surging through the rev range particularly cold

[05gtwagonman]

Hi guys, I think Trieu said it best:

I think every car is different and every car has it's own demons...

Here's mine, see if you have any input.
Cold start, 200m, through roundabout, up soft hill, foot 1/4 throttle, soft surge at about 2200, then picks up on the turbo at 2900/3200 and pig roots up the road 100% 0% 100% till you push the clutch in and start the process all over again. It never happens the second time.
Now here's where i can throw most of you i think.
It has done it hot.
It constantly has little surges throughout the boost range no matter what conditions and Subaru's explanation is that this is normal. They agree that the desciption of the more severe hesitiation is not normal, and a Tech has made the car do this hot -thank god, so they don't dispute that it has done it.
They have done:
upper cyl hd clean
checked and cleaned the injectors
checked the coil packs
reflashed (fryed and replaced) the ECU (totally new now with the updated prog)
They can't find the problem, and at this stage we have given up. The car is out of wty soon, I think that a total tune should get rid of the problem any way, but I'm worried that there might be an underlying problem first though...
I moved last month, and the conditions in the morning have changed and it gets more time to heat up and do other things so I rarely feel the bad surge anymore. Could it be combination of the gravitational force and magnetic anomolies that naturally occur in the prievious neigbourhood. Could I be abducted at any moment? Have I lost my mind?
Any thoughts?

[05gtwagonman]

ahh aparently I needed to end the quote a little earlier... DOH

[WhiteGTB]

Heya bud

Ummm yeah.. I didn't write all that did I?

I think all I wrote was the Demon part. Pretty sure.

[Spec B Wgn]

is this car completely stock ??

i would say its a faulty 02 sensor or your AFM is on the way out.

[WhiteGTB]

is this car completely stock ??

i would say its a faulty 02 sensor or your AFM is on the way out.

Yeap, when I had that issue Paul from Pulse Racing fixed it, he discovered the Front 02 Sensor was working but not 100%.

Got a new one and the problem was solved.

[suff]

Hey Trieu

Was this diagnosed with an ECU error log? Or by trial and error?


Chris

[WhiteGTB]

Hey Trieu

Was this diagnosed with an ECU error log? Or by trial and error?


Chris

Hi Chris, I don't think it was trial and error... when Paul hooked it up the computer the graph that showed the air/flow reading for the rear sensor was jumping all over the place.

Up/Down whilst idling. Along with all the other graphs whiched showed as normal operations this was the only one that was showing as out.

A quick stop at the local Subaru dealership for a new sensor and the problem was gone.

Please NOTE: I am not sure if this was more a surging through the rev range OR rough idle issue. But from memory I called it a rough idle issue.

[05gtwagonman]

Hi Guys, sorry trieu, you were just the first bit, I'm a technical dullard
the car was completely stock until yesterday when I fitted a whiteline rear bar. Clearly that adversly affected the problem and Subi will tell me it's the cause Seriously, if it is something that can come up on the service monitoring computer( for want of the correct term) then I would hope that they should have seen it.
That said they clearly didn't in trieu's case.
It is going in for an unrelated cause on friday I will specifically get them to look at said o2 and AFM just in case and let you know later in the week. Anywhere else to look before it goes in?

[05gtwagonman]

Interestingly enough I was told that the o2 sensor or the maf would have logged an error had they been faulty, therefore Subaru didn't show even the slightest interest in looking closer at these. Trieu, and anyone else, if this has been a fault, has it been discovered on the error log at service, or can it be a problem without ah error being logged? thanks for any help you can give...

[Ric]

Why don't you take a drive down to Sydney, and let Impakt plug his ECUDATASCAN box into your OBD-II connector?

http://forum.liberty.asn.au/viewtopic.php?p=22170#22170

[WhiteGTB]

Interestingly enough I was told that the o2 sensor or the maf would have logged an error had they been faulty, therefore Subaru didn't show even the slightest interest in looking closer at these. Trieu, and anyone else, if this has been a fault, has it been discovered on the error log at service, or can it be a problem without ah error being logged? thanks for any help you can give...

Hey bud, from memory, Subaru did not look into the 02 Sensor cause it didn't show an error code.

Correct me if I am wrong, but error codes only show up when the device does not work. In this case the sensor was working but intermittently only. Therefore an error code was logged.

Once the car was hooked up to the computer, real time logging of data showed the Air Flow was jumping all over the place.

A possible solution might be for that particular dealer to pop in a new 02 Sensor to test?

Hope that helps.

[05gtwagonman]

Ok- the subi guys we still not prepared to change the o2 but they did an idle reset. This sounds like it should not have have had anything to do with the prob, but it certainly improved things. They were chasing a remenant of and older problem where if the car was off boost going up a slight hill it would "pig root" up the hill until it got solidly into the boost range. They pretty much fixed that but then the hesitations got worse, now having reduced the hestitations, the rootin's back. There is also some kind of pedal movement with the brakes that can be very unerving, dropping 1/2" or so like a drop in vacume, but not redicing, rather than slightly increasing the retardation. They are now saying that they belive the brakes are within the cars likely tolerances and behaving as expected, and I'm yet to talk to them about the accel issues.
Not the end of the world, but I love this car, and if i get pissed about this, i'll end up thinking that any old commuter will do. I don't wanna go there...

[fish_boy79]

hey rich which subaru dealership you been talking too?

[05gtwagonman]

The new Zupps capalaba one. I do have to say they have been listening to me and trying to get to the bottom of this. It's just that they are failing...

[Spec B Wgn]

The new Zupps capalaba one. I do have to say they have been listening to me and trying to get to the bottom of this. It's just that they are failing...

replace the o2 sensor