
×
  • Create New...