1.6 petrol mk2 CMAX constant stalling
Discussion
Hi,
Wondered if anybody was familiar enough with ford petrol engines to guess what might be wrong with my car?
2011 1.6 petrol 100bhp Ford Cmax (mk2 Cmax, same engine, drivetrain etc as as a mk3 focus).
Main symptom:
It stalls... a lot.
Sat idling for a while, if you rev it a bit, then let off, sometimes it'll bog down then stall. If you rev it and lower the revs slowly it doesn't. Doesn't happen all the time, mostly when start stopping in traffic, but it does happen a lot. Weather makes no difference. Runs fine at higher revs, always restarts immediately.
Seems like idle control, but this has no idle control valve and is all regulated via the ECU.
No OBD2 codes stored.
Other symptoms (possibly a symptom of the dodgy idle control):
Even more stalling with the A/C on.
More frequent stalling with the heated windscreen etc on.
Bit of mild throttle lag.
Any suggestions on where to start?
Thanks in advance!
Wondered if anybody was familiar enough with ford petrol engines to guess what might be wrong with my car?
2011 1.6 petrol 100bhp Ford Cmax (mk2 Cmax, same engine, drivetrain etc as as a mk3 focus).
Main symptom:
It stalls... a lot.
Sat idling for a while, if you rev it a bit, then let off, sometimes it'll bog down then stall. If you rev it and lower the revs slowly it doesn't. Doesn't happen all the time, mostly when start stopping in traffic, but it does happen a lot. Weather makes no difference. Runs fine at higher revs, always restarts immediately.
Seems like idle control, but this has no idle control valve and is all regulated via the ECU.
No OBD2 codes stored.
Other symptoms (possibly a symptom of the dodgy idle control):
Even more stalling with the A/C on.
More frequent stalling with the heated windscreen etc on.
Bit of mild throttle lag.
Any suggestions on where to start?
Thanks in advance!
Are you 100% sure it doesn't have an idle control valve? If it's less responsive and struggles when additional load from the AC is added, it could fuel related or intake related. Fuel pump failing? Throttle body failing or not closing properly? Fuel filter blocked? Personally I'd check the throttle body first, see whether it's slightly sticking open meaning too much air is getting in which could result in it cutting out and feeling less responsive.
zedx19 said:
Are you 100% sure it doesn't have an idle control valve? If it's less responsive and struggles when additional load from the AC is added, it could fuel related or intake related. Fuel pump failing? Throttle body failing or not closing properly? Fuel filter blocked? Personally I'd check the throttle body first, see whether it's slightly sticking open meaning too much air is getting in which could result in it cutting out and feeling less responsive.
Hi, I'm 90% sure it doesn't have an ICV. By that I mean I went looking for it in the inlet manifold and couldn't find it then google suggested there isn't one.Google also suggested there isn't a fuel filter, some sort of lifetime filter as part of the pump (odd, but apparently my SV1000 has the same set up).
I assumed a dodgy pump/filter would be more noticeable at motorway speed rather than idle though?
I can check the throttle bodies. IIRC from previous fords they were teflon coated and looked spotless, see if this one is the same, cheers!
One other thing that has come up in my frantic googling is a PCM update from ford. No experience of how much of a pita it is to get done?
Is there a modern car that's not fly by wire?
I doubt the PCM update will cure it, especially if the cars been fine all it's life until recently. It's worth checking all the inlet bits and bobs, throttle body, inlet manifold bolts are tight, inlet manifold gasket hasn't got a hole in it, no holes in air filter hosing or box etc. I had a Mazda 5 petrol which had a similar fault, would drive fine but idle terrible and cut out, turned out it the inlet manifold gasket was knackered and letting in excess air. New gasket and all was sorted, it also resulted in an improvement in throttle response and MPG.
I doubt the PCM update will cure it, especially if the cars been fine all it's life until recently. It's worth checking all the inlet bits and bobs, throttle body, inlet manifold bolts are tight, inlet manifold gasket hasn't got a hole in it, no holes in air filter hosing or box etc. I had a Mazda 5 petrol which had a similar fault, would drive fine but idle terrible and cut out, turned out it the inlet manifold gasket was knackered and letting in excess air. New gasket and all was sorted, it also resulted in an improvement in throttle response and MPG.
Clean or check the throttle butterfly and housing for heavy carbon deposits 
they will only self adapt over a long period but to a point 
then you will get what you describe , the software or adaption values were not made to cater for restrictions like these , also check the PCV hosing from valve to inlet manifold these are prone to perishing/splitting/collapsing causing un-metered air leaks easily detected with a shot of brake/carb cleaner etc
they will only self adapt over a long period but to a point then you will get what you describe , the software or adaption values were not made to cater for restrictions like these , also check the PCV hosing from valve to inlet manifold these are prone to perishing/splitting/collapsing causing un-metered air leaks easily detected with a shot of brake/carb cleaner etc Edited by Sardonicus on Friday 5th October 10:26
zedx19 said:
Is there a modern car that's not fly by wire?
