8 replies to this topic

[Seb.F]

Right, so I did my first track day as S/C on sunday at rockingham, had a couple other issues show their head, but they are known and easily solvable. This one however isn't... not in my head anyway. Since sunday, the engine won't idle as it usually did. It normally warmed up and settling to about 800-900ish. Now it just sits dead on 1k pretty much whether it's hot or cold. Not only that, but when I stop and let it idle, it will vary between 1000 and 1250 rpm, seems completely random. Now normally on cold start ups, it used to sometimes stutter a bit when on half throttle between 2 and 3k rpm as if it was just on the verge of boosting but not quite, it went away when it was hot. But now, it doesn't do it at all, but in its place, there is the usual supercharger whine, at 1000rpm..... :/ I'm pretty sure that's not normal, and it does it a LOT more in 4th or 5th gear, say I'm cruising in traffic and I slowly pull away in 5th, the whine picks up instantly, louder the more throttle I use, it starts higher pitched then lowers and goes away at about 3k, then you can start to hear the usual familiar whine coming in. I've checked the servo hose, and it was fine, and the fuel pressure regulator was as well. Changed the actuator/solenoid for a brand new one I had lying around, and removed fusse 8 of the ECU for 5 minutes, none of it made any difference at all. It still starts up and idles all over the place. Has anyone got any idea, as this is my daily car and whatever it is I'd rather fix, that it leave me stranded at the side of the road with a larger repair bill. Thanks Seb

[chris_uk]

did you get it mapped propperly at courtenays? of are you still using their base map?

[Phear]

My best guess is you've got an air leak post throttle. Possibly: Brake Vacuum Hose split. Fuel Tank Vent Hose split. Bung in the SCIP hole in the top of the charger not sealed. MAP Sensor not sealing properly. SC->Inlet Gasket air leak. Inlet->Head Gasket air leak. Air leaking past the throttle can cause higher idle and can cause it to wander as the the ECU tries to compensate by adjusting the throttle. The whine could be air leaking in through a small hole somewhere.

[Seb.F]

did you get it mapped propperly at courtenays? of are you still using their base map?

Its got a stage 2 map on it mate. Was fine before sunday though. I think an air leak is what it may be phil yeah. Need to get some time to check it out.

[Arno]

But now, it doesn't do it at all, but in its place, there is the usual supercharger whine, at 1000rpm..... :/ I'm pretty sure that's not normal,

That's not normal. Sounds like your S/C bypass valve is no longer opening and stoppng the S/C from boosting at idle and cruise/low throttle rpm's. An 'engaged' S/C at idle tends to give odd idling issues because of the positive pressure.

Check the vacuum hose that connects the intake manifold to the actuator that operates the valve/flap in the S/C housing. Perhaps the hose got loose, the actuator is stuck or the valve is not working anymore.

Bye, Arno.

[Seb.F]

Thing is I've replaced the whole actuator and hose for a new one Must be some sort of air leak, Jon has said that I should spray some carb cleaner around the S/C and see what happens...

[simsy]

Is the engine software specific for the SC, or NA stage 2?

[Mike (Cliffie)]

This is not a map issue, it is an air leak issue. My best guess is the SC to Manifold gasket or the SC has worked loose and is being pulled down by your short belt. Hopefully you will be able to tighten it all up once you have released the tension on the belt, worse case, you need a new gasket. Buy a longer belt Seb!

[Seb.F]

Longer belt should be here tomorrow, let's see how it goes!!