1.8 Tdci 2006 Focus - Limp Mode / Glow Plugs

[rg1642]

Hi,

Although I have fixed this problem it leaves me still wanting answers why it happened.

For no apparent reason my Focus just stopped reving past 3K and lost power. It also came up with 'Engine Systems Fault'. Noithing else wrong with the car and no fault codes present.

I trolled the forums and came up with 3 possible fixes based on what was written. 1 was the fuel filter and 2 the glow plugs. 3 was the wastegate actuator but I didnt get that far.

I changed the fuel filter with no difference so the proceeded to check my glow plugs. Every one was as dead as a door nail. 100% resistance and no current draw. Replaced all 4 and bingo back to normal.

Now I thought fault codes were there to alert you to problems, so why no code when all 4 plugs are dead? I also had no problems starting, even at freezing in the morning. How come? Would it not be easier to just let you know the plugs needed changing without the limp mode rubbish or are Ford just building in problems, without obvious fixes, just to make you go to the main dealer?

My main question is are there any underlying reasons why a diesel with 72K miles on it should burn out all it's plugs and should I be looking for something before they go again?

Russ

[jeebowhite]

OK so the reason for no alert light, is because the ECU doesnt look for a dip in resistance and then a return to full current, or at least not specifically. The problem is that as you start the car, the ECU would think that the engine was too cold, thus alerting you with a limp mode and "oh cack" light.

As for the reason for the failure, its possible that its due to water ingress. Given the rain we have had, and a workhorse with a number of hours under the glow plugs lights, the seals would be in a non too healthy state allowing more water in, the water would then kill them, and evaporate as the engine gets hot - potentially no signs of its fatal involvement.

[rg1642]

Thanks mate for that. Fair enough what you say but if it knows to say 'Engine Syatems fault' and put it into limp, why cant it just register a fault code for no current draw to plug. I know its a lot more spphisticated to my tractor but if the plugs all broke that would not start. The car starts and runs fine glow plugs working or not but just gives a generic warning and limp mode. Surely there should be a better way of indicating the fault. Or am I being over picky?

[jeebowhite]

Not every nook and cranny has a sensor you see, so what happens is one part suffers with no sensor. The next sensor in the sequence expects the number 1 or 2. All of a sudden, the number 999 comes back to the ECU, the ECU knows that the sensor returning 999 will only ever return errors 1 - 10, therefore it doesnt lodge the fault as being with that sensor, instead it cacks itself, an unknown error has occurred, it doesn't know where the problem is (all sensors are giving an expected value, but this one isnt giving an expected error message, but a wacky one! so it throws the EML on, panics and starts to hobble to make sure you dont break the unknown problem.

Then you get it to ford, who whisper quietly into its ear, charge you a bomb for it, then it speaks some sort of weird ford code to the laptop monkey who then looks up in a book that the error has to be the plugs :P

[rg1642]

Cool :D

[Greg999]

I've recently had this, though it did ping fault code for glow plugs. But the limp mode is a bum steer, as there is no reason for engine to go into limp mode.

So it makes you look else where for no reason.

Typically main dealer way of stealing from you!