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2 cylinders cut out when engine gets hot


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Hi, hoping someone out there can help/ give some thoughts

 

I have a 1998 legacy gt-b station wagon

 

took it in 2 months ago to get a new clutch (flywheel etc). picked up car and car stopped on way home (5 mins later). shop gave me a tow. Engine was misfiring, then cut out completely. engine really underpowered (snails pace).

 

wary that it might have been something they did, shop took it back, plugged in their computer thing and it told them that it was air intake sensor. so they changed it. did not work. still worried they 'went over it with a fine tooth comb' and could not find anything mechanical. they passed it to an electircal specialist who went over grounding etc etc (not sure what else, but they had it for months).

 

Now a third outfit has car. they are electrical too (and hence think it is electrical problem?!?). They convinced me that they had to go back-to-basics to diagnose. changed plugs, coils. still no fix.

 

My current understanding is that car idles ok, but when it gets hot two cylinders cut out. next thing the mechanic is proposing to do is to change a relay or something. I am scared that something 'simple' has been missed and all this is futile.

 

any clues anyone? pleeease. starting to feel like i am throwing cash into a big hole. I have no idea and will just pass on info to mechanic(s). Seems more than coincidental that car should not work after clutch replaced - but can't think they would have been near anything that would cause misfiring when pulling out clutch, gearbox etc.

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When it is acting up, shut it off, then unplug the front O2 sensor. It will set a code, but if it runs, the front sensor is your problem.

 

This has happened to quite a few people I know. When cold, the engine runs in 'open loop' mode. But when it gets warm, it switches to 'closed loop' and the sensors output becomes more critical.

 

Easy test to try.

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Someone here recently had the same problem. Turned out to be the igniter on the firewall.

If the two cylinders that cut out are paired 1&2 or 3&4, it's certainly possible that the igniter is failing when it gets hot. Once it acts up, a voltmeter in the hands of someone who really is an "electrical specialist" should be sufficient to determine if that or something related is the cause.

 

On the other hand, if the problem cylinders aren't paired as I mentioned, which two are they?

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Hi, thanks all - well impressed with swiftness of response(s). Just ran through suggestions with the guy working on car...

 

john in KY: I saw that someone posted similar problem re. igniter on firewall. I hoped it would be that. Apparently there are separate igniters on my particular model, on each coil. They have swapped these/ changed and ruled it out. never mind.

 

ferret: Love your name. Asked about 02 sensor. they did exactly what you suggested, ruled that out too. guy confirmed stuff about open/ closed loop. Problem starts at 85-89 degrees when running 'closed loop' mode.

 

OB99W: same re. the igniter. I should take back me reservations about guy looking at car, he seems to know his stuff and have tried everything. it has got him pulling his hair out. he did voltimeter check with laptop. This made him think coils were the problem (they weren't!).

 

Anyway. Another symptom transpired last night. Shop ran car for extended period and coolant starting dripping out at back end. Seems significant??? Shop doing a few more checks but are swaying (back) to possible mechanical problem.

 

Expecting call later today. will keep you posted.

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...well, 'coolant starting dripping out at back end' apparently not significant - took out intercooler went through it and all wiring. nothing.

 

Mechanic working on car now pretty much out of ideas.

 

- checked cam angle sensor ... ok

- rechecked grounding... no noise, no grounding.

- gone though all plugs pulling out, putting back... nothing

- swapped computer ... no difference

- did compression test ... all good.

 

Any other suggestions??? Pleeeease. No more money, going to have to loose car if no fix. Now desperate! Anything!

 

Problem starts at 85-89 degrees when running 'closed loop' mode. Engine starts to splutter, then 2 cylinders cut out.

 

does anyone in new zealand wanna buy a lemon of a subaru gt-b with brand new clutch, tyres, coils, spark plugs, computer and sweet stereo?

Pleeeease!!!!

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Seems like too narrow of a window when the problem develops to be anything but a sensor. But poor conductivity of the plug wires could also cause a weak spark not to be able to jump the plug gap due to increasing compression as the cylinder and piston rings warm up. Long shot I know, but going "back to basics" really does have to mean going back and checking the most basic of basic components required for the engine to run.

 

It's like saying that the fuel pump must be dead after changing all 4 injectors, and the ECU, chasing a no start due to lack of fuel, only to find out the tank was empty all along. :rolleyes:

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It's like saying that the fuel pump must be dead after changing all 4 injectors, and the ECU, chasing a no start due to lack of fuel, only to find out the tank was empty all along. :rolleyes:

 

Why that is perfectly logical and an argument that is sometimes made here!

 

:lol:

 

 

I love how the fuel pump gets blamed for everything.

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Yep, car is a 1998 twin-turbo GT-B station wagon with Bilstein struts, and from what I gather it has coil-on-plug ignition system. It was japan-import, real nice too.

 

Have asked technician/ mechanic to stop looking at it now, blown every penny I have with no luck - i think he has given up anyway. Lol! Considering looking at it myself ... how hard can it be right ?!?!:-\ He is going to write down everthing he has checked, rechecked.

 

Don't have much faith that i'll ever get it going to be honest. Suspect it'll be going for parts.

 

Going to see the guy tomorrow. Will post what he tells me - he seems to know what the problem is to the nth degree, but not the solution. frustrating (and expensive). Will give update tomorrow....

 

Thanks for everyone's thoughts.

 

ps....erm...forgive my ignorance...but could it be the fuel pump realted? that has gone twice in 12 months (was under warranty the 2nd time). not sure anyone has looked at it really. suspect not....but i wouldn't actually have a clue ;)

Edited by aegis1980
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We in the "colonies" sometimes forget that you guys "down under" get different models than we typically see here. So, does the car we're talking about have a turbo (twin?) with coil-on-plug ignition?

 

I was wondering what that whole GT-B thing was all about. :lol: This would mean that my whole "plugs n wires" theory is out the window. :rolleyes:

 

But that opens up a whole plethora of other options for what it could be depending on how closely Subaru monitors the turbo system and what sensors they use to do it.

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