(T) Head gasket, piston ring or sticking valve problem?

Try disconnecting the air inlet pipe off the manifold (next to the EGR valve) and starting it from cold, wait till the smoke clears, stop it, leave it, start it again next day. If you don't have smoke, then it is coming in through the inlet pipework (ie from the turbo or breather / vapour trap pipes). If you have smoke, it is coming from inside the engine, i.e. piston rings, valve guide seal etc.

To be pedantic about I think you'll find the JTD115 doesn't have a waste gate in the excepted sense although I concede it uses a mechanism that accomplishes much the same task.

every turbo has a waste gate other wise the turbo would just spin faster and faster and then blow up

I like the idea but I have trouble to locate the pipe you mentioned.

On the other hand, I save 2 vapour recovery pipe on the top of the engine. I am puzzled about their function and design.

1). The red one in the font. Why does it directly get into the turbo intake? Oil vapour will get into the turbo and then to the intake directly....

2). Where is the blue vapour pipe goes to? I saw it get into the engine in back.

Thanks again in advance.

The JTD80 does indeed have a waste gate but not so the JTD115 which is fitted with a VGT (variable geometry turbo)



This the the actuator controlled directly by the overboost valve and you can just see the actuating rod (top middle). Notice the tube at the bottom which returns to the overboost valve (otherwise known as a VGT solenoid)

This directly controls the geometry of the blades on the turbo and therefore controls excessive boost in a much more efficient way than a waste gate.

Another question about my dying stilo...

I can reproduce the problem:

When start the car, turn the key to 'start' immediately without waiting for the engine check, glow plug indicator go off...etc. This cause my JTD engine unable to start up properly. Even after couple minutes, restart again with proper check done. It still unable to start... It just like a petrol engine without spark plug. There is no ignition. Eventually, after long wait and long keep starting it. It get back to normal.


Don't quite understand the reason. Any idea?

Forgot the diagram... Here it is.

Wow, thanks! However.... geometry of the blades on the turbo....

This is beyond my knowledge. Can you explain what exactly is that blade? I am quite interested to know these stuff.

If your JTD engine is cold then you should always allow time for the heater plugs (glow plugs) to warm the cylinders (so the fuel will ignite). This is the same for any diesel.


The large intake (about 8cms dia.) tubing that john55 refers to is towards the back and you need to remove it from what looks like a carburetor on the inlet manifold. It will be easier if you remove the engine cover first. It sounds like a good test to me so I'd do it but never drive with it like that as it's taking in completely unfiltered air.

The killer reply: Is the oil filter fully tightened? If not it causes a pressure leak and oil evaporates and spills out - but you will never notice anything apart from believing the engine drinking oil. Also ceck if the seal is moist or dried up. Or if there is an extra seal from an earlier change. If so, remove it as it will never tighten correctly.

Just trying with an extremely simple solution.

M.

Just want to post some updates for my sick JTD status and give a conclusion for this thread.

A friend's friend who work in gargage check my JTD. He said he's sure engine is good. No head gasket problem or piston ring issue. He believes it's electronic problem.

I wasn't very convinced with his diagnose because I done a computer check in FIAT dealer. Report shows nothing wrong. From my understanding, this computer check should rule out all the electronic problems.

He changed the MAF sensor for me and amazingly.... problem improves a lot! Not completely gone but much better.

Now, I don't trust computer check that much. My plan for now is:

Clean all the oil dirt around turbo and it's pipes. Hopefully this could find out the source of oil leak and narrow down the root cause. I'll reading all the relavent threads and will start a new thread to ask help soon.

Examiner will only report faults - not a sensor just being out of tolerance.

Don't forget you can go for a drive with Examiner connected and if configured correctly it will report actual MAF readings vs predicted readings.

A good technician should then be able to judge if a sensor is suspect.

The trouble is it's often cheaper to just change the part than pay for diagnosis.

You should have done that weeks ago