UKC

UKCers,

Recently had an absolute nightmare with my 05 Ford Focus (Mk2), clutch went, which is fair enough after 75,000 miles, but then the other day it started running very rough and misfiring etc. Got home and looked at the spark plugs, all seemed ok, gave em a clean etc. Then the car REALLY struggled to start!

Took it to the garage, they changed the spark plugs and leads, but the computer gizmo was still saying that number 4 cylinder was misfiring? they did a compression test and no 4 cylinder was "slightly" less in compression that the other 3 cylinders.

The car is definitely running smoother than it was, but still has the engine management system warning light on and at idle runs rough and doesn't accelerate as quickly (as you'd expect with only 3/4 cylinders working).

I have since replaced the coil pack and also put in an additive to the fuel to clean the fuel injectors and also lubricate any sticky valves... again, slight improvement, but still showing engine management warning light and running rough at idle.

Any ideas as to what could be the issue here? Anyone experienced similar with Ford Focus?

In reply to birdman:

Which engine?

PP.

In reply to PontiusPirate:

Sorry 1.6 ltr Durateci think

In reply to birdman:

If the computer says Cyl4 is 'misfiring' it'll only be one of a few things it can actually detect: Coil/amplifier fault on Cyl4 (pack shared with Cyl1?), plug/lead fault (if there are leads) or out of spec' fuel injector (these may fired in pairs on this car rather than sequentially, Cyl 1&4 so the fault could be in either if there is one). Of course it could be some other fault leading to an erroneous error code like a loose plug or a chaffed wire. It could also be an historic error code that was never cleared and is unrelated, the problem may lie elsewhere.

Why did they test compression, just because they could while the plugs were out? The ECU has no way of determining whether a particular cylinder is underperforming, only that the connected sensors/drivers are.

The ECU warning may need to be manually cleared.

I'd suggest you take it to a garage that knows their way around the engine and its diagnostic tools. If the ECU light is on it'll be holding the clues needed for someone with the right knowledge/manual.

jk

In reply to birdman:

How do you drive it - lots of towing? My mk1 Focus has done 170k and my Dad's mk2 has done just shy of 100k on the original clutches.


Does it do this from cold? I had an Escort that ran fine when cold but ran badly when warmed up - turned out one of the plug leads was faulty and was breaking down when hot. You say you've replaced all the leads, though, so probably not that.

In reply to LastBoyScout:

Re driving style, it was second hand, i drive it sensibly and don't rag it around but these things happen.

the issue is very recent, and hasn't presented a problem previously.

In reply to jkarran:

don't know why they tested compression, just that the result was that the cyl 4 was slightly down on the others?

Noted you comments regarding the ECU, will have to see what the dealership garage thinks maybe?

I've heard that it could possibly be a faulty wire from the cylinders to the sensors, but also if the coil pack was buggered, it may also have damaged the ECU apparently, which could account for the error code?

cheers for input anyway guys!

In reply to birdman:

Fair enough


Do you know what the exact fault code is and tried Googling it? There's also a Focus owners forum that might be able to help.

In reply to LastBoyScout:

If you dont know the code and dont have an OBD reader (I got a USB one for about a tenner off ebay, definitely worth it if you want to do any work yourself) the you can find the fault code by starting the engine whilst holding down the mileage reset button on the instrument panel. It'll go into a test mode, if you keep pressing the button you go through various funtions until the mileage lcd reads 'dtc' followed by some numbers and letters. This is the fault code.

The most comprehensive list for focus fault codes I've found is here: http://www.fordownersclub.com/forums/topic/9596-ford-fault-codes-the-full-l...

In reply to birdman:
Mine did this. Injectors. (found after much mucking about, and the garage eventaually had to tke the car to a dealership where they had a computer that could pick up the fault).

Mine's a diesel turbo.

Replaced all injectors (pricey). Sorted.

Sx

In reply to birdman:

A common fault on late 00's ford petrols is failure of the cylinder head coreplugs, situated between the sparkplugs. These corrode and leak, causing tracking and misfires.

Pull the plug leads out and have a look in the well between the camshafts (where the spark plugs sit). Does it look damp, with "rusty" deposits? If so, remove the cam cover (carefully, the bolts corrode and snap) and inspect/replace the two core plugs visible between the sparkplugs.

Cheers Adam

In reply to butteredfrog:

An even more common (and ridiculous) problem is rainwater draining through the windscreen washer jets and filling up the plug wells every time it rains - mine were about an inch deep in rusty water when I bought it, I'm amazed it ran at all!

So, if you do as Adam suggests and you see a rusty water colouration, don't automatically assume it's the core plugs - it could just be caused by water entering through the bonnet.

ps - this is dead easy to fix.

In reply to birdman: My old 55 plate had a similar problem, multiple attempts to fix by a couple of garages (new plugs, leads, coil pack) ended up being traced to a faulty wire within the connection plug to the ignition coil (easily damaged during dis-connection / re-connection)

In reply to John Ww:

Good point John. That's what corrodes the core plugs in the first place.

Cheers Adam

In reply to butteredfrog:

Any ideashow easy it is to replace the core plugs?

Cheers, John

In reply to John Ww:

Hi John

Pretty simple,
Off the top of my head.....

Empty Header tank

Remove
plug leads & coil pack
Coil pack bracket
Cam position sensor
upper cambelt cover
Slacken two bolts securing cambelt back plate to cylinder head (this allows you to flex the plate out of the way when you remove the cam covers)
Cam cover(s)
(be careful removing the cam covers as the bolts can snap, a gentle teasing is required)

Either tap a Phillips screwdriver through the core plug (corroded) and leaver out, or tap core plug in at one side to twist, and remove with pliers.

Tap new core plugs in flush (pence from ford dealers and they will be the correct size). I use a jointing compound when fitting core plugs, Welseal or similar.

Reassemble In reverse order

Top up header tank.

Cheers Adam

In reply to butteredfrog:

Much appreciated,

cheers, John

In reply to birdman: When mine started to run rough the garage diagnosed a breakdown of the "electronic distributor" (I live in Holland and this was my understanding of the mechanics description).