AFN Issues: Troubleshooting and Solutions

Hello everyone,

"We had a friend install an AFN engine into a Caddy. Now, the problem is that the engine suddenly jerks violently, especially at idle. The rev counter on the Golf 3 dashboard is erratic, showing fluctuations of up to 300 RPM. However, the engine doesn't shake as much as you would expect from a 300 RPM difference. It runs smoother above 3000 RPM."
The ignition timing is sometimes more than 2.5 degrees advanced, but the control unit is injecting zero correction. Oh, and the power seems to be fully there, at least as far as I can tell, if it's running up to the 4th cylinder.

No error codes found in the control unit.

What I can rule out, as it has already been checked or replaced by us:

- Fuel injectors - brand new ones have been installed.
- LMM - shows values within the normal range.
- Fuel injection pump - replaced, but the same problem persists.
- Needle lifter - replaced, but the same problem persists.
- Timing is correct.
- Pistons in good condition, as they are only 200km old.
- Diesel filter is in like-new condition and has been drained.
- Timing belt in good condition, only 200km old.
- Relay 109 is activated.
- Valve for injection start --> see pump.

Not yet checked, or I don't know how to check it.
- Speed sensor (where is the sensor ring located, could it come loose?)
- ZMS (Could such an error occur if it breaks?)
- AGR
- Turbocharger

I'm at a loss, what can I do?

Deus Violentia wrote:

The ignition timing is partially more than 2.5 degrees advanced, however, the control unit 0 injects a correction amount

of

Quote:

ignition timing? What a terrible mistake in the diesel reservoir! Which specific sizes (MWB) are you referring to? ..... Oh, the performance is definitely there, or at least that's what I would say, if it goes up to the 4th winding

...... }What does "wickeln" mean?
If the MSG (Main System Board) is damaged, I would first install an original replacement.

Is it perhaps the engine from your other thread?

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Then the problem would be due to the incorrect injection amount from the oversized pump, which is not properly adjusted in the engine control unit (ECU).
The actual fuel injection amounts are significantly higher than what the engine control unit (ECU) believes they are, leading to excessive fuel being injected and causing jerking or hesitation.

Do you currently have multiple 'projects' or 'challenges' on your plate?

Best regards, Jochen.