Turbo fitment confirmation & idle issue. UPDATE!

[Brend0]

Hi all,

Just wanting to clarify that a TD04HLA is a direct replacement for the VF38 and what is required to make fit.

Does the dump pipe have to be changed or is it the same on both manual & auto versions.
I have searched extensively but can not find a definate answer and also contacted PHAT GT but unfortunately haven't heard back yet.

Also i currently have an hunting idle issue which is there in & out of drive. The problem is not there when the AFM is disconnected its perfect. This leads me to believe that it is AFM but it has already had 1 replaced and the problem has not changed.
I did notice yesterday when i had the snap-on scanner plugged in that the hunting started only when the A/F Correction % began obviously when closed loop learning started it varied from -20 to 25%.

Other possibilities is O2 sensor faulty and AVCS solenoids holding the variable valve timing.

I have contacted PHAT GT for a replacement AFM & O2 sensor.

Does anybody have a full factory service manual to suit (my apologies i haven't searched for this yet)

Any info greatfully apprecated.

[zch91]

http://www.tangcla.com/temp/bl5/reference/

The above link can be found in the 'reference/walkthroughs' section

Don't be scared to search

[cruisn]

TDO4HLA is a direct replacement for the VF38 in every way.

Theres a Gen4 workshop manual on CD on Ebay for about $12. Very handy.

[Brend0]

Checked all hoses & gaskets for air leaks - none found

Also checked every injector operation and all responded the same.

Any possibilities before i order a AFM & O2 sensor?

[Matt_gt]

ive owned two gts now and they have both had that rough idle. hunting up and down. interested to see if u solve ur problem. i have had infectors cleaned and flow tested new afm plugs tryed everything!

[dr20t]

With that much correction its most likely a vacuum leak

Check all your hoses under the top mount intercooler

Also check your fuel regulator pressure line in engine bay this could cause a leak and rough idle

Could also be maf scaling being out but I doubt it if your car is stock

Good luck

Mick

[jslayz]

I had rougher idle before I did plugs and replaced the in tank fuel filter.
Idle is really regular now.

J

[Brend0]

With that much correction its most likely a vacuum leak

Check all your hoses under the top mount intercooler

Also check your fuel regulator pressure line in engine bay this could cause a leak and rough idle

Could also be maf scaling being out but I doubt it if your car is stock

Good luck

Mick

I will be removing the intercooler and checking all hoses but still makes me wonder that before closed loop begins this idle issue is not present. Which to me would indicate the ecu compensating for a false reading sensor.
It's near on for it's 50K service so will go right through it.

[rooby]

50000 on an '03, wow.

[dr20t]

Didn't realise it was ok at idle (post stated wad rev hunting in drive and out of gear)

Must be afm itself if that's the case as a vacuum leak will cause rough runnig across the whole range

Good luck with it dude

Mick

[Brend0]

Didn't realise it was ok at idle (post stated wad rev hunting in drive and out of gear)

Must be afm itself if that's the case as a vacuum leak will cause rough runnig across the whole range

Good luck with it dude

Mick

Must be misunderstood. The issue is at idle and is hunting in and out of gear. It idles fine when there is no A/F correction when in open loop. As soon as closed loop begins that is when the hunting begins. This is when the O2 sensor reading is also being used to achieve optimum air/fuel ratio.

50000 on an '03, wow.

It's will be its 150k service. The 50K is the same service.

[Brend0]

Just an update. Over the past couple of weeks my local Subaru dealer has been consulting with there tech support and after some data logging they came to the conclusion that the O2 sensor is faulty.
We replaced the O2 sensor today and the idle hunting issue is now fixed. Also the car is more responsive on light throttle and the instant fuel figures have improved with similar driving as before.
It turns out the O2 sensor whilst not giving a fault code appeared to be reading too slowly effectively giving the ecu false data, this was causing over compensation resulting in hunting of idle.