Pump Not Working After Sealing? Troubleshooting

Hello!
I had the pump sealed at Bosch. They found that the flow control valve is defective and that the pump has corrosion. Therefore, they could only run the test cycle partially.

The Bosch service technician said that the pump might not have been working properly before. (But it was, except for the jerking at partial load). When asked if it would work the same way after being sealed, he replied yes.

After I reinstalled the pump and wired everything up, it's not pumping any fuel. I loosened the fuel injector fittings to see if/when it would pump and start, but unfortunately, nothing comes out after repeated attempts. I think the pump should already be full of fuel at this point. There is also diesel coming from the inlet line when I suck on it. Unfortunately, I don't have a clear section of tubing in the fuel line from the tank.

There is power at the control line for the ESP, and all cables are connected.

My question is, what could be the reason why it's not dispensing fuel?
Otherwise, I will have to buy a new (used) pump to check if it pumps properly and whether it will work with it.

Thank you very much for your help!

Martin.

Did you fill the ESP with (filtered!) fuel before installation, or did you simply mount it empty?

Regards,
Guste.

Hi!
I just let it run, as it must have been filled for the test run at Bosch.
I'm going to pour some fuel from a raised container into the ESP system and then read the error codes using VAG-COM.
"If I find another hollow screw, I'll try using it, because I'm not really happy with this crimped solution on the OUT screw, but it shouldn't actually be the problem (OUT, not IN)."

I will get back to you when I have new information.
Martin.

Martinito wrote:

I just started them up, as they must have been filled for the test run at Bosch. I'm going to run some fuel from an elevated vessel into the ESP and then read the error codes using Vag Com.

"However, the volume indicator for the mixing chamber is clearly higher than the inflow and outflow levels, which suggests that it was likely completely empty. It's possible that Bosch completely drained it to avoid any mess during transport."

Playing the organ without proper fuel might have already damaged it. While the VP37 isn't as sensitive as the VP44, it's not designed to last forever, especially with prolonged use.

When priming a fuel system from a raised container, always use a filter. Remember that the fuel will later pass through nozzles with openings as small as 0.2mm. Even the smallest piece of debris will likely clog them.

Reading the error codes, as you suggested, might also shed some light on the problem.

Regards,
Guste.

I'm having the same problem; I think it might be related to FZP.

lothi7 wrote:

I'm having the same problem; I think it might be related to FZP.

What do you want to tell us?

With such minimal information, no one can help you, no matter how hard they try. Either take the time to describe all the relevant points you've worked on so far and the results, or you can't expect to receive any help.

Regards,
Guste.