Alloytec V6 misfire, dealer says rebuild...

[tHe_sTiG]

If it's OK when over a certain RPM, I very much doubt an electrical issue. I'd say a valve is sticking open and at higher RPM it slams shut more which explains poor compression on 1 cyl. Maybe a top end clean might help if it's a carbon buildup around the valve but best way to tell is to remove the inlet manifold.

Alright, it seems we're on to something here. The dealer suspects its either a stuck or broken valve... if that indeed is the underlying problem, repairs and labour will cost a hell of a lot less than an engine rebuild. Let's hope that's all it is. The cylinder in question is cylinder 3.

 

[Smashfist]

Alright, it seems we're on to something here. The dealer suspects its either a stuck or broken valve... if that indeed is the underlying problem, repairs and labour will cost a hell of a lot less than an engine rebuild. Let's hope that's all it is. The cylinder in question is cylinder 3.

Depending on how much the valve sticks open you're up for an engine. Only way to tell is to rip the head off, but in 95% of the broken valve/spring cases I've seen the piston munches the valve/head because alloytecs run a flat top deck and there's no clearance for a valve to be hanging around occupying piston space.

 

[tHe_sTiG]

Update:

Mechanics removed the top of the engine and had a good look... concluded we needed a new engine. The guys went out looking for a used engine from the junkers. They found one, went about their inspection and decided it was in decent shape.

I've got the car back now, took it out for a good drive in the city and out on the highway... everything seems fine. Fortunately, total cost, around $3000, has been covered by Dad's employer / sponsor... so we've got ourselves a free engine.

 

[routier1642]

That sounds like a good decision and a better result!

 

[tHe_sTiG]

More update:

Dashboard and centre console lights all dead... didn't realise until I switched on the lights at night... we'll have to see what that's all about...

 

[1ntercept]

Yeah, that's bull s***. Looks like they were fishing because of a slow work shop day, or had an abundance of spare parts that need paying for. I'd start with plugs and coils. You'll be fine.

 

[tHe_sTiG]

OK, lighting problem was simple enough, just a blown fuse. Fixed now. The give-away was the tail-lights... and is it turns out... I was driving around with no tail-lights last night! Good thing I wasn't pulled over!

Engine, so far so good. Done about 200 km's of highway and city driving, no unusual signs. Much quieter now too since the engine mounts were replaced.

 

[Onyabuddy]

I’ve got the same problem happening on cylinder 2, I’ve tried 2 different spark plugs and coil packs no difference. Also swapped the the “possible” faulty coil pack to cylinder 1 and the coil pack from cylinder 1 onto cylinder 2 and still playing up on cylinder 2 so isn’t the coil pack. I’m thinking of maybe switching the cylinder 1 spark plug to cylinder 2 and so forth to see if it changed to cylinder 1 and then I’ll know for sure that’s it’s the spark plug and then it can be replaced (will get back to how this goes). Any suggestions would be great

 

[krusing]

Maybe a faulty injector?,

I had a similar issue not long ago,
And removed all the top hardware,
Cleaned it all up, inc ground connections,
Replaced the spark plugs, and 2 coils,
And fixed the issue,

Is it only 1 cyl missing missing ?

Where are you located at n Melbourne ?
As a JC’s member maybe able to assist you if you close to them.

 

[Onyabuddy]

Maybe a faulty injector?,

I had a similar issue not long ago,
And removed all the top hardware,
Cleaned it all up, inc ground connections,
Replaced the spark plugs, and 2 coils,
And fixed the issue,

Is it only 1 cyl missing missing ?

Where are you located at n Melbourne ?
As a JC’s member maybe able to assist you if you close to them.

Yh just cylinder 2 not 1 and Yh located in Melbourne