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  #1  
Old 15th February 2018, 07:27 PM
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Default Call for help XV 2012/3

This has also been posted on the facebook page but there may be some knowledgeable non FB people.
Appeal for help!!!!!
My grilfriend Sally's daughter has an XV ( 2013or2) and had an incident ( just riding along type) and needs some help. She is a midwife and has just started a new position and MUST have her car and it has to be reliable . Now I know she should have bought a Corolla but she didn't.
So far I only have sketchy details but some thoughts on diagnosis would be appreciated.
She was driving home and the car started making a "funny noise" and stopped . She managed to get it home after it did start but kept making a noise. Mobile mechanic said it was a coil in no.4 cyl. Replaced coil and no difference.
Any experiences that may help.
Sorry that is currently as much detail as I have and I live 350km away so I can't check myself.
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Old 15th February 2018, 08:53 PM
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Either take it to an experienced Subaru mechanic or (shudder) a stealership.

Do NOT do a hard reset of the ECU as this will clear the diagnostic codes.
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Old 15th February 2018, 11:42 PM
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More detail: Engine lights all on. Motor will start and run with loud mech sounds. Coil was replaced but made litle difference ( prob was faulty but not the cause of this). More interestingly the brakes were stiff. So possibly not getting vacuum. But it runs? Does the vacuum only feed from one side of the manifold?
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Old 16th February 2018, 12:03 AM
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Ok now I am even more confused. The racq guy said it was coil number 4 cyl.
The vacuum for the brakes comes from number 3 cyl.I just went and checked mine and the vacuum line for the brakes come off quite close to the No3 inlet. So possibly number 3 isn't drawing a "vacuum". Why no code for number 3 cyl.?
Beginning to sound valve bendy or conrod/piston self destruct. Is that a reasonable possibility for an XV FB20?
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Old 16th February 2018, 12:18 AM
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Sounds unlikely. When my '68 Landcruiser broke a piston into 3 bits, it didn't just make a noise, it went DOLLAR DOLLAR DOLLAR!

Broken engines tend to make very loud noises, and you tend not to be able to drive them home!

There are exceptions to these, but they're the exception, not the rule.
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Old 21st February 2018, 04:09 PM
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A local subie guy ( local to Sal's daughter) went around and checked it . Ex Mechanic. Bloody champion. He took a code reader and did some digging. He is gonna check it out but suspects at first glance it is crap fuel or simply insufficient maintenence . We wait to see the results.
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Old 21st February 2018, 05:19 PM
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Quote:
Originally Posted by gregjet View Post
The vacuum for the brakes comes from number 3 cyl.I just went and checked mine and the vacuum line for the brakes come off quite close to the No3 inlet. So possibly number 3 isn't drawing a "vacuum".


Now - if there's no brake assist, and engine is running rough, the first thing I'd suspect is a vacuum leak.


(an aside) - the intake runners are all part of the intake manifold - connected at the plenum. All cyls are pulling vac on that line.
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Old 21st February 2018, 05:54 PM
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"(an aside) - the intake runners are all part of the intake manifold - connected at the plenum. All cyls are pulling vac on that line."
INCORRECT
The brake line intake is a considerable distance down the intake runner near the head. In the Common plenum the average vacuum will be pretty mauch the same. But the nature of how the lower pressure ( not actually a vacuum) is produced by negative wave pulses traveling back from the valve face means the pressure in one runner will be a function of the valve opening of that cylinder. The pulses occur fast enough for the pressure in the runner to be different from not only the other runners but also the plenum ( 330kph approx).
If the valve is stuck open enough it will be sending both positive AND negative pressure waves along the runner. That will raise the overall pressure in the faulty runner and reduce the pressure differential in the plenum. That will inturn reduce the air velocity through the throttle body and cause furthur engine problems in the other cyl.
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Old 12th March 2018, 11:47 PM
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My guess on this is poor maintenance.

I'd be dropping the oil and seeing what comes out with it - also cut open the current filter and see what's hiding in that.

From what I've read in here my gut feeling is it's oil related and much greater than the codes you're reading - they may be secondary issues that are unrelated to the main issue of the noise that you're chasing.

For your sake and your GF's daughter's sake I'm hoping I'm wrong. Ring or bearing issues = big dollars if not DIY'ing the work yourself (properly!).

These engines run a very thin oil, irregular oil services or poor oil quality can cause dirty oil quickly or oil blockages that cause other issues

Cheers

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  #10  
Old 19th April 2018, 06:54 PM
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Turned out you were right. all coils sick as well and no compression on one cyl. We await the final autopsy and conclusion. Thanks for your help.
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