ScoobyDoobyDom

Hi
I've just recently bought a V plate Turbo 2000 with Performance Pack. It's my first Subaru so I'm not entirely sure what to expect. I do know one thing though, ...it goes like poop through a goose, except for a very mild hesitation under sensible driving (eg: town, off turbo) but only noticeable in 2nd gear on its pick-up upto about 2500/3000rpm. If you nail it through 1st/2nd/3rd, you wouldn't notice it. It is more noticeable before the engine has fully warmed up, but even when warm it is still there. Like I said, it's very mild and can only really be described as a 'kangaroo petrol' effect and only occurrs before the turbo comes in. It runs with Optimax and Super Plus - both have the same effect. It's going in for its 52,500mile service next week, am I gonna be stung for hours of investigation time or is there a common issue I should know about?
Any ideas??? Dom

Matt P

Welcome to scoobynet

They all do that sir. Lambda sensor runs open loop til it's warm and the surge effect can be quite noticeable. If it's doing it when it's warm you might need to replace the sensor but it's an easy job and not too expensive (less than £100).

Hope this helps

ScoobyDoobyDom

Thanks for the reply. No one else has replied to this so therefore methinks maybe its not as common as you explained. I can sort of understand about the 02 sensor but is it really going to be this harsh? I was driving home from work this evening after letting it warm up for a couple of mins first, and even after 10 > 15 mins driving it was still there. Its like a mild misfire as if the coil pack is breaking down or perhaps a dodgy HT lead. If you boot it in 1st/2nd/ 3rd its not there. Only there when im behaving myself Am I the only one with this going on under the bonnet?

stevem2k

Nope mine does it too, but only for a couple of miles , it feels like a gentle surge, and is right at 40mph.

Steve

Micka

Got an MY99 and mine used to do exactly the same.

Took it to the dealer and they couldn't find anything wrong on the computer and assumed it was a lead problem.

Replaced set of leads (Expensive £100+) and that seemed to sort it for a while.

Needed to replace a faulty O2 sensor after car failed MOT emissions.

Run on Optimax and problem seems to have gone for now!

AvalancheS8

My '97 does this too, but really only until it warms up. I believe the problem is related to the ECU running closed loop for emissions reasons before it's really warm enough.

supersarbs

Hello,

I've got a very similar problem on my new scoob (my00 ppp) - I am going to pop it up to xtreme scoobies for them to check up tomorrow(good excuse to see what mods to put on it!), so I will let you know what they say to me about it.

Flat Faw

MY00. Exactly the same 2nd gear syndrome as you. Just learn to live with it.

PhilA

There's 2 issues here. The hesitation when cold is very common on scoobies, not sure if there is a cure for that one, but it goes away when it's warm so. The other is your hesitation under sensible driving arounf the 3K mark. is it definately only in 2nd gear? Mine does this in everygear when driving sensibly but always at about the 3K mark. Not sure what is is yet? Anybody know why the O2 sensor would be this specific?

Scott.T

iTrader: (2)

it may be that 3K is the point at which is switches from closed loop to open loop mode i.e from 02 AFR control to MAF AFR control.

or 3K is roughly where you go from negative to positive boost pressure, hence also causing the ECU to switch modes as above.

if you have an AFR gauge you can work out where this occur as the LED's will go from pulse mode (closed loop) to constant (open loop). On my old MY94 is was pretty much as described above.

I've not got an AFR working in my MY00 at the moment, so can't confirm on the later ECU.

I have heard tho' that different plugs can help. I think the slighty better PFR7's IIRC

supersarbs

Just arrived back from Xtreme Sccobies - MAF turned out to be gone.

Very chuffed I made the effort to go as we all know what a kn@ckered MAF does...

Best get yours checked out though.

