Hi

My wifes reported that a couple times that when driving our Ford CMax 1.6TDCi it has cut out on her.

I've since found that the car is cutting out completely whenever you reach about 4000rpm. The acceleration is a bit hesitant and lumpy in the 3700-4000rpm range and then at about 4000pm it completely cuts out. As the revs drop off it doesn't pick up, its completely stalled and you have to use the key to restart the car.

Strangely no warning lights come on the dash until the revs reach zero, so if you coast in gear after the cut out the dash give no indication that the car has cut out but there is no response fromt he accelerator.

After the cut out if you put it into neutral or put the clutch down then the revs drop to zero... i.e. its not gone into limp mode or anything like that.

I checked for fault codes but there aren't any!

Note that the problem is 100% reproducable. i.e. every time you hit 4000rpm it cuts out, except its onyl when under load. i.e. it doesn't do it if you just very up to 4000rpm in neutral.

Some other clues that may or may not be relevant:

1. The oil level seems a quite high (Last changed by Ford a few months ago)

2. The DPF had to be replaced a couple of months ago (It died just after the Ford service mentioned above)

Any ideas?

Is this a known\common problem for this engine?

Thanks in advance

Ben

I dont know much about diesels, but I have read of similar problems being caused by a dirty Fuel Filter. It may be that.

Thanks for your reply

I had thought that too (Or maybe a failing fuel pump) but isn't the throttle of a diesel control by fuel flow (As opposed to a petrol car that is controlled by airflow), and therefore if the flow was restricted (Due to a dirty fuel filter or failing fuel pump) then wouldn't that just prevent the car from accelerating any further, rather than actually cutting out?

I guess its not that simple with a turbo car as the fuel flow and airflow need to be in balance, so maybe with the fuel restricted the ECU detects that the mixture is way too lean and therefore cuts the power.... but if this were the case then I'd expect to see a fault code.

I guess I'll have to take it to the garage.

Thsnks

Ben

Did you manage to find the fault?

I have a focus with the 1.6 tdci with the exact symptoms you were seeing.

Thanks

Check fuel pressure

Sent from my iPhone using Ford OC

Hi Ben,

Did you manage to repair this Problem. I have exactly the same issue with my 1.6tdci 2008.

Your best place to look I'd the fuel filter and having it replaced.

Your best place to look I'd the fuel filter and having it replaced.

Hi James, did this today as I suspected the fuel system as well. Low and behold it's good again. But have had a list of issues with this car to repair.

Thanks for the reply.

Glad to be of service and you got a fixed car! Will keep an eye out for the other issues.