Hello all,

This is my first post after reading many posts around the 'glow plug' light on my delightful 100,000 mile 2003 TDCi Mondeo. I love the car... when this light isn't on, I get 55 to the gallon and it is amazingly comfortable and safe - a great family car... I hate the car with this light on...

The first time this light came on, on a long run, and would not go away on restart, I took the car to a Ford garage and they told be the fault code was "Knock threshold reached on number 3 injector", so after the first recode (which cleared the error for about 5000 miles), when the error came up a second time (this time on "number 2 injector"), I bit the bullet and had all four injectors and the fuel pump reconditioned by a very reputable firm, at this time I also replaced the DM flywheel (which was filling my starter motor full of grindings) and the fuel filter. The filter was clear, as was the fuel pump, so my fears of rubbish coming through the fuel line were removed.

The glow plug light came up again one month ago, another 5000 or so miles on from the last time I had it recoded, "injector number 3 knock threshold reached". I took the car to a new dealership, who said it was likely a duff Injector Control Module. My previous Ford garage had never raised this possibility, I shuddered at the prospect of replacing this by throwing another £700 at the car, so just had it recoded again (I didn't believe the possibility it was the ICM regardless).

2000 miles on - the error light has just come on again. I have no doubt it is a "knock threshold reached" error code. I trust the injectors, and the fuel pump are okay (only being 10,000 miles old if that), so, some clues I have for you fine experts.

• When you try and start the car from cold when the glow plug light is on (viz, the car is in limp mode), it requires a lot of turning over before it starts. It belches out plenty of white smoke smelling of unburned diesel if you try and rev it. Eventually, the car starts on what feels like three cylinders, and when it is warm, it runs okay in limp mode (clearly no turbo etc), but it does go. It restarts from warm fine too. I can't help but think, if I can get the car to run right in limp mode, the problem will go away once the car is recoded.
• I did a "bleed off test" on the car AFTER having the injectors replaced, concerned one of the injectors had been compromised, the test came up fine, no injector appeared to be squirting. I have NOT done this when the car is in "Limp" mode, might the ICM have been masking the problem? I will be doing the bleed off test again now the car IS in "limp" mode.
• When removing and refitting the fuel pump (what a horrid job that was), I removed the manifold and the EGR valve, these were both 'gunked' up reasonably badly. I had no will to clean these out by the time the fuel pump was refitted. Could this be the reason for this error reoccurring? Air as oppose to Fuel?

Does anyone have any suggestions for me? Or a Ford guru who knows these cars well I could take it to? I don't mind spending money on the car so long as I can be reasonably sure it will sort the problem out. I am shocked at Fords lack of diagnostic skills in this, their attitude has been replace each bit, one at a time, until it starts to work, rather than identify the bit that is not performing its function, and just replace the busted bit. In addition to that, their advice has been thoroughly inconsistent.

Any help or advise you can give will be gratefully received.

Best regards,

Mark