R32 Gtr Running Rich, Suspect Vacuum Leak, Any Thoughts!

[Gorilla26]

Hi guys, I have a 32 GTR with a few mods, nistune, 34 afms, unsure on turbos (only just got the car), built motor, 34 crank, camtec cams, etc etc,

The car is running very rich and stalls when I come up to a set of traffic lights, it is running standard bovs, would a vacuum leak cause this to happen? What is generally the cause of a vac leak in an RB26? Are there any common hoses that deteriorate quicker than others?

Thanks!!!

[Ben C34]

Vac leak would make it run lean when off boost if the leak is in the inlet manifold . rich if its a boost leak in a cooler pipe.

Did it always do it@

You should really take it somewhere and run it on a Dyno to check it out.

[Gorilla26]

I just got the car so I have a few little issues to sort out, also need a power steering pump.... Hicas has been removed if that changes anything...

[Trex]

a big enough vac leak would cause stalling when you let off the throttle.

[Gorilla26]

Yeah, that's what I thought, where are common leak areas on rb26s?

[Missileman]

broken O2 sensors will make run rich too

[breaker1845]

You have the stock bov's but are they actually functioning correctly and plumbed back? If they aren't that is probably your issue.

Run it on the dyno or do a smoke test to find your leaks after checking the BOVs. It could be poorly tuned also contributing with the leak resulting in the car stalling.

[Gorilla26]

Thanks for the help guys, the car previously made 400rwkw then has been put into storage for a while and there are now a few issues to sort out. What vac lines are under the plenum that could have perished or might be leaking???

[Gorilla26]

How do I do a smoke

test?

[Hadouken]

google it

[Duncan]

well a smoke test is the best way to get to find a vacuum leak, but it requires specialist equipment. Easiest thing to do is to give it to someone who does this all the time unless you are familiar, there are billions of pipes and they won't be standard on your setup

As far as finding it yourself, I'd start with the main intercooler pipes in the engine bay and under the front bar, they are by far the most likely. They check the BOV return lines wherever they plumb back in. Then the boost controller lines and their attachment to the wastegate. Then however your AAC is linked up, that should cover most of the vacuum lines.

[Gorilla26]

Thanks mate, I'll have a good check over everything,

[blind_elk]

Its got aftermarket cams and a Nistune - shouldn't that be the first thing to be looking at. (after cleaning the AAC valve)

[Gorilla26]

What is AAC valve?

[Hadouken]

You need to learn the Google.

It's the device that basically controls your idle at all times.

http://www.sau.com.au/forums/topic/110431-diy-aac-valve-cleaning-idle-reset/

[Gorilla26]

Oh, just looked it up, are they the kind of thing that needs a periodic clean?

[Gorilla26]

I have learned the Google

[breaker1845]

If you don't know what it is don't touch it? Got a workshop around that is experienced with Skylines that can help you out? Smoke test and getting the vehicle on a hoist will help significantly.

I'd still put money on it being the BOVs or a combination of BOVs being not plumbed back, broken and the ECU tune being rich to begin with.

[Hadouken]

Or just follow the diy and give it a quick clean. They only need cleaning every now and then. They do well