They all do it when cold. The ECU goes closed loop for emissions compliance, but a 14.7:1 mixture on part throttle from 2000-3000 RPM is too lean for a cold car. Disconnect the lambda sensor and it goes away - this proves that this is the problem as then the car runs open loop. Don't run like this continually though.

It is nothing to do with boost because the car is off boost. Some cars with blown MAF sensors are worse. It is nothing to do with the ECU. I've not seen a genuine proven ECU failure yet. Remapped ECUs do not fix the problem. Knock sensor modifications do not fix the problem.

It is an unavoidable consequence of achieving emissions compliance. Live with it. Don't know if the tumbler valves on the new age models help this or not.

If you get a warm hesitation that is a completely different matter.

BTW you can buy an ECU second hand which is as good as new for £75 which is the going rate in the for sale section. I buy them frequently to reprogram them.

[Edited by john banks - 7/4/2003 6:15:15 PM]

 

I recently bought a '00 X reg Impreza Turbo and have noticed that it is slightly hesitant between 2-3000 revs on part throttle particularly from cold (on full throttle it is perfect). I took it back to the dealer and the mechanic called it surging, it feels like a fuel problem of some sort. They tried a new Air Flow Meter but this didn't help, they then changed the spark plugs and on the advice of Subaru Technical disconnected the battery to reset the ECU. It does seem better now, but they implied it was not uncommon on this model and I may have to live with it, this seems a strange attitude on such a new car and I previously had an MY97 that never had any such problems. Has anyone else experienced anything like this???

 

I've 00 W reg turbo and similar to yours it suffers from surging of power (in 2nd and third gear in particular)especially when cold.She's going in to the garage next week to have it checked out . Over the phone the mechanic suspected the boost solonoid, but i'll find out soon enough, i don't know if this helps you any.
Treacle

 

It certainly sounds like the same thing, I'd be interested to find out whether or not they can sort it out, I only had mine done yesterday, it did feel much better this morning but I want to give it a week or so to really test it out.

Please let me know how you get on.....

 

hi i have a MY2000 WAGON TURBO which i bought 2 weeks ago,i also took it back with the same problem.They told me it was a standard characteristic of this engine(99MY/00MY) and gave a technical response from subaru which confirmed this.(technical service bulletin 1-1b-017).Does`nt seem very good though

 

Yep same problem withn me ...try a search , I think it comes up on here quite a bit .

Dave.

 

Paul i'll post you a reply when she comes out (so to speak) on the 15th July. As well as the boost solonoid they also mentioned the ECU and Mass Airflow Sensor so at least the mechanics are on the same wavelength. The surging i'm experienceing is certainly more than should be expected from any car . When cold my wifes Mazda 121 is smoother!!

 

Thanks for that and good luck, I've been looking at various other threads under the search "hesitation" and have found quite a bit more info on it, mostly relating to MAFs and ECUs.

 

My MY99 Wagon has had the same 'surging/stutter' from cold since I've owned it ... Sep 2001. After a few miles it's OK.

Wait till you get a 'stutter/missfire' when the engine is warm all over the reg range! (This is on boost and off boost)

Mines been back to the dealer 7 times now...

New MAF
New Oxygen Sensor (is that the lambda thing ?)
Boost Solenoid cleaned
Boost turned up to what it should be
Timing reset
Sparks plugs checked
Coil checked
HT leads checked
Exhaust checked
etc etc etc

Subaru are now going to replace the ECU! I still reckon it's the plugs or coil.

Still under warranty till Sep 2003, so I'm not complaining about what they've done ... and to be honest the dealer has been fantastic about the whole thing so far.

J.

 

Well that's something to look forward to!!!

Mine's warrantied til Decmeber, but I'm thinking of a 2 year extension after hearing some of these stories!

Does anyone know what an ECU costs out of interest, is it an expensive part?

 

Its a common problem on MY00's, pretty much everyone of them suffers from hesitation when cold so no matter what you do it wont fix the problem as its in the ecu (its down to the map they use for passing the emissions test).
A remap will cure it, thats about all that will really (but id like to say that my ford mondeo does it more than my scoob )

Tony

 

Tony, If you're refering to a TEK re-map then I'm sure it has no effect on the cold start hesitation.

Guy

 

Paul

ECU for an MY99 UK Turbo from my Subaru dealer (Gatwick) £550ish.

Even though my Scoob has a few problems, I still love it to bits. In 22 months of ownership this 'stutter/misfire' is my first real problem. The only other problem was a dead battery.

J.

 

John

Excellent response. £75 for 2nd had ECU is handy to know.

Any thing spring to mind on my "warm hesitation/stutter" problem? or is it a bit complicated?

J.

 

Warm hesitation can be loads of things - specialist or informed dealer needs to check out the car.

 

Thanks John, the problem is certainly worse when cold, but when I took it to the local dealer, it was warmed up and he said he could feel it surging on part throttle between 2 - 3000 revs. If it was just when cold I could live with it, but it makes driving carefully (and my girlfriend is pregnant so I have to at the moment) a bit of a pain, as soon as I put my foot down it's fine.

 

Treacle? Did you have any joy when you took yours in?

 

Paul, still not sure mate. Like yours mine suffers mostly when cold . After the 60 mile trip to where i bought the car she was somewhat warm . I took the mechanic out for a test drive and surprisingly she wouldn't play. A faultless drive, bugger. The garage cleaned the mass airflow sensor (slightly dirty apparently)and then reset the ecu with a full tank of optimax in the system . I'd used five fill ups on optimax before as well. She seems to be ok at the moment but it's too soon to tell . I went out yesterday and she was ok, today dare i say it my wife has taken her to work (i'm bricking it and have logged all the stone chips, and odo)so i'm not sure her she drove. The mechanic said that a dirty M.A.S which is common can cause a delay in acceleration mimicing a surging sensation . So we shall see. I'll keep you posted as to what happens, keep me up to date as well.
Treacle

 

Cheers mate, will do, I'll probably go back to the dealer next week as it doesn't seem much better. They seem to have the attitude that it's as good as it's going to get though which I don't think is satisfactory.

 

I have this problem on my MY00, the dealer keeps telling me it isn't a problem it's a characteristic, i might try and approach another dealer to see what they say.

 

Yes that's the response that I've got, but I figure every car of that model would do it if that was the case, and judging from the feedback here most seem to when cold but not when warm. I can't believe that Subaru would knowingly make a car that had "lumpy hesitating performance" as a characteristic!

 

Paul, forgot to tell you, they plugged her into a computer to run a fault diagnostics but that came up blank . I hope we can sort this problem out once and for all . It seems though that many drivers out there are having the same problems.
Good luck next week, Treacle