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Blackstar

Huge misfire

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Had slight misfire on idle for the past few months, slightly lumpy and twitching rev counter. But was pretty fine while driving including accelerating.

 

Booked in for spark plug change today and it's now massively misfiring on idle and driving/acceleration.

 

Any ideas on what the garage could have done? They assumed it was like that before hence why I brought it in for plug changes. They said it could be compression or injectors but is a big job so will need it back for a couple of days (which I am doing). I think they said they knew which cylinder it was and that they'd changed the coil packs over so it wasn't that?

 

Can't help but think they have damaged/disturbed something by accident, seems coincidence that it was running relatively OK this morning but also also acknowledge it was probably a problem waiting to happen!

 

Thanks in advance, would just like an idea as I'm not great on engines and don't want to be a totally ignorant customer.

Edited by Blackstar

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Not unknown for the coil packs to be incorrectly connected to the wrong plugs.

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3 minutes ago, Ebized said:

Not unknown for the coil packs to be incorrectly connected to the wrong plugs.

You'd hope not but it's true the plugs on the passenger side aren't connected in the order they leave the harness however it should be obvious from the lengths where they go.

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They will have got cyl. 4 & 6 mixed up:

 

Just swop them back:

 

cylinder layout 350Z - MY350Z.COM - Nissan 350Z and 370Z Forum Discussion

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Thanks very much for that guys will give it a crack tomorrow.

 

What causes the smell just out of interest? Absolutely hideous and lingering in the cabin for hours!

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Sorry for the double post and continuing to be thick...but am I OK just to swap the wire's over rather than take the packs themselves out?

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Wires swapped, running sweet as a nut. Thanks very much again guys.

 

Lesson learned for a dummy like me haha.

Edited by Blackstar

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1 hour ago, Blackstar said:

Wires swapped, running sweet as a nut. Thanks very much again guys.

 

Lesson learned for a dummy like me haha.

heh good stuff, although annoying a garage managed to put them back wrong :/ it's not a huge mystery if you look at the harness

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Well the story doesn’t quite end there I guess because when I go out for a drive there is definitely a loss of power compared to before the plug change (but a lot better than what it was before wire swap). Engine management light was flashing before wires swapped correctly but stayed on until I drove 10 miles. It’s now not on at all. Maybe engine is trying to sort itself out after the 6 miles I drove with them wrong?

 

Cheers in advance.

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Well, if they can not hook your coils up in the correct order, then I would be looking at the spark plugs (wrong type, wrong gap) and also all the 3 pins in each coil in case they have bent or damaged them.

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9 minutes ago, Blackstar said:

Cheers - plugs at least should be right as I got them myself!

What plugs did you provide the garage with?

 

What year and model is your car?

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2 minutes ago, Blackstar said:

Bosch double iridium

 

2004

And the Bosch part number or a link to your purchase.

Trying to establish if you have purchased the correct plugs for your particular model.

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From eBay: Spark Plugs 6x FOR NISSAN 350Z 02->07 3.5 VQ35DE Z33 Bosch Double Iridium

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46 minutes ago, Blackstar said:

From eBay: Spark Plugs 6x FOR NISSAN 350Z 02->07 3.5 VQ35DE Z33 Bosch Double Iridium

That does not help I am afraid.

I would require the part number or a link to the eBay listing.

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19 hours ago, Blackstar said:

Wires swapped, running sweet as a nut. Thanks very much again guys.

 

Lesson learned for a dummy like me haha.

Good news, but as Alex says given the garage cocked up with the coils and if you did not specify the correct plugs adds to suspicion they were not not careful about plug choice.:dry:

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OK so there were two codes on that my old machine couldn't detect. Both wiped and the power is back to normal now.

 

Still sounds a bit weird but is an exhaust leak I think, probably from all the shaking under misfire :lol:

 

So virtually the end of the story. Cheers all.

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Got a P0430 code now. Searching the forums it seems an exhaust leak can possibly cause this?

 

Also is it possible that running for 6 miles or so with two coil packs wired wrong way round could have buggered the cat slightly? Any way of cleaning it if so? Seen all the additives and stuff but not sure if any good at best of times, let alone for this. I reckon there is a slight whooshing noise from the exhaust towards about 5,000 revs plus. Exhaust seems quieter than before as well, less of a hum on motorway.

 

MPG seems unaffected.

Edited by Blackstar

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2 hours ago, Blackstar said:

Got a P0430 code now. Searching the forums it seems an exhaust leak can possibly cause this?

 

Also is it possible that running for 6 miles or so with two coil packs wired wrong way round could have buggered the cat slightly? Any way of cleaning it if so? Seen all the additives and stuff but not sure if any good at best of times, let alone for this. I reckon there is a slight whooshing noise from the exhaust towards about 5,000 revs plus. Exhaust seems quieter than before as well, less of a hum on motorway.

 

MPG seems unaffected.

Leave it on idle and stick your hand underneath to see if you've got an exhaust leak somewhere in the system. You can normally feel the breeze against your hand if you do

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