Hi hoping someone can help, my son owns a mk2 fabia 1.4 tdi which is refusing to start. 

Parked up one night and since then has just refused to start. 

Cranks over, so not the cam belt. 

Changed the battery just in case the other was on its way out and a lack of compression. 

Now I'm stuck, like I said it will crank over and on occasion has started but sounds lumpy and no response from accelerator. 

Any clues, ideas or common faults would be appreciated. 

Hi there, sorry to hear about you car troubles. I would not eliminate timing trouble just yet though as the belt may have skipped a tooth or two rather than snappinv meaning the engine would turn over but run horribly or not at all. To check the timing pull the timing covers off and see if the timing marks on the crank pully and camshaft pully line up, I they do then its probably not a timing issue. It may be worth buying a scan tool for the car as then you should be able to see if there are fault codes for things like injectors, glow plugs and maybe the fuel pump as if any of these are faulty it could cause issues starting. The last thing I can think of is (but please don't take this the wrong way) to make sure the car is not out of fuel and was not misfuelled.

I hope this is of some help to you and good luck finding the problem.

I would start with the big relay in the fuse box near your right knee. Not saying this is your problem, but very common failure. I've probably changed 6/7 in the last year or so.