mk5 fiesta 1.25 misfire

Matt Tenpenny · 06-01-2010, 05:32 PM

hi, at 1st the fiesta would have a intermittant misfire when cold but then as it got warm it would disapear.just lately its got worse,even when hot.

now it does it perminantly now. now i am quite good with mechanics but this has me totally confused.com

there is no sign of head gasket damage
ive changed the plugs
ive tryed different leads
coil works as i get a spark when the spark plug is removed and earthed on something metal

The misfire is coming from number 4 pot and its doesnt get any better or worse with the ht lead removed.

tottally flumuxed.

any help would be gladly recieved as my local ford thieves sorry dealers want £80 for a diagnostic.

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clarke5700 · 06-01-2010, 05:35 PM

have you tryed a compression test? or swaping the injector out of the problem cilinder for one of a good cilinder? to see if the problem changes to a different cilinder?

Matt Tenpenny · 06-01-2010, 05:39 PM

its not the injector as the spark plug gets sooted up and it stinks of unburnt fuel.

but i havent tryed a compression test.

Lloyd · 06-01-2010, 08:25 PM

coil pack is a common problem. even if its sparking to earth,when its in the cylinder under pressure,it wont work.
ps, 80 quid diagnostic,could be cheaper than randomly replacing parts,hoping to cure a problem

Ginger Will · 06-01-2010, 08:33 PM

There was a thread about this the other day and I'm sure someone said you can use a Zetec coil pack of a focus 1.8 or 2.0? I'll see if I can find the thread...

http://passionford.com/forum/ford-fo...r-misfire.html

admittedly a Focus, but its the same basic engine I think?

Matt Tenpenny · 06-01-2010, 09:39 PM

well after me and my dad had a chat about the problem i remebered that when the radio is on i get interference in the way off a small clicking noise,not when the cd is on,just the radio.

my dad said go and watch the leads with it running while its dark,move them around and tell me what you see.

well upon doing this i discovered that the leads are very slightly arcing across each other and onto the rocker cover.
when you rev the car the flashes and tiny sparkes get brighter.

so im going to buy a brand new set of leads.

i also discovered that spraying wd40 on the leads stopped this for a very short time.

watch this space to see if the new leads work tomorrow!

06-01-2010, 05:35 PM	#2
clarke5700 YES I KNOW I CANT SPELL Garage is empty, add now Trader Score: (0) Join Date: Mar 2008 Location: chingford e4 Posts: 4,878 Rep Power: 8	have you tryed a compression test? or swaping the injector out of the problem cilinder for one of a good cilinder? to see if the problem changes to a different cilinder? __________________ " im special,, excuse my spellings"

06-01-2010, 08:25 PM	#4
Lloyd escort mk4 cossy 4x4 Garage is empty, add now Trader Score: (0) Join Date: May 2004 Location: coventry Posts: 4,633 Rep Power: 12	coil pack is a common problem. even if its sparking to earth,when its in the cylinder under pressure,it wont work. ps, 80 quid diagnostic,could be cheaper than randomly replacing parts,hoping to cure a problem __________________

06-01-2010, 08:33 PM	#5
Ginger Will Too many posts.. I need a life!! Garage is empty, add now Trader Score: (0) Join Date: Nov 2006 Posts: 663 Rep Power: 6	There was a thread about this the other day and I'm sure someone said you can use a Zetec coil pack of a focus 1.8 or 2.0? I'll see if I can find the thread... http://passionford.com/forum/ford-fo...r-misfire.html admittedly a Focus, but its the same basic engine I think? Last edited by Ginger Will; 06-01-2010 at 08:41 PM.

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06-01-2010, 05:39 PM	#3
Matt Tenpenny also known as mini idiot Garage is empty, add now Trader Score: (0) Join Date: Sep 2007 Location: coventry/telford Posts: 217 Rep Power: 5	its not the injector as the spark plug gets sooted up and it stinks of unburnt fuel. but i havent tryed a compression test.

06-01-2010, 09:39 PM	#6
Matt Tenpenny also known as mini idiot Garage is empty, add now Trader Score: (0) Join Date: Sep 2007 Location: coventry/telford Posts: 217 Rep Power: 5	well after me and my dad had a chat about the problem i remebered that when the radio is on i get interference in the way off a small clicking noise,not when the cd is on,just the radio. my dad said go and watch the leads with it running while its dark,move them around and tell me what you see. well upon doing this i discovered that the leads are very slightly arcing across each other and onto the rocker cover. when you rev the car the flashes and tiny sparkes get brighter. so im going to buy a brand new set of leads. i also discovered that spraying wd40 on the leads stopped this for a very short time. watch this space to see if the new leads work tomorrow!

06-01-2010, 09:39 PM
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