Technical Ducato 2.3 2017 black smoke and knocking on quick revs

[ltz]

Just purchased an auction sale ducato with engine problem description. black smoke / knocking sound. 180000 km manufactured 2016. Motor code F1AGL411D. Sounds great on idle. When revving up engine carefully it does not make any sound and less black smoke. When revving it up quickly there are wall painting amounts of black smoke and a knocking sound.

Clues
First thing i did was to clear a few codes to see if they pop up again, they havent. (P2244,p0238,p0236, p242e, p0547, p1248).
Changed fuel filter and there was some misshap with fuel assembly so I could se alot of dirt in the old filter.
Started it up after the fuel filter change and same engine behaviour. lots of smoke when revving and knocking sounds when revving quickly.
I can move the EGR valve manually (the one closes to the hood lock). The pipe leading up to it is wet/very moist inside)

I believe the coolant have a few drips of oil in it. but when I checked the oil heat exchanger the coolant looked fine down there, so only some oil in the coolant bottle (i'm thinking someone filled oil in the wrong place? and absolutely not the other thing you think about with oil in there )

I believe some oil seems to be leaking near the oil filler cap.

Help!
What should I inspect next? perhaps dismantle the egr manifold? turbo? Should any sensor malfunctioning around there give me new error codes if broken?

 

[ltz]

Was out trying to follow the flow and have another look at the egr. on my way there i noticed the pipes coming from the turbo was really greasy and filled with oil/debree. thinking its a turbo change coming along? could a malfunctioning turbo be the reason for the smoke + knocks? (cant really tell if I'm loosing power or not, its a 131hp on 3.5t. If I would guess the turbo is working/ doing something at least ) - will check for oil in the intercooler tomorrow. would not be surprised.

 

[ltz]

 

[Anthony489]

Hello Itz

Sorry to hear of your problems.

The "EGR Valve" at the front with the rubber air hose is the Throttle Body, which is one part of the EGR system. The true EGR valve is near the exhaust manifold at the back of the engine.

I think you may have a problem with excessive pressure in the crankcase. The excessive pressure is due to too much combustion gas getting past the piston rings ("blow by"). This oily vapour then travels through the fume rebreathing hoses into the inlet manifold, where it coats everything with black sludge. It also tries to push past the oil filler cap seal and out around the dipstick seal. If you remove the filler cap with the engine hot and running the pressure may be demonstrated.

The black smoke indicates excessive fuelling of one or more cylinders. This could be a faulty injector, which may not throw a code. Alternatively it could be engine oil travelling up the bore and being burnt in addition to the injected fuel. The knocking sound when the engine is under load (accelerating the mass of the flywheel) is worrying - any mechanical knock at crankshaft rate (one knock per revolution) could be a problem with a piston or piston rings.

You might be able to get the injectors removed (It is a dealer job for most people), and then use a borescope camera to inspect the piston tops and the state of the cylinder walls without removing the cylinder head. With the injectors removed a compression test would also be possible, which will tell you the state of the piston rings and valves.

You mention the turbo - if the oil seals are leaking, engine oil will enter the intake airstream and be burnt along with the fuel. I don't think it will cause knocking noises though, as it spins too fast even at idle. If you can get access without too much dismantling you could check for any play in the bearings - there shouldn't be any.

Assuming the vehicle has a DPF, it may have been damaged by the soot levels in the exhaust.

 

[ltz]

Thank you for a great reply!

A few followup questions:
- Isnt the EGR valve the thing in aluminium color in the left lower corner in the second image? (pictured without its top electronic motor ). hence located in the front on this engine?

- I drove it warm and then checked the oil cap - not alot of air? trying to visualize it in this video:



- Here are some videos on the knocking sounds



I'm thinking to pursue the injectors next, removal and control? would it provide me any information to do the test where I connect each injector return line to a canister to compare them? or to find one that sticks out?

 

[Anthony489]

Hello again.

Apologies, I have misled you about the throttle body. Looking more closely I see that your F1AGL411D engine code means that your vehicle was built to the Euro 6 standard, which came in about September 2016. Unlike earlier engines, the EGR system on these engines is quite complicated, as Fiat wanted to avoid the use of SCR technology ("Adblue"). There is both a High-Pressure (HP) and a Low Pressure (LP) EGR circuit. The HP EGR valve is in front of the engine, and the LP EGR valve is near the bulkhead and hard to see/get to. Both these EGR valves also have throttle valves. See the attached diagram edited by FredAstaire, one of the forum members. After 3 years Fiat abandoned this idea and now use SCR like everyone else.

