Jump to content
SAU Community

Revs Fluctuates Up And Down At Idol, Also Misfires

Duff_man

By Duff_man,
in General Maintenance

 Share

Recommended Posts

Duff_man Collaborator

Duff_man

Posted
Posted

hey,

I have a 93 r32 skyline and ever since i have bought the car about a month ago when i am sitting at idol the Revs fluctuate up and down around 100 -300 revs, also misfires occasionally

i have only really noticed this when its just sitting and idol and will get worse if i leave the car to idol for long periods

it does not do this when the engine is cold and the choke is on, it really only happens when the car is warm/hot

i have recently replaced the air flow meter, oxygen sensor and had the TPS (Throttle position sensor) adjusted

If anyone knows of wat could be making my car do this or have any suggestions don't hesitate to Post

cheers

Benzino33 Experienced

Benzino33

Posted
Posted
is that like the iacv valve?, would the fix the misfire as well?

Yes the Iac valve will fix ur hunting idle..the misfire would be a coil pack issue

Benzino33 Experienced

Benzino33

Posted
Posted
ok. yeah but if the misfire was a coil pack, it would continue as i rev up the engine wouldnt it?

Yes it does both, my car used to misfire at idle like mofo, and up above 500rpms, after i changed the spark plugs to platinums and changed the coils, it ran beautifully..But if u gonna change the coil packs,have the taped up or covered in silicon gel so no spark escapes from little hair line cracks. Either that or get splitfire coils and u wont regret it

chrrrz

Ben

Parag0n Mentor

Parag0n

Posted
Posted

Are you running an aftermarket ECU? I had idle hunting problems running power FC base maps on numerous RB engines.

Otherwise I would be cleaning out your ICU and changing sparks, check the coils and leads too see how they look as well.

Duff_man Collaborator

Duff_man

Posted
  • Author
Posted

nah standard ecu. cheers, yeah i'm thinkin it could be the leads to coil packs, i have read other people's posts with similar problems and they were talking about CAS, wat is CAS? and if it is this how can i check

Benzino33 Experienced

Benzino33

Posted
Posted
Are you running an aftermarket ECU? I had idle hunting problems running power FC base maps on numerous RB engines.

Otherwise I would be cleaning out your ICU and changing sparks, check the coils and leads too see how they look as well.

Yeah,,check the ignition leads and look for a vacuum leak too,,might just be that

nIsMo86 Experienced

nIsMo86

Posted
Posted

CAS = Crank Angle Sensor...Its silver and sits on the front of the motor on the exhaust cam.

ICU is not the name...Its AAC valve = Auxilary Air Control Valve. It is located at the rear of the plenum and looks like an alloy block with a small can on it. Has connector plugged into it.

I'd suggest you clean out your AAC valve first and go from there. Theres a guide on how to do it on here somewhere. Have a search and you will find it.

  • 3 weeks later...
cattivo_69 Community Regular

cattivo_69

Posted
Posted
CAS = Crank Angle Sensor...Its silver and sits on the front of the motor on the exhaust cam.

ICU is not the name...Its AAC valve = Auxilary Air Control Valve. It is located at the rear of the plenum and looks like an alloy block with a small can on it. Has connector plugged into it.

I'd suggest you clean out your AAC valve first and go from there. Theres a guide on how to do it on here somewhere. Have a search and you will find it.

if u disconnect the plug on the AAC wat will happen to the car while its running? my idle is all over the place, and when i clutch in too quick at the lights it stalls

other problem is the car is running way too rich.. the back bumper is always black??

wat to do?

PUDZ 32R Enthusiast

PUDZ 32R

Posted
Posted

the AAC valve only controls the engine idle when you turn the air con etc on and the IAC or idle air control valve does the idle if i am not mistaken?

clean them out and check for vac leaks even a tiny hole in your intercooler can screw the AFR and this will make it run heaps rich and idle like a bitch.

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

    • MBS206
      R33 Fuel Pump & Brakes after alarm swap

      By MBS206 · Posted

      Who did you have do the installation? I actually know someone who is VERY familiar with the AVS gear. The main point of contact though would be your installer.   Where are you based in NZ?
    • GTSBoy
      R33 Fuel Pump & Brakes after alarm swap

      By GTSBoy · Posted

      Look, realistically, those are some fairly chunky connectors and wires so it is a reasonably fair bet that that loom was involved in the redirection of the fuel pump and/or ECU/ignition power for the immobiliser. It's also fair to be that the new immobiliser is essentially the same thing as the old one, and so it probably needs the same stuff done to make it do what it has to do. Given that you are talking about a car that no-one else here is familiar with (I mean your exact car) and an alarm that I've never heard of before and so probably not many others are familiar with, and that some wire monkey has been messing with it out of our sight, it seems reasonable that the wire monkey should be fixing this.
    • GTSBoy
      After market rear camber arm adjustment

      By GTSBoy · Posted

      Wheel alignment immediately. Not "when I get around to it". And further to what Duncan said - you cannot just put camber arms on and shorten them. You will introduce bump steer far in excess of what the car had with stock arms. You need adjustable tension arms and they need to be shortened also. The simplest approach is to shorten them the same % as the stock ones. This will not be correct or optimal, but it will be better than any other guess. The correct way to set the lengths of both arms is to use a properly built/set up bump steer gauge and trial and error the adjustments until you hit the camber you need and want and have minimum bump steer in the range of motion that the wheel is expected to travel. And what Duncan said about toe is also very true. And you cannot change the camber arm without also affecting toe. So when you have adjustable arms on the back of a Skyline, the car either needs to go to a talented wheel aligner (not your local tyre shop dropout), or you need to be able to do this stuff yourself at home. Guess which approach I have taken? I have built my own gear for camber, toe and bump steer measurement and I do all this on the flattest bit of concrete I have, with some shims under the tyres on one side to level the car.
    • Jarsky
      R33 Fuel Pump & Brakes after alarm swap

      By Jarsky · Posted

      Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
×
×
  • Create New...