[jensen2000]

After a 9/10 month rebuild following complete bottom end failure my GT-R33 V-Spec is alive again. Now at a bit of an en-passe; MOT required but engine not run in so emissions due to un-run-in engine dire and way over.

However, more of an immediately pressing nature is the 12-1600 rpm hunt/surge which repeats every second rhythmically/consistently. The cold-cycle idle is solid and clean, but once out of closed loop...Due to my 1000cc injectors you can hear clearly the brain trying to work it out. Essentially the tick of the injectors taps out the increase in revs then they cut "silence..." and the revs drop to 1.2k before the cycle picks up again tick...tick...tick... 1.6k" etc...etc..and so on.

Picks up clean on the throttle.

Trouble is the MOT analyser cannot get any reading because this is way above the range expected.

I've narrowed it to.

1) Idle air controller
2) Vacuum leak
3) Intake leak
4) AFM

Is this a reasonable assessment?

Smoke testing intake side to check for leaks. Same with vacuum. Cleaning of AFMs/ AIC...Most likely cause of this out of the options...?

Cheers
J2K

 

[DazGTR]

I had this on my last gtr had intake gaskets replaced but never completely cured it,had new afm same probs, plugs,fuel filter but to no avail i put it down to the fact that it musnt have been mapped for uk fuel, but defo dont rule out the following:-
1)fuel filter
2)correct plugs(heat range)
3)leaking injector seals

P.S easiest way to check for intake leak is to spray carb/brake cleaner on the gaskets and if the revs speed up youve got a leak only reason i know is cos rod at RB did this on mine.

 

[jensen2000]

Idle Air Controller...

Is the Idle Air controller essential? We've now discovered mine is disconnected competely. In fact the plug is missing from my loom altogether.

Confused as to how idle can be controlled...

Any thoughts?

Cheers
Jen

 

[DazGTR]

I have read that some folk have bypassed it but that was only to test if it was faulty but never heard of it without one.. are you sure its not there? the plug should be a brown coloured one, it may just be tucked out the way

 

[jensen2000]

Cheers Daz. Without the iac presumably there's no way to compensate for differing loads I.e. Air con etc. It would be my mech that's failed to spot it then! That would be a worrying state of affairs but the connector must be there. I hope "gulp"! Cheers again Daz.
Jen