Hi everyone --

I have the weird NZ/Middle East spec NA FC, the one with the S5 body, S4 engine, GSL-SE ignition system and no catalytic converter.

Less than 58k miles on it.

Most of the time, I run my FC on 96~97 RON fuel, but reading the forums and stuff, I thought about trying 86 RON.

The thing is, I noticed that when I am running on 86, there's a weird noise coming from.. somewhere? in the engine bay at WOT. You can hear it slightly (it isn't loud at all), it sounds like a strange whistling noise, maybe a bit rattling. This noise only shows up when I am in gear, and not in neutral.

Running 86 RON also means a lot of backfire, and less MPG.

While running on 96~97 RON, this weird sound just doesn't show up for some reason.

Any ideas on why this might happen?

What should I do? Should I use 86 RON or 96 RON?

Any information will be greatly appreciated.

 

Sounds like you may be running too much ignition advance. The "rattling" is a similar sound to pinging.

 

The thing is, my car is 100% stock... what could be leading to ignition advance on a completely stock car?

 

Check timing as per the Factory Service Manual. Maybe the dizzy has been bumped?

If its definitly a whistling, then check for vacuum leaks.

 

This is the service manual I have -- unfortunately it doesn't say anything about how to adjust the ignition timing on the non-Australian version of this type of FC...

What should I do?

 

Seems like you did some research since last time. I would check the FB manual since your FC uses the GSL-SE ignition.

 

As I recall, all you'll need to do is disconnect and plug the vacuum advance line, make sure the car is at idle speed, and adjust the dizzy until the timing mark lines up.

 

This is what the GSL-SE FSM says on ignition timing...

-- and I don't understand a thing

 

I took my FC out a couple of minutes ago and I noticed the following -- this whistling-rattling noise only shows up on WOT, and only from about 2000rpm to 4000rpm.

The moment I get past 3800~4000rpm, the noise simply disappears.

 

I think I am getting the same or similar noise in my GTU. I hear what seems to be a hissing noise when I go above 5k and it stays there until I let of the gas. I only hear it sometimes. It seems to be coming from behind the gauges. I am not loosing any fluids and it doesnt seem to have an adverse effect on performance. I dont think it has any connection to speed. Any ideas?

 

I had a whistle a BAD one! started out small and got louder and louder... it was my EGR .... I found out that if I put some aluminum foil or heat resistant tape pushing the one side down it stopped it temp. of course by no means a suggested perm fix!

Sounds can play tricks on you because of echo etc.... it took me almost two hours and a set of ear plugs... yep ear plugs helped me be able to put up with the sound longer and also get a little bit more specific on where the noise was coming from.

Good Luck

 

Take the car to a mechanic.

If it really is a loud whistle, then it's going to be something like a vacuum leak. You'll have to check the FSM to determine what solenoids are active around that RPM range.

 

I will!

Here's a video in which you can hear the whistling-rattling noise a bit --

http://www.youtube.com/watch?v=HHyNWYNfU2Y

It shows up on 0:08, til 0:12 aproximately.

It's obviously louder, I was just holding my camera by it's strap with my teeth, while driving with the driver's window down.

 

Sounds a bit like shifter rattle, or just something loose (exhaust heat shield?).

 

The weird thing is... this sound only shows up when I run on 86 RON fuel.

I also just noticed that I am running BUR9EQ sparkplugs... while I should be using BR10ETs...

 

Running on BUR9EQ's instead of BR10ET's may be related to this?