ScoobyDoo69

iTrader: (17)

Bit of help here please guys.

Car: 03 STi
Mods - Full 3" exhaust, ported headers, stainless uppipe, RCM Induction kit, Remap on 20% meths. Blocked off DV.

The most recent work it's had done to to it was an APi uprated oil pump, but that was some months back and the car was fine pre and post to that running all the above listed mods for some time now. This has only started happening this week.

It is stalling when coming to a stop, unless I rev it to stop it dying. It is more evident when coming off a dual carriage way and stopping for a roundabout, but still occasionally happens with normal town driving..

Oil pressure etc is all registering fine on the Defi's when driving along normally, but as soon as you come to a stop, the Oil Pressure Defi slowly drops down and then as the car is about to stall beeps and shows about 1.5bar pressure before the car stalls.

So I presume it's not anything to do with the oil system, but my Defi's are warning me that the car is about to stall. Useful for something then..

Other symptoms include the car being quite back firey (more so than usual) and generally feeling a bit lazy on part throttle. Under full throttle it still seems to go as it should.

My guess would be that a pipe or similar has come off somewhere or something? Any other suggestions?

Thanks

Scooby Dan

Have you got a cold air feed to the induction kit ? I have the same kit on my Hawkeye and when I fitted a cold air feed it did exactly what yours is doing . I blocked off the air feed by refitting the fog light cover and it has been fine ever since . The extra air flow was causing turbulence around the maf .

ScoobyDoo69

iTrader: (17)

It does yes, but the cold air feed problems disappeared as soon as it was mapped. Like I say nothing has changed for a very long time, so I'm wondering if something has come off that I need to look for?

Plus isn't air turbulence mainly a problem at high speeds rather than coming to a stop speeds? I can't see why my cold air feed would suddenly be causing ill effect now?

KAS35RSTI

iTrader: (73)

I would try cleaning the MAF. Other things to look at would be cam position sensor & crank sensor.

chrisdicko

iTrader: (21)

Idle Control Valve a bit sticky?

ScoobyDoo69

iTrader: (17)

Cheers. I know where the crank shaft sensor is, and can unplug it etc, but the cam sensor? Also how do I clean the MAF, is there something I spray it with and then leave to dry?

I did consider the idle control valve, but surely that would affect idle all the time and not just when coming to a stop?

KAS35RSTI

iTrader: (73)

Get some brake cleaner & carefully just spray onto if from a distance & leave it to dry for 10-15min. Cam sensor is located behind right hand side of the cam casing held on by a 10mm nut i think, near the oil cap area. It has a connector which you need to disconnect. You can test it with a tester or clean it with electrol cleaner.

Worth a try. These things are soo annoying!!! It can be numerous things. You getting any CEL etc?

B0DSKI

iTrader: (17)

Mine used to do the same with the cold air feed from that foglight cover. Since I've switched to a blow through MAF it's been fine. I was told by Mocom that too much airflow can upset the MAF when in it's usual position and used with the cold air feed

ScoobyDoo69

iTrader: (17)

cheers Kas. I shall give those a go!

B0DSKI as much as I appreciate that fact, I have not had any issues with it for well over a year, when it was remapped. It has been perfect, and the cold air feed hasn't changed. So why would it suddenly be a problem if that was the case?

EngineMapper @ Group B Motorsport

Just randomly have you had the battery off or reset the ecu at anytime recently?

Sounds a lot like you have an air leak somewhere to be honest.

Graham

farmermo

checking all intake pipes for splits could be worthwhile too

KAS35RSTI

iTrader: (73)

No worries. Let us know how you get on.

ScoobyDoo69

iTrader: (17)

No resets or battery off. But if the ECU had reset, after all the miles I've done to see if it would sort itself wouldn't it have relearned and acted normal again?

I appreciate all the advise guys, thanks a lot, hoping to look at it before the weekend. So will let you all know how I get on. I suspect that it's a pipe somewhere, hopefully nothing major

APIDavid

iTrader: (4)

I'd vote for the MAF. Classic symptoms, trying to, or stalling when arriving at a stop.

Really bad news if it is, 'cos they are expensive. Run it in if you like and we'll run the diagnostics over it.

CERTAINLY don't drive it hard on boost until you have it fixed - you might lose the top off a piston if it is the MAF.

David APi

ScoobyDoo69

iTrader: (17)

Thanks David, really appreciate your help as always!

Am going to check it over tonight for any loose hoses, pipes, connectors etc. Then take out the MAF and try the brake cleaner, then give it a quick drive tonight if I get chance. If not then I will drive it tomorrow to see if it has helped. If still the same after checking the other things listed above I shall drop you a line, David

Come to think of it, the car has done similar one two occasions that I remember not too long ago, but then it was fine and I thought nothing of it. So maybe the MAF has been on it's way out and now needs replacing...

If it needs a new sensor then so be it, rather a new sensor than new engine!

ScoobyDoo69

iTrader: (17)

Just took the MAF off sprayed it with brake cleaner. Quite a bit of black came off to be honest, just leaving it to dry, will refit and go for a drive later.

Fingers crossed!

ScoobyDoo69

iTrader: (17)

After cleaning the MAF, the car seems to run a lot better, but am being cautious with it for a little bit to ensure it is running ok.

Thanks for the advice all.

APIDavid

iTrader: (4)

I still think you ought to pop in and let us run the select monitor over it. It might seem to be running OK, if the MAF is working, but out of its design voltage range, it could still do harm. Won't take 5 mins and you'll be a lot happier.

No charge of course ..............

ScoobyDoo69

iTrader: (17)

Definitely David. My plan was to give you a bell anyway as I want a mini service doing too, so I will give you a call to book in when I get chance.

Thanks
Kosta

KAS35RSTI

iTrader: (73)

Good news! Used MAF of a low mileage car wont be alot. Just make sure you get it of a reputable seller.