Jump to content
SAU Community

Rough Idle When Ac Is Off

DNR33

By DNR33,
in Engines & Forced Induction

 Share

Recommended Posts

DNR33 Enthusiast

DNR33

Posted
Posted

I recently got a set of 500cc injectors, adjustable cam gear, and new spark plugs fitted to my S2 R33 GTST. Since they all went in my car is idoling really rough when it is at idol, But when i turn on the AC the car seems to idol perfectly. This only occurs when the engine has reached its normal running temp. On cold nights and initial start up it idols fine with the AC on or off.

Could this be due to a lazy tune or parts not fitted properly

Why would the AC make the car idol better.

If any one can help it would be great so i have some information before i go back and ask the shop.

Thanks Guys

DAN

Link to comment
https://www.sau.com.au/forums/topic/151777-rough-idle-when-ac-is-off/
Share on other sites
46n2 Mentor

46n2

Posted
Posted

i'm not sure if RB's have one but CA18's have a seperate solenoid which controls idle when the A/C is on. If there was a problem with this it might explain why there's only a problem when the A/C is on. Hope that helps...

DNR33 Enthusiast

DNR33

Posted
  • Author
Posted

Thanks for the info guys.

I do have a power FC.

I just wanted to get some ideas so that when i go back to my tuner I have some input incase he turns around and says its normal or something like that. Ill get him to check al the things mentioned.

Thanks Again

DAN

  • 1 month later...
grippy Collaborator

grippy

Posted
Posted

Sounds like you have FC disease! Try moving your AFM further away from the turbo inlet. You have upset the delicate nissan design/tune by running more boost, fuel etc.

Air is bouncing from the turbo inlet causing a pulse effect to the AFM and the ECU cannot compensate quickly of finely enough at idle.

When your A/C comes on the idle is increased enough that airflow is more stable across the AFM.

This is very common with mildly upgraded RB's.

Will always idle a little rough with 500cc injectors but can be minimised to be very slight.

Clean your aac valve and idle screw also, this may help. Cycle your idle screw full range of adjustment when cleaning also.

Rgds, Grippy

Devils_Advocate21 Mentor

Devils_Advocate21

Posted
Posted

Interesting topic which i have to follow, changing injectors this w/e as the tuner reconed injectors. then may have to check that afm thingy, as my does the same, and yes i have thouroghly cleaned the aac as well, noticed with mine the timing jumps with this aswell, and once either fan or ac is on it sits normal aswell, Injectors on this case are deatchwerks 550 cc, On another note could it be battery power?

180or200 Proficient

180or200

Posted
Posted

mine also burbles a little at idle, wouldnt say its a miss, and is smoother when the a/c is on! I have nismo 740's and they are trying to run at less than 1% at 900 rpm, i think its a load issue, and that my light frisby flywheel doesnt help!

grippy Collaborator

grippy

Posted
Posted
Interesting topic which i have to follow, changing injectors this w/e as the tuner reconed injectors. then may have to check that afm thingy, as my does the same, and yes i have thouroghly cleaned the aac as well, noticed with mine the timing jumps with this aswell, and once either fan or ac is on it sits normal aswell, Injectors on this case are deatchwerks 550 cc, On another note could it be battery power?

No it cannot be battery power. You car will run with the battery removed. Start it up and try it out, pull the battery leads off and she keeps humming.

Grippy.

grippy Collaborator

grippy

Posted
Posted

Doubt very much it would be the cam gear. Do any of you guys run after market blow off valves??

I had the same issue with my RB20 after upgrades. The big problem for me was the standard blow off valve was no longer venting back into the inlet pipe just before the turbo inlet. This was because I had a custom inlet pipe made. I had to remove the inlet pipe, have it modified so it could take a pipe from the blow off valve. It now still idles a little rough but only very slight. Before it was stalling and very rough.

The position of the AFM is also very critical to stop inlet pulse. I had to move mine further away also.

Grippy

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

    • Kapr
      Possible swap on R34 RB20DE NEO?

      By Kapr · Posted

      Hi. A little bit of an update. It maybe(hope not) looks like i would need a new tranny(it would be "maybe" a cheaper or better option anyway) So i need some info. I know i need a different propshaft(i can make custom one) LSD is not a problem cuz the engine will be still(for now) N/A RB20. So if i buy RB25DET NEO tranny...is there something else i need? I read something about push/pull type but i do not know if i need to "change" something or i can just plug n play onto my engine a go? Thanks for the advice  
    • OakvilleGTR
      Turn signal wiring question

      By OakvilleGTR · Posted

      Good morning all, Bit of a random question but figured I’d finally throw it out after wondering for a long while. Before I start, I'm hoping to do this purely out of personal preference. I think it would look better at night, and don't mind at all spending a few hours and dollars to get it done. I've copied this from a non-Skyline specific forum, so I apologize for the explanation of our headlight switch setup that we all know. Here we go: Zero lights (switch off) Parking lights (switch position 1) being a rectangular marker on the outside of the housing, my low beam being the projector in the centre (position 2), and a high beam triggered by my turn signal stalk. Most North American cars I’ve owned of this era have power to the amber corner (turning indicator) light as part of the first switch (parking lights). I’d love to have these amber corners receive power when the headlights and parking lights are on (headlight switch), yet still blink when using the turn signal which is of course a separate switch. Hopefully I’ve explained my question correctly. Is anyone aware of a way in which I might be able to achieve this? Thanks in advance
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      My heads are cathedral port! It's likely possible, but I don't want to add any extra moving parts (I know they don't move) between the heads, manifolds, etc. It will also affect how injectors/fuel rails etc sit and I don't really know if it would change how the FAST manifold goes/sits/fits. I have the LS6 steam pipes already as I have a very late LS1 block so it should be fine. I couldn't find anyone who had ever actually used one for this purpose, it seems 100% of people grind the water pump. The thermal spacers are 12mm and are half way to the cost of the newer water pump anyhow... so if it comes to that I suppose I'd rather buy a new pump. The bearing in the pump I do have is a little.. clunky, but it hasn't done that much time and I never noticed it when the car was together in the past few years, so..
    • sonicii
      Lower A arm Skyline v35

      By sonicii · Posted

      The bushing has failed, not all that uncommon for a car of this age.  Any mechanic should be able to push in a new bushing for you, or you can probably buy the entire lower control arm, complete with bushes.
    • The Bogan
      Mistakes were made, my R34 Story

      By The Bogan · Posted

      Could you not use "thermal" spacers to give the clearance, like the ones I used between the blower and head? That raised the manifold height by around 10-15mm Albeit the ones I used were for cathedral ports, but I assume they have similar for rectangular ports????
×
×
  • Create New...