Idle Question

[deano27]

Hi Guys,

My r34 GTT when cold idles a little rough. Not very bad, but every few seconds it seems to miss.

When the car warms up it doesn't seem to do it anymore. 

I have also noticed the cars sort of misses when backing off the throttle while driving.

The car is stock other than full exhaust, pod filter and HKS BOV.

Anyone experienced this?

Cheers,

Dean

[Jdfnq]

is the blow-off valved plumbed back???

If not, this could be an issue

[Kujotk]

when you back off and you say it "misses" how do you figure that out? most of them back fire.... also when cars warming up and the normal idle revs are high, it may flutter alittle because i read on the forums here somewhere that its electronically alterd to rev at about 1500rpm when cold and then it brings its way down to normal idle (should be about 700ishrpm).

My idle used to jump around alittle and would sometimes stall at round abouts (very rarely). I cleaned the AFM, changed spark plugs and cleaned the throttle boddy. That got rid of most of the problems but i still noticed it wasn't a constant idle and would sometimes seem to miss. I didnt worry about it coz it didnt stall anymore.

Then i changed the 02 sensor and immediately found that the idle prob was gone completely, just by chance, now i also save about $15 in fuel/ week by putting a new (EL Falcon) 02 sensor for $70.

dont know if it would work for you but it did for me, so i figured for my car anyway that the idle changes were something to do with the car switching from running lean to rich because of the faulty original 02 sensor.

They shoul;d be changed every 40000km nissan recons, if you are getting anything less than 400km/taknk with reasonable driving conditions i would definately get new 02 sensor, i get 450km/tank with pod, turbo back, 10psi boost, fmic with the new 02 sensor, where as before i'd get between 250-350km/tank

[Kujotk]

is the blow-off valved plumbed back???

If not, this could be an issue

+1 for this aswell, this can be similar situation, i was told it could be my blow off, found out it wasn't for me anyway

[deano27]

no it's not plumbed back and i think the backfiring did seem to start after I installed the BOV.

The idle on cold is a little weird though. It's not when it's reaving high, it's when the revs drop to about 900 before the car is warm and then drops to about 700 and idles fine.

My fuel economy is quite good, i get about 500-550 km per tank.

Maybe I will look into changing the o2 sensor. I did notice though after last night when I installed my air fuel ratio gauge that it keeps jumping from lean to rich all the time. Don't know if it's a faulty connection. When I am accelerating it seems ok though.

[QWK32]

its supposed to jump from lean to rich when your at idle or light load, if you put a good multimeter on the signal line it will continuously jump from 0.1v to 0.9v to 0.1v really fast.