if it sounds like a tractor and is kicking lots of smoke out the rear as in unburned fuel then yes injector would sound right.
but injectors are a big cost and a big job. so its best to take out all other problems could be the maf as they only have a certain life. best way to do that is to have an obd2 reader and reseter and then dc maf and run for a few mins if it has got better then its maf if not then move onto next possible thing. cleaning the egr valve is a must if u own a diesel car so that would be next if i was doing it, try some fuel system cleaner after that. other thing is check the intercooler pipes one comes from turbo to intercooler and one goes intercooler to intake manifold they are prone to split and when split they will blow smoke out the exhaust and hiss a little. and being as your loosing air after your maf then you will be getting to much fuel in the air fuel mix.
hope this helps and good luck.
list of how long jobs will take.
maf 5 mins( will need a laptop, usb to obd2 cable and the free version of fiat ecuscan)
egr 15-45 mins ( sockets and spanners also lots of knuckle skin if its where mine is lol. cleaning fluid i use carb cleaner as it drys very fast)
intercooler pipes are a little fiddly you will need to get the front of the car in the air tho enough for you to get under it. 5 mins bottom pipe turbo to intercooler. top pipe takes a little longer as there are some plastic covers that need to come off and its also very fidley. i think its regular on them all to have intercooler in the front right corner just behind fog lights.
p.s. if you love alfa's and dont mind working on them and you find the fault early on then do the rest of the list as you might not only have one fault. or you might catch one at an early stage. pipes last about 45k miles ish or aslong as it takes them to perish.
Originally Posted by 105&Sprint_luvr
Hi all, I am an Alfa lover through and through... but know little about Diesel engines and seek advice. My wife has a 147 JTD and it has done 150,000 kms in about 3 years. At about 90,000 kms it started to get louder and louder (the typical diesel tap tap that was hardly audible when new is now almost truck like).
There is plenty of power the car is running brilliantly... but it is getting noisy... any suggestions?
Is it likely to be injectors... if so what are my options and is this a big job?