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Niles
Sunday 22nd February 2009, 21:54
I have a misfire under boost, had it before & I fitted a set of genuine (brand new) plug leads, seems the same symptoms to me. The new leads have done appx 5000 miles.
My car has a MSD Blaster uprated coil pack. SO, would the blaster make the standard leads fail early? Or are my plugs tired? There no misfire when I rev it up at idle, its only under load/boost.
Without breaking the bank, who makes a good set of leads that can handle the MSD? I know Magnicor make 'thick' ones, at the mo they're out of my price range.

Saaamon
Sunday 22nd February 2009, 22:03
From my own experience and going on the good things russ says, Volvo leads are the best choice for our cars.

timbo_1975
Sunday 22nd February 2009, 22:12
What plug gaps are you running? Anything upto 0.9mm with the MSD coil should be ok with the volvo leads- i would guess the rotor arm and cap would be the weak link in the chain though.

Change the plugs first before condeming the leads though, and don't assume the new plugs are correctly gapped out of the box (0.7mm)

shaun850
Sunday 22nd February 2009, 22:25
The plastic that sits down in the plug wells melt's on magnecors. did on mine anyway

Niles
Sunday 22nd February 2009, 22:29
What plug gaps are you running? Anything upto 0.9mm with the MSD coil should be ok with the volvo leads- i would guess the rotor arm and cap would be the weak link in the chain though.

Change the plugs first before condeming the leads though, and don't assume the new plugs are correctly gapped out of the box (0.7mm)

I cleaned my plugs today & set the gap to 0.7mm, before that they were at 0.6mm, the misfire was there before but to be honest it's worse after i set them to 0.7mm. I'll reset the to 0.6mm in the morning.
I turned my turbo down by 1 full twist on the actuator this evening, I'll report back in the morning as to wether it's had any effect.
I just bought a set of genuine Volvo Turbo plugs, what setting should they be out of the box?

timbo_1975
Sunday 22nd February 2009, 22:43
You definately have a very weak spot somewhere if you need 0.6mm gap and still getting a misfire.

What age are the cap and rotor arm??

The Flying Banana
Sunday 22nd February 2009, 23:26
perhaps the spark is getting blown out under load, what plugs are they ?

Tomcat
Sunday 22nd February 2009, 23:27
I'd defo start by checking/replacing rotor arm and dizzy cap.

Niles
Monday 23rd February 2009, 00:37
perhaps the spark is getting blown out under load, what plugs are they ?

Bosch super 4

Niles
Monday 23rd February 2009, 00:37
I'd defo start by checking/replacing rotor arm and dizzy cap.

wildo that in the morning (later lol)

Niles
Monday 23rd February 2009, 00:38
You definately have a very weak spot somewhere if you need 0.6mm gap and still getting a misfire.

What age are the cap and rotor arm??

errrmmmmm.......2 years'ish

Niles
Monday 23rd February 2009, 00:43
by the way, 16T turbo blows 18psi in 2nd gear (auto) 3rd & 4th 19-20psi. Car go's like a scalded cat off a polished shovel!!!! However, it'll still misfire at 10psi & will stop misfiring if i back off the throttle, if it 'feed it' in or gentle squeeze it up to 18psi it won't misfire. :cuckoo::cuckoo:

snoop69
Monday 23rd February 2009, 09:21
errrmmmmm.......2 years'ish

They are not that old bud - you replaced them shortly after i brought
my V70.

I would guess around 14mths or so.

Niles
Monday 23rd February 2009, 10:02
to be honest I really can't remember!

Niles
Monday 23rd February 2009, 16:06
today I changed the dizzy cap & the rotor arm, reduced the turbo boost & reset the plugs to 0.65mm, seems better but to be honest I'm not 100% happy with it. New plugs o'clock!!!!!!!!! (on their way to me).
Lets wait & see if it cures it.
Car is much better by the way.

Alan M
Monday 23rd February 2009, 18:59
Bosch super 4s are not really that good going by use on a previous car. They seem to get very very hot at the tip and I even had one break down and disappear down my cylinder. That car was a N/A 1.9 also so I would not like to use them on a turbo'd car. I'd change the plugs for genuine items or Bosch Ytrium have been good in my T5 when used and look very very similar to genuine items.

Niles
Monday 23rd February 2009, 21:14
I bought some genuine Volvo 850 Turbo plugs from a eBay Volvo dealer, I payed 21+ 1.99 postage. Pretty good price?
I've learned a lesson recently by putting genuine Volvo front brake pads in my car to replace some slightly cheaper pads. The Volvo pads are MUCH MUCH better. So that's me converted to a 'buy Genuine' driver now. lol

Saaamon
Monday 23rd February 2009, 23:49
Make sure you check the gap on the new plugs before you put them in. May i ask what map you are using Niles?

snoop69
Monday 23rd February 2009, 23:54
May i ask what map you are using Niles?

He has them set at just over 6 thou.

Ive told him to either slow down or burn it :firedevil

Niles
Tuesday 24th February 2009, 01:43
Make sure you check the gap on the new plugs before you put them in. May i ask what map you are using Niles?

Rica 304

Niles
Tuesday 24th February 2009, 01:44
He has them set at just over 6 thou.

Ive told him to either slow down or burn it :firedevil

slow down? 130mph with a misfire? lmao!!!

Alan M
Tuesday 24th February 2009, 07:36
He has them set at just over 6 thou.

Ive told him to either slow down or burn it :firedevil

6 thousands of an inch is very very small, don't you mean 0.6mm??

shaun850
Tuesday 24th February 2009, 07:51
Super 4's are pant's as are genuine plug's on an engine with raised boost.

Use platinum plugs plate or Bosch Ytrium, it will solve your problem.

Niles
Tuesday 24th February 2009, 10:58
6 thousands of an inch is very very small, don't you mean 0.6mm??

he meant 0.6mm

Niles
Saturday 28th February 2009, 22:57
I fitted new plugs, dizzy cap & rotor arm & still have a misfire under load. Next immediate suspect is the plug leads!! HMMMMMMMMM Bougicord leads fail at only 18months old?