Cheers


Pete

PhilA

My MAF is brand new and it still does it.

nom

When cold: the ECU switches to using the lambda sensor before it's warmed up, simple as that. Ways round it? Change to an ECU that doesn't use the lambda... or switch to a lambda sensor that warms up quicker
When warm: all scoobs have a 'lean spot' at spool-up - this is made more acute when using an induction kit or more straight-through exhaust system. Changing the fuelling parameters is the only way round this... there's also a 'silent drive-by' thing built into the ECU which means if you floor it in either 2nd or 3rd - can't remember if it's either or both, sorry - then it releases control of the wastegate, so you'll only get half boost. Not very helpful, but it means it passes drive-by regs for noise levels.

MAF's something to look out for indeed - it under-reading when it's breaking can cause huge problems, and the dealer's diagnostic systems can't tell if it's breaking, only if it's broken. And it's at its most dangerous when it's simply mis-reading... a reasonably good way to check it is to do an ECU reset & see how the car idles (when warm) - lumpy & it's quite possibly on its way out, especially if it's a MY99/00; if disconnecting the MAF makes the idle better, it's almost certainly not in a good way . Also, once changed to a new MAF, it's a good idea to do an ECU reset otherwise the ECU will be using the values it learnt from the dodgy MAF to calculate the fuelling, hence potentially pants performance.

Erm, that's all I can think of for now

PhilA

I do have a de-act downpipe and a back box.

supersarbs

Update - This morning it was still a bit 'surgey' when cold, think I'm now down to the normal trait now.

It feels alot better now, and the ECU has been reset and is 'settling' itself in, seems alot more responsive.

For the sake of a few quid - i'd definitely reckomend popping to a specialist so they can confirm if the MAF is on it's way out. definitely piece of mind...

tailfin

MY00. Exactly the same as you. Just learn to live with it

The_Judge

If it is "2nd gear syndrome", you could try a manual boost controller such as GBE or Dawes, which will take boost control away from the ECU. You don't necessarily have to increase the boost... but the option's always there in case you decide to...

Just make sure you have a boost gauge to set it up properly, and a Knocklink if you decide to increase the boost from standard.

TonyBurns

iTrader: (3)

Everyone is incorrect here, sorry peeps
Its an emissions control feature thats built into the ecu to comply with EU standards, it cuts the boost to 1/2 so it can pass a roadside test etc.
Its biggest effect is if you sit in 2nd for more than a few seconds then floor it, best to change up straight away to 3rd, this will cure it

Tony

PS, yes you will find that all MY99/00's do that, but MY00's are probably more noticable.

The_Judge

Am I...?

TonyBurns

iTrader: (3)

Yup, the second gear syndrome as you put it is built in to the ecu, a boost controller wont do much if the ecu backs down the boost (or else you will be given the option of doing another emissions test within 7 days which no doubt will cost you )
Hesitation on the other hand is slightly different, you suffer it in all gears when the car is cold, running super unleaded or optimax will pretty much cure this (well i found it did )

Tony

PS, 2 ways around the 2nd gear syndrome, blip the throttle or change gear

The_Judge

The ECU backs down the boost by using the wastegate solenoid. If the hose to the wastegate solenoid has been removed from the T-piece, has a bolt in the end of it, and the boost is being controlled by a MBC, the ECU has no way of reducing the boost! It thinks it has (which is why the hose is plugged and not simply removed), but it hasn't.

I know this to be true, because I had a boost gauge fitted prior to my GBE, and could see the boost halve in 2nd gear, under the circumstances already described. Since fitting the GBE, not once has this problem occurred...

PS, those 2 ways also work.

timbo2000

I have an MY00, standard except SS back box and ITG filter. Had it from new and it didn't take me long to realise that using standard unleaded was the main cause of stuttery delivery at low rev's. Now using optimax - everything is fine.

The_Judge

Doesn't help further up the rev range either...!

PhilA

Mine is hesitant in ANY gear if I'm sitting at 2500/3000 RPM?????????

nom

2k5-3k is typically where the turbo spools up. So yes, especially if you are using the MAF/on standard ECU map, you'll get 'hesitancy' in any gear at that rev range.
It can be reduced by either blocking the airflow up more to where Subaru intended it to be (hah!), or fiddling with the fuelling. Or ignoring it, driving round it, etc.