Dougy Giro

Hi,

My My96 TypeRA has a mis-fire / spluttering / hesitation problem.
However it only does this when cold (and not all the time!!!)

I've been told by my local garage thats it definately the Coil Packs, another one says plugs!

I did a search on here and it could be virtually anything - Coil packs, plugs, MAF, Lambda, ECU, Water temp sensor (i've changed one, but someone says there are two) etc....

Anyhow my point is - How can it be the Coil Packs, and to a certain extent - the plugs????
Surley if these were faullty it would be a constant problem or at the very least intermittent and NOT dependent on engine/water temperature ???

Please help --- AAARRRRGGGHHHHHHH !!!!!!


Cheers
Dave


Editted to add - NOT

[Edited by Dougy Giro - 1/14/2004 11:07:03 AM]

Jolly Green Monster

iTrader: (4)

The coils have to work harder when cold..

Before I changed my coil packs I had a miss fire (running on three) when cold and damp start in the morning and the odd miss fire at high load around 4500rpm..

The plugs obviously use the coil packs charge to spark so you can get similar problems with faulty or old plug but most likely to be coil packs..

They seem to last about 5 to 7years or 100k miles I have found.

The heat just gets to them and they go brittle and crack and produce a weaker spark..

JGM

Dougy Giro

Thanks JGM,

Car has only done 45K, but it is 7 year old so if they aint been changed it looks like thats the problem. The brittleness with rapid heat absoption does make sense though coz i imagine its quite hot on top of those heads !!!


Still cant understand why they gota work harder when cold though, and i would expect it to do it a couple of times when warm, but its never missed a beat !!!


Thanks
Dave



[Edited by Dougy Giro - 1/14/2004 2:40:22 PM]

Jolly Green Monster

iTrader: (4)

Needs a stronger spark as the mixture is richer, engine is colder etc..

JGM

Dougy Giro

I'm gonna change them as a matter of course now as they are a 7/8 year old now - along with plugs.

How much differnece did you notice - apart from the lack of a mis-fire i mean. Any other benefits you noticed?

Cheers
Dave

dnb

I'd try new plugs first... Gapped to 0.7mm or 0.8mm (Not 1mm as it says in my Impreza manual )

The plugs made a massive difference to my car - Off boost performance was improved such that I could comfortably have the car in one gear higher than previous round town and I found another 1 PSI of boost Also, the fuel economy seems better, but I've not used a whole tank yet, so I haven't got numbers to share.

NGK plugs cost me £30ish from sparkplugs.co.uk in Scoobyshop. (Don't buy "cheap" plugs) IIRC NGK PFR7B is the correct plug for your car, but please check, as there are loads of different numbers, all subtly different!! (IMHO, getting the plugs first and seeing what happens would be preferable to a large bill... But then I'm terrible for not spending money!!)

I have one dodgy coil - the nose that fits over the plug is epoxyed together, but no other cracks. It's worth giving them a thorough looking at before purchasing new ones, as they cost £59 each. = £240 for 4!!

I have borrowed a set of coils and they made no difference to my car (80k miles, 6 years old) even with the bodge repair to one coil (have to stress again, this most likely wouldn't have let a spark escape anyway - It could just could let dampness into the contact...)

Best of luck.

Dougy Giro

Cheers dnb,
Will probably have to do that now coz i've just had and unexpected bill come in - not scooby related !!!

Thanks