VPN Disconnect: Troubleshooting & Solutions

Hello fellow DIY enthusiasts!
I recently got a trial...
"I'm having issues with my AFN engine that I installed in a T3 van. It has slight misfires, more like a hesitation, but only in the lower RPM range. It also smokes a bit when it's misfiring. The error code in the diagnostic memory is 00513: "Engine speed sensor (G28) - implausible signal." I've already replaced the sensor multiple times and rewired the cable, but there's no improvement. Often, it just stalls and then becomes difficult to start."
I noticed that there were a lot of air bubbles in the intake hose. It runs perfectly fine when stationary, but as soon as I slightly adjust the throttle, it starts to stutter. It also revs up well.
I once read out the measurement data blocks. I've written down below what was noticeable.

MWB 0
The injection start time varies between 38 and 79 units when the system is at a standstill.
"The fuel injection amount is only 56 at full load."
Coolant temperature with a cold engine: 145 degrees.
10 kg of air intake at idle, 145 kg at full load, 191 kg.

MWB 2
Air mass: 535 mg/h at idle, 625 mg/h at full load.

MWB 8
3 Injection starts at 0.65-1.75 degrees ATDC (After Top Dead Center), full load at 14.73 degrees ATDC.

Does anyone have any idea where the problem lies?

Hello,

You might have two problems.
- Poor fuel supply, foam/air bubbles in the hose leading to the ESP (Electronic Stability Program).
- Donor G28

The latter is likely the bigger problem. Therefore, carefully inspect all the wiring from the sensor to the engine control unit for any signs of chafing or damage caused by rodents, as well as all the connectors. An auto scan would have been helpful.
If things go wrong, the encoder wheel for G28 might also be causing a problem, or the distance from the sensor might not be correct.

Most common causes of air in the fuel system for this engine are: diesel filter, anti-vibration mount, and oil leak lines from the exhaust gas recirculation (EGR) system.

Best regards, Rainer.

Thank you for the response.

Regarding the fuel supply, I can say that I got a new tank installed about 500-600 km before this problem occurred. So, at first, I thought it might be related to the tank, but when I try running the engine using fuel from a canister, I experience the same issue.

The engine used to start much better before. Now, I have to use starting fluid again. I've already replaced the fuel filter and the fuel pump.

I have replaced the G28 multiple times and temporarily rerouted the three cables.

I remember once when the engine wouldn't start. I removed the G 28, cleaned it, and then the engine started. However, I eventually had the same problem again.

That thing about cleaning and then [something else] only worked once.
At first glance, the feeder wheel looks quite good. I want to take another look at it with the camera.

Could you perhaps tell me what voltage the G28 is operated at? I'm also wondering if the control unit might be faulty.
I still suspect the pump might be the problem.

Best regards.

Hello,

Please do not use starting fluid (it can permanently damage the engine). Instead of repeatedly trying different things, please just diagnose the problem and fix it.

Why don't you write whether the air bubbles/foam in the hose leading to the catalytic converter have been fixed yet?
Finish one construction site before starting another.

The LMM actual value is also too low, but that's a different issue and can be addressed later.

Your problem seems to be related to the G28 error and the engine shutting off. First of all, the motor needs to be running continuously; it's only turned off using the ignition key.

So, is the air leak in the fuel supply now fixed?

With a G28 error, there are several possible causes, the worst of which would be defective crankshaft bearings or starting discs, causing the encoder disc to move to an incorrect position relative to the G28.
Then check the G28 wiring (since the sensor is new), or any other wiring that might be causing short circuits, interruptions, or power supply problems.

If it doesn't start, can you access the engine control unit (ECU) for diagnostics? If not, there might be a problem with the power supply to the ECU. Search for "Relay 109" in this forum. Temporary power interruptions can cause seemingly random errors to be stored.

Best regards, Rainer.