You should be aware that this particular engine variant has a reputation for problems with the DPF failing, followed by sooting up of most of the EGR system. If the sooting is really bad, it can block the EGR filters, prevent the various flap valves from moving fully and block the small holes to sensors such as the Manifold Absolute Pressure (MAP) sensor. The incorrect pressures trigger multiple fault codes, which can send even experienced mechanics in the wrong direction, replacing parts but not getting to the root of the problem. There is a long running thread on this subject on this forum. Some believe that the Fiat ECU software has fundamental errors.

I have looked at your videos. The crankcase pressure with oil filler cap removed doesn't seem all that high (there is always some pressure, even on a healthy engine).

The knocking noise when snap revved is quite loud. When an engine is idling, there isn't much pressure in the cylinders. If you rev up slowly, the engine is lightly loaded (it's still only overcoming friction) so pressures are fairly low. If you snap the throttle pedal down, the engine is briefly loaded as it accelerates the mass of the flywheel. The fuel delivery will momentarily increase. This is when your noise is loudest, so it seems to be related to cylinder pressure, exhaust gas pressure or the amount of fuel being delivered by the injectors. It is hard to pinpoint where it is coming from, I can only suggest that you get an engine stethoscope and probe around. If you can borrow some "skilled engine mechanic ears" to go with it then even better !

My feeling is that this is a mechanical noise, and in the worst case could be wear/damage in one of the connecting rod bearings ("little end" and "big end") which unfortunately means an engine out and rebuild. Another possibility is that the cylinder head gasket has failed between 2 adjacent cylinders, but I think this is less likely as it would probably upset idling.

Most other moving parts of the engine (e.g. camshafts, valves, flywheel) will only make noises according to RPM, and are not affected by the load on the engine.

I feel that until you have identified the source of the loud noise, there is not much point in testing other parts of the engine such as the injector leak-off.

 

[ltz]

Wow another really fact packed reply. Thanks!

It seems I still haven't gotten to look at the rear EGR, the front one looked shiny new from previous owner so ill try reaching the rear one. Hoping I can reach the rear one from the top.

Since a few hours I manager to pop out the injectors. really nice that they got loose simple. I could see some sort of "flakes of soot" and moisture on three of them and the most right cylinder was instead covered in soot.
- Thinking of letting a diesel specialist test the injectors - or just clean them myself (depending on time) - see pictures. Could it be that the soot-one would give too much diesel at revs and make the soot situation?

will try to get ahold of inspection camera, but unsure what i should look for in the cylinders

So planned next steps:
- find rear egr and inspect/clean
- make someone test the injectors or clean myself.

 

[Anthony489]

Hi

You were lucky to get the injectors out easily, many people find the injectors and/or the clamp bolts seized. There is no obvious damage to the tips visible in the pictures. Remember to put them back in the same order, they are individually coded into the ECU. With the injectors out it is feasible to do a compression test or cylinder leak test with the right equipment. I suggested an inspection camera as it will tell you if there is scoring (scratching) on the cylinder walls due to broken piston rings. If compression is OK then the rings will be OK.

I don't think the rear EGR is accessible from the top, it must be accessed from underneath and there is some dismantling needed. I strongly suggest you read this thread: https://www.fiatforum.com/threads/d...ro-6-egr-changed-what-do-i-check-next.491167/ and look at some of the pictures. I know it is a very long thread to read if english isn't your first language, but it is all to do with your exact engine variant and other peoples experiences, especially of the fault codes and the EGR and DPF systems.

 

[ltz]

So.. An update.. and report on the fix of the knocking problem. Injectors were all bad. one in particular but none passed the basic Bosch injector tests. The soot and banging was caused by in particular one injector feeding too much diesel. Ordered four new ones, runs supersmooth.

Unfortunately a few hours later an exhaust valve broke in the engine Surely related but not the problem of the banging + black smoke as shown in the videos above. When lifting the head several rockers was not getting enough oil making them "grind" themself down in to the valve stems. The exhaust valve that broke was just the first out of several that would come next. After inspecting this head I'm looking for a new engine. Not worth changing all the rockers + many valves + more on an engine with 180000 km on it. Looks like several of the oil channels to the hydraulic lifters was clogged.