scooby_hater

Car has just developed missfire sounds like a impreza also just before the missfire happened there was a rattle from the cat like a loose heat shield had a look and all welds are there and not loose need help badly as i need it for work Thanks

Glenn_

iTrader: (1)

The first thing i would be changing is the plugs plus the leads and the coil pack.Im sure the coil packs are common for breaking down and causing misfires.

scooby_hater

Could it also be the cat??

johnny99

Hardly, but the leads do give trouble,

John

RSturboJET

Leads go like lightbulbs, happened to my 2ltr.
The cat is probably falling apart inside and is causing an obstuction, but its definitely not the misfire problem.

blueskies85

cat wouldnt cause the misfire but instead of getting busy buying stuff why not check a spark from the coil first? Just get the centre plug off the dizzy (the one going to the coil pack) and bridge the metal piece to the block with a spanner or something, get matey to crank it over once or twice to see if you are getting a spark... that way youll now the problem is either ht leads or plugs, then do the same with each plug, connected to the lead put the metal threaded portion of the plug on the block and crank, if you see a nice strong blue spark move on to the next one.
If you find one with no spark or a shitty yellow one then check the resistance of the ht lead compared to a good one. If its ok you know its the plug (change them all) if its a shit resistance you know its the lead...
Im all for fault solving but proper fault diagnosis... not just change this and change that... i mean im not made of money so have learnt the above ways.... hope this helps!

Glenn_

iTrader: (1)

The zetec engines suffered from sticky valves but that was when they first come out.The cat could cause problems with the running of the car to.Normally when the cats get blocked,When you rev the engine the cats normally start to glow red.

blueskies85

oh and a word of warning... dont place your hands on any metal bits whilst doing the checks above, youll end up with a shock.. not life threatening just a "fookin ell" shock. Make sure your hands are touching rubber at all times when doing the checks above!

tabetha

Not quite sure what blueskies is on!!
I would check first for discharge around the plugs, if you have BOSCH plugs bin them, even if new, you are looking for streaks up the porcelain which will be grey in colour, some staining is normal and is corona discharge but will just be a uniform ring around base of porcelain, leaks are streaks of grey looking like jagged lightening up the porcelain, very common on these engines, but easy to cure too.
Ford recommend using silicone gel just on the inside of the plug cap so it forms a perfect seal on plug.
Coilpacks do break down, but mostly when tested in free air they will work perfect, but when under pressure in an engine they will not.
If a early type coilpack is fitted I always change these for ACCEL 140018 coilpack, about Ł65 but makes a noticeable difference.
If the cat is breaking up it can cause a blockage but not a misfire, normally it is the plug of cat material in the pipe itself that comes loose and bounces around but you'd hear it all the time, seriously loud rattle.
If a coilpack is suspected the quickest way is to just change it temporarily for a freinds one, to see, I think the ford ones are about Ł35.
tabetha

blueskies85

just trying to give some advice Tabetha thats all... Its the way i have checked for sparks when i have had misfires and it works... there are many ways to skin a cat i guess. It just frustrates me sometimes when people say to change this and change that when it probably doesnt need changing. I mean with the credit crunch and all I just dont have money to buy a brand new ignition system just because 1 cylinder is misfiring!

tabetha

I get what you are saying, and have the same policy of cheap/free fixes, but the zetecs don't have a king lead to which you refer or a dizzy, sorry if I was a bit snappy towards you, not my intention, I know you are only trying to help and it is appreciated.
tabetha

blueskies85

No i got the wrong end of the stick. i thought it was a erst for some strange reason... sorry for the confusion!