High Idle

[LotusGTR]

I have an R32 GTR that idles high. This is somewhat controlled user the Power FC but it still settles at 1200-1300rpm = very annoying. This is with the idle adjust screw at full adjustment. The issue (I'm told by my engine builder) as that the throttle blades are worn (the telfon or coating of the blades) and they need to be re-coated. I currently have the engine out for other reasons and want to get this fixed up if possible. Trouble is that the throttle assembly looks like it was not made for dis-assembly (there is apparently some crimping in the assembly) and therefore we're looking at getting new from Nissan which is ex Japan and anywhere from $1,000 - $1,600 for the part depending on which part # you beleive (this is being resolved overnight). This is too much time and $$ so wondering if anyone could make a suggestion as to how to handle this? Are there other ways to approach solving this problem? I seem to remember someone suggesting you could spray some sort of rubber to the underside of the thrittle blades and allow it to go off a little and then open the blades so they don't stick, until it goes off completely and then........it doesn't sounds right to me but just provoking thought. Wrecker parts?

Any help would be appreciated from those who know reliably how this could be handled.

Thanks in advance.

[Bozz]

I adjusted the three factory stops, the ones the manual tells you not to touch, that brought my idle back down.

Perhaps find the cost of a secondhand throttle body from a newish model GTR from the wreckers?

[LotusGTR]

I adjusted the three factory stops, the ones the manual tells you not to touch, that brought my idle back down.

Perhaps find the cost of a secondhand throttle body from a newish model GTR from the wreckers?

Those stops actually in the throttles themselves? Thanks.

[gtr fan]

I am sure you can rebuild the throttle bodies.

I have the same issue and have been quoted around $1,000 to rebuild and adjust.

Their is even a tutorial on here about doing it.

I am sure these are not a disposable item.

[paulR32gtr]

Sounds feasible that the throttles are the cause.

One other cause I have heard of - has the paint been stripped off the plenum at some point? If so how was it done - blasting per chance?

[LotusGTR]

Sounds feasible that the throttles are the cause.

One other cause I have heard of - has the paint been stripped off the plenum at some point? If so how was it done - blasting per chance?

Hi Paul, that is possible as the plenum is nice ans shiney, but not done by me. The car was (and is) in pristine condition so it's possible it's the original paint too? If it was re-painted, what's the follow on thinking?

[paulR32gtr]

Hi Paul, that is possible as the plenum is nice ans shiney, but not done by me. The car was (and is) in pristine condition so it's possible it's the original paint too? If it was re-painted, what's the follow on thinking?

Ok sounds an unlikely cause then.

I have been told that sand blasting *could* lead to the plenum becoming slightly pourous, resulting in a high idle.

[gtr fan]

http://www.skylinesaustralia.com/forums/topic/286728-nissan-gtr-high-idle-and-throttle-body-fix/

This is it.

Let us know how you go.

Another issue maybe that one of the throttle body blades couldbe slightly bent.

Just recently happened to someone here. In this case a replacement throttle body assembly was required as you are unable to just replace a blade.

Edited September 6, 2011 by gtr fan

[LotusGTR]

Thanks guys. I've done a fair bit of research and have spoken to the workshop and we've agreed that for all the mucking around and uncertainty around fixing the issue we'll either find a suitable wrecker part or go new from Nissan. New could be as 'low' as $1,100 and as high at $1,600 so not great - in fact terrible. Wreckers are selling them for $250 (ah, much better) but of course they may have similar problems. The wrecker in question is close to my workshop and will drop in with 3 throttle assemblies so they can be inspected. Hopefully 1 fits the bill as this carries least financial and time penalty.

Will let you know. FYI I've specifically asked the workshop to confirm they have problem solved the following items and the answer was yes and they're 99% sure it's the baldes sealing against the body that's the issue. Likely there was an issue originally, but was masked by the build up of carbon, but when my engine was rebuilt the throttles were cleaned and the full extent of the problem was revealed. Their feedback is that this isn't uncommon. Hope this helps with future searches.

Air Regulator

Auxiliary Air Control Valve

Throttle position sensor

Temperature Sensor

Throttle Plates mechanical stops

Throttle Valves Positioning Sensor

Ignition Advance

Vacuum leaks in Hoses

Collector / Inlet Manifold Gaskets

[Beer Baron]

tomei make a coating for the throttles bodies that helps the butterfly seal against the throat.

scroll to the bottom of this page:

http://www.tomei-p.co.jp/_2003web-catalogue/e193_others_gauge.html

[Beer Baron]

I have been told that sand blasting *could* lead to the plenum becoming slightly pourous, resulting in a high idle.

all I can say is lol! sand blasting plenum leaving it porous to the point that it's sucking in air through the casting? it's pretty unlikely. castings can have pin holes in them but they don't just appear after a light blasting to remove paint. it will have to be so porous you could just about see through it!

[paulR32gtr]

all I can say is lol! sand blasting plenum leaving it porous to the point that it's sucking in air through the casting? it's pretty unlikely. castings can have pin holes in them but they don't just appear after a light blasting to remove paint. it will have to be so porous you could just about see through it!

Yes I thought it sounded a bit far fetched. But its from a trusted source that actually sand blasted several of the plenums and all the cars ended up with high idles, since then only paint strip them and no more problems. It may just be a coincidence... and maybe the throttles were having the sealant removed as well... but just something I had heard was interested to see if his plenum was stripped.

[LotusGTR]

OK, so I spoke with a very helpful fella called Steve from EFI Hardware in Mitcham 03 9873 5400. He says there is a Loc-tite moly dry film lubricant (part # 39895) spray can that goes for about $90. You open the throttle blades, spray the bores, let them air dry (say 30 mins), let the throttle close on its spring (in doing this it scrapes some of the semi set materials into a ‘seat’ for the blade to close on to). You then bake the whole lot in an oven at 260 degrees c for 30 mins and it becomes hard and solvent resistant. The oven kills the 'side seals' which will then need replacing. EFI have them and say they are hard to get as they are metric. Forgot to get a price. Says he’s done this fix before and it worked. Also said a cheap and short term fix is to take off the plenum and spray this stuff onto the throttles, but because the goo is not cured with heat it eventually fails.

I'll update the thread once this is sorted one way or another.

[Beer Baron]

same principle as the tomei stuff. plenty of people have used/use the tomei stuff but this other process sounds fine too.

[XRATED]

Shaft seals are $120 last time I bought them.

.. day job on the bench to replace them.