hello, recently bought a mk2 fabia estate 1.6 tdi cr105 2011 to use as a work horse cheap as its not running correctly. Its puffing white smoke out exhaust which stinks of unburnt fuel, is in limp mode and is misfiring. When you unplug the injectors one by one they all make it run worse apart from cylinder 4 which seems to make no differences and looks like number 4 is a brand new injector. So I removed 4 injectors from a good running 1.6 fabia and coded them in and it actually make it run worse so removed them again and coded back into the original car and they ran perfect so looks like its not a injector fault. Its also had what I think is the dpf removed (the first cat is there right after the turbo its the next part thats missing just after subframe) and must of been done recently as the pipe they welded in looks brand new. Its also had the new software updade as I checked and there is zero codes on car.

 

guessing the new injector and dpf removal was the last guy trying to find what the fault is but unsure if the dpf is mapped out and id of thought it'd of thrown a fault code up if its not. Any ideas what it could be or where to look next? il buy a 2nd hand dpf if I can get it running 

I think you should check the compression on number four.

I did, from memory the other 3 were around 140-160psi and number 4 was a little less at 130psi 

the glow plug from number 4 was soaked in diesel aswell when I removed, even when unplugged when running its still throwing smoke out, maybes I need to run it longer with 4 unplugged and see if the fuel in exhaust etc burns off and clears then it might point to it being a electric fault  

It's not electrical, that compression is far too low, particularly on number four which suggests valve damage.

They all sound low for a diesel but I am only basing that on my knowledge of petrol engine compressions both standard and tuned, I though diesels were much higher?

Edited 5 May, 20224 yr by J.R.

Compression readings		Pressure
New engine		2,5 ... 3.1 MPa (25.0 ... 31.0 bar)
Wear limit		1,9 MPa (19,0 bar)
Max. permissible difference between the cylinders		0,5 MPa (5,0 bar)

 

@J.R. yes diesel pressures are quite a bit higher  

Edited 5 May, 20224 yr by nige8021

That car has slipped it's timing and the pistons have tickled the valve heads, it's a head off job I'm afraid.

I'm not saying the vendor knew before selling it to you, but I think it's extremely likely.

thanks guys so looks like ill need to find a engine, I thought the compression was ok as they were all similar but far from a diesel expert as you can tell. just when I unplug number 4 it makes zero difference to the running id think it would still make a change to the engine note when unplugged even at that compression? too far gone to even fire?

4 minutes ago, Chris9292 said:

thanks guys so looks like ill need to find a engine, I thought the compression was ok as they were all similar but far from a diesel expert as you can tell. just when I unplug number 4 it makes zero difference to the running id think it would still make a change to the engine note when unplugged even at that compression? too far gone to even fire?

 

All that white smoke is unburnt fuel mist, hence the wet glow plug. Unfortunately I've seen it before, the valve heads will be slightly canted and not sealing properly, you could fit a complete secondhand cylinder head which is less work than a replacement engine and about half the cost in parts and labour.

Hi again, started pulling the head off and found the hot side of turbine on turbo has completely snapped off but isnt leaking oil so removed the downpipe and it fell out. Ive found a complete engine but the engine code is CAYK and mine is a CAYC, will it still be good to fit? looks the same but maybes internals are different or slightly different compression ratios or something? its from another fabia but from a 12 reg where mine is a 11

1 hour ago, Chris9292 said:

Hi again, started pulling the head off and found the hot side of turbine on turbo has completely snapped off but isnt leaking oil so removed the downpipe and it fell out. Ive found a complete engine but the engine code is CAYK and mine is a CAYC, will it still be good to fit? looks the same but maybes internals are different or slightly different compression ratios or something? its from another fabia but from a 12 reg where mine is a 11

 

Why not just throw another turbo on it and see if it fixes it?

 

I find it hard to believe the head is damaged as well as the turbo, is it possible you weren't able to measure the compression accurately?

17 minutes ago, sepulchrave said:

 

Why not just throw another turbo on it and see if it fixes it?

 

I find it hard to believe the head is damaged as well as the turbo, is it possible you weren't able to measure the compression accurately?

I would but im sick of wasting time on it plus the turbo looks awful to take off on car then on top il need to drop subframe and fit a dpf so Id rather just do everything in one go and slot dpf in before refitting engine instead of fitting a turbo to then realize its still missing etc

1 hour ago, sepulchrave said:

 

Why not just throw another turbo on it and see if it fixes it?

 

I find it hard to believe the head is damaged as well as the turbo, is it possible you weren't able to measure the compression accurately?

I did the compression twice on each cylinder so its defo correct