darren760

Hi All,

Ive recently brought a 2000 reg uk turbo 2000,
Mods - turbo back exhaust, standered td04, forge dv, cone filter,
It did drive fine at first but only boosting at half a bar (restritive pill was missing) Now boosts 0.8/0.9 bar

Now i have an issue with hunting when hot ....?(No codes stored in the ECU)

Cold idle is fine, But when warm it hunts when coming to a set of traffic lights/junction it will almost stall and bounce up and down 4/5 times then idle fine ....?

Ive checked for vac leaks/boost leaks

Replaced the maff with a genuine subaru one £120

also tried the oem reserc valve (no change)

It also seems to be running rich and leaving a soot mark on the floor when starting from cold...? (Very poor MPG)

Any advice would be great as im at a loss...

FMJ

iTrader: (2)

Has it been mapped? It should have been with a decat. Also the cone filter is not required and will probably do more harm then good. I would take it to a specialist and get them to look at it. You could spend ages chasing sensors, plugs, coils etc without finding the cause and spending £100's.

darren760

Hi,

No its not been mapped..

FMJ

iTrader: (2)

I am assuming when you say turbo back exhaust you do mean fully decatted? If so that will probably be cocking things up. It may not be your actual problem but that and the cone filter are not going to be helping matters.

darren760

Yes its a full de-cat turbo back exhaust ..I don't hammer the car as i know the mods make the car run lean .(had a bugeye wrx with the same mods and that was running lean...Until Duncan graham mapped it )
This is my 3rd scooby

My point is the car was fine but now the hot idle is crap ...but the car boosts/runs fine ..?

Fizz

iTrader: (1)

lambda sensor fried?

darren760

Would that throw a code up ...?
And would that cause the hunting...?

TonyBurns

iTrader: (3)

That or the cone filter has fooked the MAF sensor up or even both.

OP, cone filters are a bit of a on the MY99/00 cars due to the maf sensors being a little sensitive, would recommend going back to the standard air box.
A full decat shouldnt affect you too much but you may get a little bit of overboosting in the cold weather, easy to sort out as all you need to do is drill the restictor plug out a touch or even better, have the car mapped.

Tony

piehole1983

iTrader: (7)

ECU been reset yet? Worth a try.

darren760

Cheers for the replies guys,

I thought it was just the pre 2000 cars that needed a ecu reset when fitting a new maff?

also can any of you tell me what the preset is on a TD04 (How many threads on the actuator arm is please..)

piehole1983

iTrader: (7)

I think they'd all need a reset after changing any critical control parts? Won't do any harm to reset it so you might as well do it.

Do you mean wastegate spring preload? I found a guide on here that suggests a preload of 4mm. You need to adjust the "eye" on the end of the actuator rod to a gap of 4mm past the pin on the flap arm. You'll need to pull the actuator rod out a little to place it back on to the flap arm again once adjusted.

darren760

Can i just disconnect the battery for a few hours...?

piehole1983

iTrader: (7)

Yes mate

darren760

Cheers i'll give it a go.. Thanks for your responses guys..

darren760

Well I disconnected the battery for about 4 hours and drove it steadily for about 7 miles and it still does it ...?
Also I booted it this morning and it was almost like fuel cut/boost @ 55mph I nearly went trough the windscreen ...?
I did manage to look t the boost gauge and it was only boosting @0.8/0.9 bar which is normal ..
I'm starting to think it could be a bad fuel pump .. was told to check the "Teabag" on the fuel pump ...?

piehole1983

iTrader: (7)

Yeah there's a filter on the bottom of the fuel pump that looks a bit like a tea bag I suppose. You might have a bad MAP sensor if you're getting fuel cut. That means the ECU is seeing boost higher than what you are. Is your boost gauge known to be reasonably accurate?

darren760

Well i think I've nailed it ....DUMP VALVE...I caught it out the corner of my eye,I have a forge twin spring dump valve its the small spring being to week and being forced open ..

darren760

I've just spoken to Forge, Its called the idle spring ..just ordered parts to recondition it ..and a few different strength idle springs..