Greetings from sunny Gibraltar! 👋

I have an 05 Focus mk2 saloon with the 1.6 petrol and 97,000km (60,000 miles). Highly reliable, hasn't missed a beat - until a couple of days ago when she struggled to start and when she did, she ran on 3 cylinders. I checked the spark plug wells and found them full of water. I parked her outside and it had rained quite hard.

I pumped out the water, dried out the wells and the HT leads as well as pulling out the spark plugs (they were replaced a couple of months ago) and dried them. I put the spark plugs back in, but made it a point to change them around. However, cylinder 4 still had a misfire.

I parked the car indoors to avoid the rain. Now the car won't even start. She cranks, but I can't even get her to fire on 3 cylinders. I'm thinking ignition coil - any suggestions?

Update: I've replaced the ignition coil but still have the same problem ☹️

Is there any white exhaust smoke when started up ?

2 hours ago, unofix said:

Is there any white exhaust smoke when started up ?

No smoke. We've tested the spark plugs and the HT leads, all working OK. Car now fires up after spraying brake cleaner into the intake. She runs and idles on 3 cylinders but when revved past to 2,000 rpm or higher, it seems like cylinder 4 comes back to life. 

Think you need to do a compression test.

20 hours ago, unofix said:

Think you need to do a compression test.

Indeed, hopefully there hasn't been internal damage from hydrolocking 1 or more cylinders 🤞

7 minutes ago, FatHead1979 said:

Indeed, hopefully there hasn't been internal damage from hydrolocking 1 or more cylinders 🤞

Fingers crossed, it ain't pretty!

On 4/2/2024 at 5:20 PM, unofix said:

Think you need to do a compression test.

I've got it booked in with a specialist to do just this. It's odd, because it fires up on 3 cylinders but if I rev it to 2,000rpm or higher, cylinder 4 comes in and the misfire stops.

Change coil pack, leads and plugs before you start panicking about it being anything else

10 minutes ago, DaveT70 said:

Change coil pack, leads and plugs before you start panicking about it being anything else

Changed the coil pack. The spark plugs are months old, tested them all and the leads, they're all working fine.

Just now, rockofgibraltar said:

Changed the coil pack. The spark plugs are months old, tested them all and the leads, they're all working fine.

Change the leads before you start panicking about it being anything else

Related to Dave’s reply above, you could try swapping coil packs and plugs between cylinders to see if the fault stays with the cylinder or moves with the plug/coil pack

On 4/2/2024 at 12:01 PM, rockofgibraltar said:

I put the spark plugs back in, but made it a point to change them around.

 

How about reading faultcodes?

Just one: P0304

2 hours ago, M0ndeo said:

How about reading faultcodes?

 

fuel injector - e10 *****? would be my guess

Maybe you should try to swap #4 injector to some other cylinder.

If it wont transfer fault to other cylinder , and compression test is ok.

Then i would be suspect wiring loom , since you have already replaced coil and plugs.

Check ht leads for sparks when its dark. Could be dump HT leaads, spark to the ground though damaged insulation and instead of going to spark plug just shoots to nearest ground point. 

On focus mk1 1.6i, it was recommendation to reduce gup in spark plugs from 1.6mm to about 1.3mm if I remember right,  as it was to much stress on HT leads and coil pack.

Update: Strangely enough, she fired up on 3 cylinders but when I started driving her, she smoothed out and ran on 4. She's been running perfectly on 4 ever since, even upon restart. I've left her with a trusted mechanic who will do all tests.

Update: car tested fine for compression, head gasket, fuel injection and spark/ignition. Mechanic cleaned the major electronics with contact cleaner and the engine warning light disappeared. Had timing belt and water pump replaced whilst at it. Just picked her up, she's running beautifully!

The drama ain't over just yet 😭 the Gibraltarian weather is beginning to average north of 20°C, so A/C is vital! It works perfectly when driving, but then on idle stopped cooling. Engine temp rapidly shot up, too 😣 narrowed it down to a faulty ventilator control unit. Popped a new one in, and we're back in business. Then I parked her, came back to her 30 mins later and...she refused to start.

Same issue: sounds like she's just about so start but nothing happens. She did it twice before starting up on the third try.

Now we've ruled out spark/ignition, fuel injection, compression and head gasket. Timing belt is brand new, as is thermostat. Then I got to thinking... This car is 18 years old. Although I hear the fuel pump working when I turn the key, could it be that an 18 year old fuel filter and fuel pump are failing to pass enough fuel/fuel pressure to the injectors? 🤔 Thoughts please! 💭

The Mk2 petrols don't have a fuel filter.

Update: Car starts and runs perfectly now, but on two random occasions it has failed to fire on all 4 cylinders. Nevertheless as soon as I begin driving, cyl 4 kicks in and stays running smoothly. The only other thing I've done to the car is to change from 5W30 to 10W40, but that was after the two instances.