Rough idle after fitting HKS filter

[MentalDev]

Quick question, just fitted a HKS filter and the idle has gone to crap, as soon as you back off the throttle it dies down to 500 or less rpm and semi stalls, the TCL OFF comes on as does the battery light.

I disconnected the battery while I fitted the filter so is this just the ECU INSERT INTO post VALUES (standard) learning and it will sort itself out after a day or so or something else..? I've only done a couple of km's since fitting it.

On the plus side getting higher boost, or more like high boost quicker

Cheers, Jason

[BraindG]

mine has done this a few times aswell.. had filter fitted since december, but every now and again, it will drop below 500 and it feels like its going to stall, then picks back up again..

but intially, after fitting it, i didnt have this problem..

currently my filters a mess, it needs to be replaced.. but im assuming yours is brand new..

see how it goes after a few more miles, or KM's in your case.. before getting to worried about it..

[pjjohnson]

I had a similar problem - it turned out that there was an air leak into the system.

[Spirit]

Mine has been perfect since day 1 mate so I would check to ensure no air leaks as PJ said and that all your jubilee clips are tight then take it for a decent burn to give it chance to settle down with the ECU.

Pete

[Brind]

Never had a problem either.

As has already been said, check for leaks and ensure the filter is seated correctly.

It could be wise to disconnect the battery again and leave it off for a while, I don't know for sure how long it takes to reset the ECU but if you don't need the car for a while just disconnect it and reconnect it later.
Start the car and leave idling for a while without revving, I've read people saying they've left their cars ideling for about 20 minutes but I doubt it would take that long, but leave it running for a while anyway and then give it a try, pehaps stopping the engine and then starting before driving.. just in case that makes a difference.

You'd be surprised how funny these cars are, my car was being used on normal unleaded fuel before and just after I got it, I had an AYC fault so took it to the dealer to be checked, the ECU was reset and it was then that I found I had a huge amount more power than before!!
Apparently if the car runs on crap fuel or possibly in my case lower octane fuel the ECU goes into shutdown and consequently the car runs on lower boost to protect itself.
I've read it could lose about 40-50bhp because of that.

[haydar]

Originally posted by BraindG
mine has done this a few times aswell.. had filter fitted since december, but every now and again, it will drop below 500 and it feels like its going to stall, then picks back up again..

but intially, after fitting it, i didnt have this problem..

currently my filters a mess, it needs to be replaced.. but im assuming yours is brand new..

see how it goes after a few more miles, or KM's in your case.. before getting to worried about it..

Mine's done this as well, before and after fitting the air filter. I'm not sure if it's really got anything to do with the filter or an air leak! If it was an air leak, wouldn't it do it all the time? The air intake should improve the air flow and hence improve idling???? PJ, did your car do it all the time, what other symtons were there?

Mine on average does it about once every 6 months so I'm assuming it's just an ECU glitch. Either that or it could be that it's just bad fuel or something? I've been told that the idle can be reset at a Mitsi dealer, but not sure?

[MentalDev]

Thanks for all your replies, yes she's sweet now, just needed running in, dropped in at my mechanics last night for a chat and he said it was just the ECU sorting itself out, when he does something like this, e.g. filter or exhaust change, he'll take the car for a quick drive for say 10Km to bed it back in and so the customer doesn't come straight back asking why the idle is rough...

Thanks again guys!

Cheers, Jason

[Spirit]

Another happy customer - just what we like