club.liberty.asn.au

Hi

On cold start the idle idle on my MY04 GT is unusually high, around 1500rpm. A quick blip of the throttle immediately restores it to a normal level. Idle is normal on hot starts.

Is this normal?

Also, when the engine is hot and the outside temperature is high with the air con on and and in D the idle tends to hunt between 500-1000rpm. It never stalls but again seem unusually, is this also normal?

Matt

O2 sensor

Thanks Zach

Are there two O2 sensors, one either side of the cat? If so would you recommend replacing both or is one or the other known to be a common fault?

Matt

It's normal

dr20t wrote:It's normal

My understanding as well. I recall someone saying its to get the oil moving faster, particuarly for colder climates? (please correct me if Im wrong)

Totally normal. The changing in revs with the air con running is just the air con cycling on and off. Nothing to worry about.

Dual avcs of the prefacelift 2.0 litre needs higher flow to prevent cavitisation

dr20t wrote:Dual avcs of the prefacelift 2.0 litre needs higher flow to prevent cavitisation

Wouldn't higher flow encourage cavitation or am I missing something?

Deep Heat wrote:

dr20t wrote:Dual avcs of the prefacelift 2.0 litre needs higher flow to prevent cavitisation

Wouldn't higher flow encourage cavitation or am I missing something?

Higher pressure with lower flow would lead to cavitation

Because the avcs buckets are pressure operated, oil pressure is high on startup.

Combine that with cold oil, cavitation is likely

Way to prevent it is increase actual oil flow - thus higher revs (and the 12mm factory oil pump compared to 10mm for most other ej's and 11mm for dual avcs ej257) will allow more actual flow

matt_linegar wrote:Hi

On cold start the idle idle on my MY04 GT is unusually high, around 1500rpm. A quick blip of the throttle immediately restores it to a normal level. Idle is normal on hot starts.

Is this normal?

Also, when the engine is hot and the outside temperature is high with the air con on and and in D the idle tends to hunt between 500-1000rpm. It never stalls but again seem unusually, is this also normal?

Matt

I have this issue too and my local Subaru stealership charged me for diagnostic time + upper cylinder cleaner + neutral switch over the first two consultations. I fitted the the neutral switch myself after the second visit and sent it back for the third time to have the car 'relearn the idle' but nothing really changed to be honest. I wouldn't describe it as normal as I never had the issue before, but I'd guess it's a sensor issue. The problem is I don't like swapping everything to fix the issue as it's an expensive way to go about it, hence I asked Subaru to diagnose it but half the mechanics out there don't know much more than the DIY enthusiast. Keep me posted if you figure it out. I haven't changed the O2 sensor as yet.

I should add that my engine hunts for idle every time I drop into neutral too...

Aircon issue at idle is no the AC Clutch kicking in and out, it is the factory base idle timing table allowing rpm to drift

cooki_monsta wrote:

matt_linegar wrote:Hi

On cold start the idle idle on my MY04 GT is unusually high, around 1500rpm. A quick blip of the throttle immediately restores it to a normal level. Idle is normal on hot starts.

Is this normal?

Also, when the engine is hot and the outside temperature is high with the air con on and and in D the idle tends to hunt between 500-1000rpm. It never stalls but again seem unusually, is this also normal?

Matt

I have this issue too and my local Subaru stealership charged me for diagnostic time + upper cylinder cleaner + neutral switch over the first two consultations. I fitted the the neutral switch myself after the second visit and sent it back for the third time to have the car 'relearn the idle' but nothing really changed to be honest. I wouldn't describe it as normal as I never had the issue before, but I'd guess it's a sensor issue. The problem is I don't like swapping everything to fix the issue as it's an expensive way to go about it, hence I asked Subaru to diagnose it but half the mechanics out there don't know much more than the DIY enthusiast. Keep me posted if you figure it out. I haven't changed the O2 sensor as yet.

I should add that my engine hunts for idle every time I drop into neutral too...

That is a different issue to the above

When I said it was normal, I was referring to the idle at cold start being higher

What you're referring to is hunting, which indeed is not normal. That is sensor related. Most likely a/f and maf. Might even have a vacuum leak somewhere.

dr20t wrote:That is a different issue to the above

When I said it was normal, I was referring to the idle at cold start being higher

What you're referring to is hunting, which indeed is not normal. That is sensor related. Most likely a/f and maf. Might even have a vacuum leak somewhere.

Exactly what I'm thinking!

So the advice so far is vac leak, O2 sensors or MAF, does that mean mass air flow meter? Also do you air/fuel when you say "a/f"?

Any tips on diagnosing these cheaply?

Matt

...and thanks for the advice that the cold start idle is normal.