4G63 question

[Subaru ETA]

My Airtrek has the 4G63 turbo engine from the evo 7 GT-A. First question does anyone know these engines well?

The problem is it has what can be described as a miss fire. Usually happens when giving it light to half throttle. Usually when coming off a round about or entering a motorway. It is intermittent - it will do it once a day for a week, then go away for a month! It has also intermittently developed a slight "miss" on start up.

The plugs looked a bit shot so i replaced them. I thought I had it fixed but it has come back. I have tested the coil packs (runs wasted spark system) and they seem fine. There are no codes and no engine light.

I have taken it to the dealer who had it for a day, double checked everything I had done, did some data logging and they are at a loss! Doesn't help that it would do it while they had it!

I'm now thinking EGR or oxygen sensor? Anyone got any ideas?

[elnevio]

Have you checked the leads? Could be the start of one breaking down.

We had this on the RVR when we first got it. It eventually became quite obvious when you removed the lead, as it was shorting through the shrouding to the head!

[Subaru ETA]

yes i have, and the dealer has as well apparantly. But now you say that, when i did the plugs it went away (first i regapped them which stopped it, but then i repleaced them). maybe having them on and off so many times has caused one to start to beak down...

ill take a look when it has cooled down abit

[Subaru ETA]

have just pulled the EGR valve out and given it a good clean. put it all back together and it is still the same.

the leads tested ok but later tonight when it is darker ill run it with the covers iff and jiggle the leads and see if they arc

[Subaru ETA]

hmmm - the long lead test at 5.71ohm and the short 2.7ohm so i am happy with that.

When it is idling however, if i move the long lead , the idle drops, then comes back.

[BEG4ME]

I had a bit of a similar problem but worse and only when engine was warm. turned out to be the spark tracking down the coil-spark plug boot. Also i've seen the boots fail and completely arcing through the rubber to the head as Nev has said. Would be a good idea to check for tracking either on the old spark plugs or inside the boots and leads. You're looking for a greyish lightning kinda pattern.

[Subaru ETA]

Yeah there is no tracking (I'm a mechanic by trade ). Should have brought a Mazda being an ex Mazda tech!

I'm thinking that the long lead may be the culprit. However, when I move it around with the ohm meter connected it doesn't change the reading by much. Im prob going to chuck a set of leads at it and see what happens

[BEG4ME]

Mazda, good one. Haha. Although, a bit off topic here, but the 2.3 turbo 323 thing sounding quite a fun little drive.

[Subaru ETA]

Mazda 3 mps - awesome little car! I would own one if I had the coin

[Ryan]

Would rather have the Mazda 6 MPS... been in one as passenger and it was most enjoyable. I'd definitely buy one of those cars based on looks, spec level and performance

[Subaru ETA]

Would rather have the Mazda 6 MPS... been in one as passenger and it was most enjoyable. I'd definitely buy one of those cars based on looks, spec level and performance

Pity they don't make the 6 mps anymore

[BEG4ME]

http://www.trademe.co.nz/motors/used...-384812753.htm
That but turbo and manual would be my choice. Rare though. Not available stock in 4WD manual turbo, as far as i'm aware.

[Subaru ETA]

They never did a turbo wagon but you can get a HKS turbo kit which is very straight forward to fit. Wouldn't fit a turbo kit to a 2002 though - they had a smaller sump

[BEG4ME]

Anyway, back on topic. could you not just make up a temp. spark lead to test? You would probably have all that gear in the workshop, yea? Even using an old lead off a different vehicle (obviously not a faulty one) or borrow one.

[Subaru ETA]

That's the problem - I have a desk job now so no workshop!

I'm going to go see my Nate who is a auto sparky, see what he has laying about

[Ryan]

That's the problem - I have a desk job now so no workshop!

I'm going to go see my Nate who is a auto sparky, see what he has laying about

Is it this Nate by any chance?

[Ryan]

Double post.

[BEG4ME]

Mechanic with a desk job? Almost unheard of. Haha. Yea sparky *M*ate should definitely have something to try.

[Subaru ETA]

Stupid cars! I checked it last night and it was fine. This arvo I put it all back together, started it up and it running like a complete sack of ****! Idle is quite rough and has a miss just off idle.

I was talking to a different MATE today and he said he may actually have a near new set of leads off a late model Evo in his tool box so he will have a look on Monday. ( he was the Subaru mechanic at everyones favorite car dealer fast 4s!)

[Ryan]

Heh, hope it all works out Dave. Sounds like this one is particularly frustrating.