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Rough Idle Yet Again

PostPosted: Fri Jan 27, 2017 3:55 pm
by 04_LibertyGT
Hi all I'm new to the forum and I have used the search engine for rough idles. It seems to be a well documented subject but instead of searching for a fault that a lot of people seem to struggle with due to the many potential faults, I have decided to get an independent Subaru specialist to take a look at it.

There were a couple of guys recommended on here but I decided to go with Lucas Automotive in the hope they can data log the issue and start diagnosing. They seemed knowledgeable over the phone as you would expect from a specialist. I previously used Tony from URD Automotive and he was great and I would highly recommend him if you are out Knox way. However, I had a wrx at the time plus Lucas Automotive is closer and gets a good rep on here.

Anyway mine is an auto 04 Liberty GT with 180kms on the clock and the rough idle is when stopped both in drive or neutral. It almost wants to stall when coming to a stop sometimes and the idle issue is when engine temps are both cold or hot. I bought the car with the idle issue and it didn't develop whilst I owned it.

If they find the fault, I'll post the issue in the hope this can one day help someone else.

Thanks!

Re: Rough Idle Yet Again

PostPosted: Fri Jan 27, 2017 10:37 pm
by bigBADbenny
Happy to log n lv in Melb :)

Re: Rough Idle Yet Again

PostPosted: Sat Jan 28, 2017 9:37 am
by 04_LibertyGT
Thanks Benny. Pm sent.

Re: Rough Idle Yet Again

PostPosted: Sun Jan 29, 2017 6:55 am
by Bigwillystyle
Hi buddy,

Welcome to the club..

We fixed mine yesterday.. Was smooth for 30 seconds and then rough. Give it some Jandal and ot would come good and rough as it dropped to a stall at times..

Turned out to be lack of fuel pressure caused by a oring that was pinched in the fuel filter.. For that matter I wouldn't discount the fuel filter at those klms either..

May or may not solve your issue but checking fuel pressure by grabbing the rubber fuel lines under bonnet was what gave it away.. especially when the scan shows no faults

Re: Rough Idle Yet Again

PostPosted: Sun Jan 29, 2017 4:15 pm
by GTWAGON06
I have the exact same issue with my 05 at the moment. Driving me nuts! Cant get any to figure out what the problem is!

Re: Rough Idle Yet Again

PostPosted: Sun Jan 29, 2017 9:46 pm
by 04_LibertyGT
Thanks i'll get the fuel pressure and vacuum leak checked at the same time. It has been driving me crazy as well but so many potential faults. I would rather let someone with the expertise look at it as I could be chasing this forever. I'll post up what the issue is once i know. I'm booked in for next week.

Re: Rough Idle Yet Again

PostPosted: Wed Feb 01, 2017 6:07 am
by bigBADbenny
Also worth checking the fuel pump plug pins under the rear seat below a screwed on cover, look for burnt pins in the connector..

Re: Rough Idle Yet Again

PostPosted: Fri Feb 03, 2017 1:26 pm
by 04_LibertyGT
Thanks i'll take a look over the weekend.

Re: Rough Idle Yet Again

PostPosted: Tue Feb 07, 2017 7:31 am
by 04_LibertyGT
Just picked the car up and the potential list is -
Plugs
Injectors
Timing issue

The guys were helpful and great breakdown of potential issues in detail but i'll need to do some work to keep cost down.

I'll do the plugs over the weekend as i don't know the history of the car and its a good starting point. Since its not throwing any codes they advised to wait but this rough idle is really bugging me. I'll do plugs first then if that fails, I'll pull out the injectors to get them tested/cleaned.

I also wonder if the K&N panel filter could have been over oiled by the previous owner and damaged the afm. I have tried contact cleaner to no avail. I know they are really sensitive to oil on the wrx and cleaning doesn't help. Probably changed 2 in 7yrs of owning a wrx.

Suggestions welcome.

Re: Rough Idle Yet Again

PostPosted: Tue Feb 07, 2017 4:23 pm
by bigBADbenny
Ditch the k&n go stock filter n box if everything else is stock, crc maf cleaner on the afm and check the o ring is sealing & not pinched.

Re: Rough Idle Yet Again

PostPosted: Sun Feb 12, 2017 9:56 am
by 04_LibertyGT
New plugs went in and cleaned the maf with crc cleaner but still not fixed. Also took the opportunity to do a top engine cleaner spray, dropped the oil and changed the oil filter.

At this point I think its injectors, from what i read on here they are a common issue along with wheel bearings on libertys. I'll clean the throttle body when i remove the injectors just in case its sticking as well.

Does anyone have recommendations for an injector cleaning place in the SE suburbs?? I would want them flow tested after cleaning and would have to be cheaper than buying new ones.

Re: Rough Idle Yet Again

PostPosted: Sun Feb 12, 2017 4:08 pm
by 04_LibertyGT
Update - Stalled twice today. Once when sitting at the lights and the second time was scary in a turn. It shut down, I lost power steering and barely managed the turn without mounting the curb. This is getting dangerous.

Re: Rough Idle Yet Again

PostPosted: Sun Feb 12, 2017 6:37 pm
by Surge
Bigwillystyle wrote:Hi buddy,

Welcome to the club..

We fixed mine yesterday.. Was smooth for 30 seconds and then rough. Give it some Jandal and ot would come good and rough as it dropped to a stall at times..

Turned out to be lack of fuel pressure caused by a oring that was pinched in the fuel filter.. For that matter I wouldn't discount the fuel filter at those klms either..

May or may not solve your issue but checking fuel pressure by grabbing the rubber fuel lines under bonnet was what gave it away.. especially when the scan shows no faults


I'd second this.

Change your fuel pump and filter. Ensure you use the correct size o-rings in the correct location.

Re: Rough Idle Yet Again

PostPosted: Sun Feb 12, 2017 7:22 pm
by 04_LibertyGT
Thanks for the input. I'll try the lines under the bonnet. Unfortunately fuel pressure wasn't tested last time it was in the shop but i'll drop it off this week. From what i know the fuel filter is part of the whole fuel pump assembly with the liberty??

Re: Rough Idle Yet Again

PostPosted: Mon Feb 13, 2017 5:57 am
by bigBADbenny
Great idea^^, also gives you the opp to check the fuel pump top loom connector, and the connectors below: the plug is a known failure point - look for a burnt pin.