AIFO Iveco 8061 Engine Stalling / Rough Running

Hello everyone,

I could really use your help.

I'm having a problem with a diesel engine. So far, I've checked the injectors, and they are okay. The compression is between 18 and 22 bar on all cylinders, which is within the tolerance range. The next step would be to take the fuel injection pump to Bosch Service for inspection. Here are two videos showing the problem. Video 2 shows the faulty engine, and video 1 is for comparison with a working one.

Engine manufacturer: AIFO Iveco.
Model: 8061 SM Turbo.
Power output: 165 hp.
2-stroke or 4-stroke diesel engine, manufactured before 1980.
Number of cylinders: 6.
Engine serial number: 768701.

What are your thoughts on this?

Sure, here's the translation:

"Thank you in advance."
Christian.

Hi there,

What is the injection timing?
Do the exhaust fumes smell like unburned diesel?

Regards,
Adrian.

Apparently, only one cylinder is malfunctioning. Therefore, it can't be an issue with the injection timing.

What is the valve actuation mechanism like?
Camshaft worn out, rocker arm bent, adjustment screw came loose, pushrod bent?

And yes, even if something is missing on the output side, it still has excellent compression.

I once had an engine where the exhaust camshaft was almost completely worn out, and it sounded exactly like that.

Best regards, Christian.

Hello.

Keep the engine running and then, one by one, loosen the union nut of the fuel injector line for each cylinder.
In the affected cylinder, no difference should be noticeable, while the performance of the other cylinders will continue to deteriorate. This way, you can identify the problematic cylinder.
Now you can try swapping the nozzles to see if the problem moves along with them.

What type of fuel injection pump does this engine have?
It is apparently available with both a series pump and a distribution pump.

There's another way to check the check valves of the common rail system; sometimes the springs break. These valves are found in both types of pump designs and are located in the connector where the injection line is attached to the pump.
You can do that yourself; you don't need a Bosch service for it.

Regards,
Mpire

"Good idea, it's a Bosch PES 6A inline fuel pump. If a spring were broken, would I get too much or too little diesel to the corresponding cylinder? I tried to open the lines, but the result isn't clear to me. Cylinders 1-5 run slightly worse, and cylinder 6 is running very unevenly. I can't make sense of that..."

chris3333 wrote:

Good idea, it's a Bosch PES 6A inline fuel injection pump. If a spring were broken, would I get too much or too little diesel for the corresponding cylinder?

You're getting something less than what you should, and it's arriving much too late, which could explain the blue smoke.



Mpire.

Mpire wrote:

You're getting something less than what you should, and it's arriving much too late, which could explain the blue smoke. Mpire

Could this also lead to the type of misfires that can be heard in the video? In my opinion, the blue smoke is normal in these generations of engines as long as they are cold. Then, some engine oil is burned until the pistons reach their correct size due to warming up. This is also the case with DAF engines from the 1970s.

Thank you for your information. A pre-chamber has burned out.

Best regards to everyone!

Christian.

Thank you for the feedback .

Good luck with the repair.


Regards,
Mpire