I doubt the PCM update will cure it, especially if the cars been fine all it's life until recently. It's worth checking all the inlet bits and bobs, throttle body, inlet manifold bolts are tight, inlet manifold gasket hasn't got a hole in it, no holes in air filter hosing or box etc. I had a Mazda 5 petrol which had a similar fault, would drive fine but idle terrible and cut out, turned out it the inlet manifold gasket was knackered and letting in excess air. New gasket and all was sorted, it also resulted in an improvement in throttle response and MPG.
Thanks, will check tonight.I doubt the PCM update will cure it, especially if the cars been fine all it's life until recently. It's worth checking all the inlet bits and bobs, throttle body, inlet manifold bolts are tight, inlet manifold gasket hasn't got a hole in it, no holes in air filter hosing or box etc. I had a Mazda 5 petrol which had a similar fault, would drive fine but idle terrible and cut out, turned out it the inlet manifold gasket was knackered and letting in excess air. New gasket and all was sorted, it also resulted in an improvement in throttle response and MPG.
Sardonicus said:
Clean or check the throttle butterfly and housing for heavy carbon deposits they will only self adapt over a long period but to a point then you will get what you describe , the software or adaption values were not made to cater for restrictions like these , also check the PCV hosing from valve to inlet manifold these are prone to perishing/splitting/collapsing causing un-metered air leaks easily detected with a shot of brake/carb cleaner etc
Thanks! they will only self adapt over a long period but to a point then you will get what you describe , the software or adaption values were not made to cater for restrictions like these , also check the PCV hosing from valve to inlet manifold these are prone to perishing/splitting/collapsing causing un-metered air leaks easily detected with a shot of brake/carb cleaner etc Edited by Sardonicus on Friday 5th October 10:26
Sorry, yes it is drive by wire.
So, it's been doing this for about 9 months, getting a bit worse with time. Today, first time ever it didn't start. Possible its unrelated and my wife fudged it and flooded it as it started up after a minute wait. Turned over but didn't catch.
Anyway, I pulled the air duct off the throttle body, looked fairly clean inside and on the butterfly valve but gave it a wipe out anyway. Didn't seem to be sticking.
I checked all the hoses I could see for splits etc and they looked ok, no signs of splits. I sprayed brake cleaner around various parts of the inlet manifold and the idle stayed constant.
Probably worth pointing out that it doesn't hunt for revs, runs perfectly higher in the range and it is only occasionally that it stalls after giving it light revs, maybe every 1/15 times. if it doesn't stall then it revs up and drops back down calmly to normal idle rpm.
The pcm update I got from this thread, not sure why it would suddenly stop working ok though:
https://www.fordownersclub.com/forums/topic/81537-...
There are one or two similar threads elsewhere on the net.
So, it's been doing this for about 9 months, getting a bit worse with time. Today, first time ever it didn't start. Possible its unrelated and my wife fudged it and flooded it as it started up after a minute wait. Turned over but didn't catch.
Anyway, I pulled the air duct off the throttle body, looked fairly clean inside and on the butterfly valve but gave it a wipe out anyway. Didn't seem to be sticking.
I checked all the hoses I could see for splits etc and they looked ok, no signs of splits. I sprayed brake cleaner around various parts of the inlet manifold and the idle stayed constant.
Probably worth pointing out that it doesn't hunt for revs, runs perfectly higher in the range and it is only occasionally that it stalls after giving it light revs, maybe every 1/15 times. if it doesn't stall then it revs up and drops back down calmly to normal idle rpm.
The pcm update I got from this thread, not sure why it would suddenly stop working ok though:
https://www.fordownersclub.com/forums/topic/81537-...
There are one or two similar threads elsewhere on the net.
Edited by Maelstrom666 on Friday 5th October 21:15
rondema said:
Hi!
Having the exact same issues with a 2011 1.6 petrol C-MAX
Like stop/start but without the start ??
Did you ever manage to resolve the issue?
Thanks
Ben
Its an old thread and don't know if the OP got the car fixed in the end but my immediate thought was a failing crankshaft position sensor....Maybe? Having the exact same issues with a 2011 1.6 petrol C-MAX
Like stop/start but without the start ??
Did you ever manage to resolve the issue?
Thanks
Ben
Edited by rondema on Sunday 10th April 16:43
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