Engine hesitation/flat spot (Liberty 2.0R)

Posts specific to the 2.0 litre NA engine

Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby bigBADbenny » Fri Sep 20, 2019 8:46 pm

Yeah, I was going to suggest checking timing the old school way :)
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Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby paulc » Tue Sep 24, 2019 11:37 pm

fyi, I had to buy another car, a 2007 Subaru Impreza, nearly new by my standards, they don’t build them like they use to but at least it goes. I’ve left the year 2000 Subaru Outback Limited with the garage, they’re keen to find out what’s wrong with it. They said they may swap the ECU or the engine so I’ll let you know what they find. Thanks for your help bigBAD, have fun.
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Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby bigBADbenny » Wed Sep 25, 2019 5:37 am

But wait there’s more! Ha ha :)
Good luck with the new one!
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Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby paulc » Thu Oct 03, 2019 10:07 pm

The garage fixed it; they had to change the engine in the Outback so I now have two Subarus. The problem was probably caused by a blown head gasket but we will not know for sure until they remove the heads on the old engine. The thinking is; there was a small water leak into the cylinders that gets worse as the engine heats up. They also said the bottom radiator hose was not getting hot so there’s probably a blockage somewhere. I now have to decide which car to keep, I think it will be the old Outback.
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Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby davo123 » Tue Dec 10, 2019 9:08 pm

Hi,

Sorry folks I don't know much about cars. I have a Subaru 2006 Liberty wagon, 2.0 automatic. Owned for about 10 years. On advice we use premium fuel (from Caltex).

Over the past 6 months or so it has started to hesitate, particularly when moving uphill (even a very slight slope) from a standing start. As soon as the engine "catches" revs properly and then drives nicely, but it can take 10 or 15 seconds to "catch" (ie: stop hesitating). It may have crawled 10 or 20 meters in that time; this can be particularly fun if I'm at a set of lights... If the car is warmed up it is much less likely to hesitate, but it still does occasionally.

I've owned a few cars, never had anything like this happen previously.

Suggestions? We took it to the garage a few weeks ago, they fiddled with it, but couldnt find anything wrong (it did drive nicely again for a few weeks, but its started playing up again now).


regards
Dave
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Sharpie UEC fuel rail soak trick

Postby bigBADbenny » Tue Dec 10, 2019 10:27 pm

If everything suggested in the previous posts checks out, try the Subaru Upper Engine Cleaner (UEC) fuel rails soak.

This was a tip shared by former Subaru technician Steve Siladi aka Sharpie on the lib club Facebook group, in response to a gen4 GT rough idle diagnosis post.

Fuel rails and injectos UEC soak:

Pull fuel pump fuse.
Cycle starter to reduce fuel pressure in rails, short cranks as to not burn out starter motor.
Remove fuel rail hoses supply and return where convenient and according to FSM procedures.
Use compressed air to blow remaining fuel from fuel rails.
Fill fuel rails/lines with UEC.
Let it soak, eg overnight.
Use compressed air to blow remaining UEC from rails/lines.
Reattach hoses as per FSM procedure, replace fuel pump fuse.
Key on to acc, prime fuel rails, check for fuel leaks.
Crank engine and pray :P

Alternatively, whilst soaking the fuel rails in UEC, remove the spark plugs, pressurise the UEC in the fuel rails (get creative here, eg use compressed air, pressure bleeder etc) and crank the engine using short cycles again.
Use compressed air to blow any remnant UEC from the cylinders, replace the spark plugs and resume the rails/lines soak.

The general idea is to use UEC in the rails, lines and injectors, instead of getting your injectors cleaned or replaced.

In general, proper diagnosis includes but it not limited to basics like compression test, inlet and exhaust vacuum tests, and in the case of a modern car logging the performance of the various sensors used by the ecu.
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Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby lexicanman » Thu Feb 20, 2020 11:44 pm

klam wrote:
NS_SHERLOCK wrote:Hey all.

I want an actual fix, something that will be permanent.

I was thinking an aftermarket ECU.

Any thoughts?


my car is hassle free since. except the dash rattle! :lol:



So it's been forever but anyone actually fixed this or sold up (gave up) Hahaha
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Re: Engine hesitation/flat spot (Liberty 2.0R)

Postby bigBADbenny » Fri Feb 21, 2020 1:55 pm

A simple inlet pressure test will do wonders.

I’ve noticed my Learning Views were going negative in the airflow ranges, meaning an inlet tract vac/boost leak: negative across the board, pointing to a post throttlebody leak.

I made sure the key was set to acc, opening the dbw throttle plate slightly.

I used a 12v tyre compressor attached to a tyre valve with the core removed, inserted into the end of a bean can that fits the inlet after the airbox.

Or you can just blank the inlet after the airbox and find another hose to apply positive pressure, 1psi is heaps.

Run the compressor and go nuts with dilute dishwash liquid in a spray bottle.

Look for any bubbles with a strong led torch.
Then turn off the compressor and listen for hissing.

I found leaks at the bov ref hose, rhs head breather hose and a big one, rhs rear lower inlet manifold gasket!
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