2.4 (4G64) GDI - Idle Problems

[ryanjames.powell]

Reset the ECU, start up the car when it's cold and let it run with the air con on for 10-15 minutes. Restart it if it stalls, and see if that helps.

Yep, that's basically how my mechanic does it. He knows a reasonable amount about these cars. I'm leaning towards a faulty sensor of some kind or something wrong with the ECU, but the ECU is apparently completely free of corrosion, so doesn't LOOK like it has a fault.

Any ideas what sensors might cause this?

[PRLWHT]

GDI engines naturally idle between 500 and 800 and that makes them feel like they shake. if it is constant at 500 and the idle is not varying, i wouldnt be too worried. it is how the cars run

[ryanjames.powell]

GDI engines naturally idle between 500 and 800 and that makes them feel like they shake. if it is constant at 500 and the idle is not varying, i wouldnt be too worried. it is how the cars run

Hmm, it says 650rpm under the bonnet, and there is a "notch" on the tacho at about there, which indicates to me that that is where it should idle. I know there's not too much difference between 500 and 650 but if you touch the accelerator and get it up to 650, it is suddenly silky smooth...

Anyway, I have more to worry about now. A day after I got it back from the mechanic, it started making a whirring vibrating noise, which I thought was the cambelt not being tight enough, and so did the mechanic. So he arranged to have it trucked back from Hamilton (an hour away - these things never happen at home ), and it turns out to be the bottom pulley on the alternator? or power steering? belt - the rubber has fallen out. This same thing happened about a year ago but I didn't notice as soon that time and it wrecked the cambelt cover (thankfully not the cambelt itself). So for the week I am a Subaru driver (shudder), as he has lent me his wife's WRX.

[PRLWHT]

yea i know what u mean about the idle, like i said, i have the same prob.

blimey, sounds like one thing after the other! hope you get it sorted and back on the road soon!

[ryanjames.powell]

Yeah, after this I'm thinking it's going to last quite a while. Everything should be in near perfect condition. No more oil usage, no more smoke, should be better fuel economy now that the exhaust manifold actually has airflow. Just annoys me a bit that I only had that same pulley replaced a year or so ago (although it was replaced with a second hand one).

I'm almost tempted to try Brad's suggestion of making a hole in the butterfly valve (since I actually have a spare throttle body which cost me $250 and nobody seems to want to take off my hands for any price). What's everyone else's opinion on this? Will it upset other things?

[bradc]

Just to reiterate I have no idea if this will work or not!

[ryanjames.powell]

Just to reiterate I have no idea if this will work or not!

Yeah, that's kind of why I asked for other opinions lol. It won't matter anyway, if it doesn't I can just swap it for the un-drilled one. My mechanic seems to think it can't do any harm (ie shouldn't have a bad effect on anything else). I think I will try it this weekend. I'll let you guys know how it goes.

[Rambaud]

And does not 98 RON petrol burn "cleaner" than 95 RON?

I have always used Shell V-Power/Tesco 99/BP Ulimate to minimise carbon build-up in my GDI.

I was aware that the higher ethanol blended petrol (10% and over) should not be used in a GDI engine - Tesco 99 is a 5% ethanol blend. However, according to Mitsi, ANY ethanol blend is unsuitable.

Fortunately, I have not found any Tesco selling its 99 RON fuel in Northern Ireland.

[ryanjames.powell]

Highest we have here is BP Ultimate at 98RON. Recommended is 100+RON. Sulfur levels are also an issue - Japan has about 10-15ppm, our BP Ultimate has about 20ppm, so it's not too bad of a fuel for the GDIs. Some of the regular (91RON) fuel I have heard is more in the region of 100ppm, which will cause severe loss of fuel economy and a rise in emissions.

[PRLWHT]

let me know how the hole in the butterfly goes, if it works ill try it myself. how much has it cost to get the oil to stop burning through?

[ryanjames.powell]

let me know how the hole in the butterfly goes, if it works ill try it myself. how much has it cost to get the oil to stop burning through?

Yeah, will post the results of my experiment in hopefully a few days. I haven't actually got the bill yet, will be paying tomorrow, but it was estimated to be about $1500-$2000. So not too bad really considering just how unhealthy it was. I'll let you guys know how much when I get the bill.

[ryanjames.powell]

OK I'm all paid up now. It cost me $1248.01 including GST for the following:

Remove all manifolds, disassemble cambelt, remove injector housing, dismantle and remove head, remove all valves, put all parts through cleaning machine, de-carbon head, clean all valves, lap all valves, fit new valve stem seals, re-assemble head, re-fit head and manifolds, fit new cam belt and adjust, re-fit covers, add new antifreeze and a full service including new oil and filter and topping up ATF/Diff oil where necessary.

So not a bad price at all...

BUT THEN I drove to Hamilton and the centre of the bottom crank pulley came out, so it had to be towed back to Waihi and have a new pulley fitted at a total cost of $814.93 including GST... Sigh. And I only had that same pulley replaced for the same reason in February of last year.

[ryanjames.powell]

Well, my experiment with the hole in the butterfly valve is over - I am pretty sure my spare throttle body is faulty. I got the check engine light a couple of times along with funny noises coming from the throttle body, and total lack of throttle response. So I'm giving up - I don't want to mess around with my good throttle body.

[Rambaud]

For a warmed-up engine, my idle speed is ~ 800 rpm in Neutral or Park.

[ryanjames.powell]

For a warmed-up engine, my idle speed is ~ 800 rpm in Neutral or Park.

Lucky...

I actually read the workshop manual for it last night and the specification is 650+-100RPM, so technically it is performing to specification...