Idle / Misfire With Focus C-Max

[Pioneer]

Hello,

I'm presently having some problems with my 2006 Ford Focus c-Max 1.6 petrol (30,000 miles) and I wonder whether anyone else has had any similar problems?

It started a few weeks back when the car would occasionally stall when slowing down (particularly slowing from speed). Normally this would happen when approaching a roundabout or similar which was not only dangerous but often difficult to negotiate out of :o !

I'm a reasonable DIY mechanic and so checked all of the usual bits plugs, leads, air fliter, throttle body (for soot / debris) and did a battery & alternator check) All seemed ok so we took the car to a local independant garage (Nationwide) who plugged it in but could not find a problem.

The issue worsened and developed into what could be described as a sort of misfire (butterfly style sensation felt through the floor of the car through the driving range and at idle). This was worse when travelling up hill etc. The car also seemed to lack urgency when accelerator depressed (as if power not getting through to the road wheels). When at idle the car would stall or try to stall if power was drawn from somewhere (i.e. elec windows operated). You can hear the slight misfire via the exhaust.

We gave in and took the car to the dealer who charged us £100 just to plug it in! They said that faults were showing for the TMAP sensor and the HEGO O2 sensor. Both replaced and £500 later (!) we collected the car. However, the problem persists and if anything it seems worse with fuel economy now through the floor (1/4 tank to 50 miles!).

We took it back to the dealer who plugged it in and found no faults. They suggested that the fault was the spark plus. Reluctant to fork out again I did these myself today (only cost me £10 as opposed t £100+ dealer price!).

The old plugs looked ok when I took them out but I still put new Bosch Super plus plugs (correctly gapped at 1.3mm> These have made no real improvement on the problem though I concede the car does seem to respond a little better than before.

I've ordered an ignition coil pack in the hope that it could be this. (Mine is the single square coil rather than the pencil coils fitted to larger focus engines). I was also going to change the leads if this does not work but they look fine.

Does anyone have any other suggestions or has anyone had any similar issues?

My model has no MAF sensor or Idle control sensor (things that have plauged me on prior cars!) and I'm at a bit of a loss (and £500+ down so far!!).

Grateful for any advice.

Thanks and regards :)

[stef123]

my money is on ignition coil

[artscot79]

my money is on ignition coil

ignition coil and /or leads as well though at 30k thats a bit much for them to go already if chenging these does not correct the issue then ide go back to the dealer with a list of all replacements and get it checked for idle undershoot its where the ecu needs updated as the current programme is allowing the cars rpm to drop too low when slowing or stopping end result is it stalls

[Pioneer]

Thanks for the replies.

The coil I ordered did not arrive today but is due in tomorrow. I'll fit it first and if the problem persists I'll do the leads as well. The dealer did (or at least claimed to) update the PCM with the latest software edition when the ran the diagnostic.

Fingers crossed it's the coil, finding the problem has already cost me too much money!

Having read some other posts I note that the seals on the Focus washer jets can allow water ingress. With all of the rain today, some did indeed leak through mine and had formed a small pool on top of the air filter housing. However, the C-Max, unlike the normal Focus has the bonnet at a slightly different angle and so any water leaking through goes nowhere near the spark plugs (as it seems to on the normal focus). However, it's possible this could have dripped into the vicinity of the coil.

I'm going to remove the washer jets and re-fit with a bead of silicone under them just to be sure.

Once I've done the coil I'll post an update.

[Pioneer]

Coil changed. It is a vVery simple task.

1. Remove HT leads (remember the order and where each goes). Fortunately both the leads and the new (bosch) coil have numbering on them which is helpful.

2. Remove the 4 x torx screws.

3. Lift the coil up and withdraw enough to gain access to remove the power connector (very difficult to do while the coil is in place, easy when lifted out and turned upside down).

4. The coil pack is now out.

5. Re-fit in reverse order

(easy). :)

Took it for a short drive, the feels better and so far it has not stalled. No misfire through the driving range either. Still a very slight 'butterfly' sensation on the idle but not enough to make the revs change. This could be normal (before the problems developed I never really studied the idle in any great detail). Hopefully all good but I will monitor with care over the coming days.

I also took the throttle body off and cleaned it thoroughly while I was under there. Again very easy to do.

1.Remove the air intake pipe leading into the throttle body by loosening the jubilee clip and removing pipe.

2. Remove the 4 x torx scres that secure the throttle body to the inlet manifold.

3. Remove power connector and withdraw the throttle body.

4. Clean with carb cleaner spray and an old rag (being very careful not to damage the butterfly valves).

5. Replace in reverse order.

[artscot79]

Coil changed. It is a vVery simple task.

1. Remove HT leads (remember the order and where each goes). Fortunately both the leads and the new (bosch) coil have numbering on them which is helpful.

2. Remove the 4 x torx screws.

3. Lift the coil up and withdraw enough to gain access to remove the power connector (very difficult to do while the coil is in place, easy when lifted out and turned upside down).

4. The coil pack is now out.

5. Re-fit in reverse order

(easy). :)

Took it for a short drive, the feels better and so far it has not stalled. No misfire through the driving range either. Still a very slight 'butterfly' sensation on the idle but not enough to make the revs change. This could be normal (before the problems developed I never really studied the idle in any great detail). Hopefully all good but I will monitor with care over the coming days.

I also took the throttle body off and cleaned it thoroughly while I was under there. Again very easy to do.

1.Remove the air intake pipe leading into the throttle body by loosening the jubilee clip and removing pipe.

2. Remove the 4 x torx scres that secure the throttle body to the inlet manifold.

3. Remove power connector and withdraw the throttle body.

4. Clean with carb cleaner spray and an old rag (being very careful not to damage the butterfly valves).

5. Replace in reverse order.

none of the fords idle perfectly due to the emission system low revs most idle 700 +/-30 rpm so 670 -730 is normal compare that to most petrols which idle at 800-850 usually 850 ford diesels idle at 800-850 whereas most others are 850-900 so the idle will always go up and down as the ecu tries to find the lowest possible emissions so i wouldnt worry much about that

[Pioneer]

none of the fords idle perfectly due to the emission system low revs most idle 700 +/-30 rpm so 670 -730 is normal compare that to most petrols which idle at 800-850 usually 850 ford diesels idle at 800-850 whereas most others are 850-900 so the idle will always go up and down as the ecu tries to find the lowest possible emissions so i wouldnt worry much about that

Thanks for this. You are spot on in what you say, it's idle is 700 or thereabouts with the odd fluctuation slightly above or below. So far it's all good but I must admit I'm still a little paranoid about it going wrong! Hopefully it'll remain fine and earn my confidence!! :)

[Paul mann]

Try this ....reduce gap on plugs to 1 mm ...worked for me... Seems a little known ford secret that the 1.3 gap is to big and after time causes failure in coil....worth a try and may cure your problem