Hi Guys, got a couple of queries. (2001, Polo 6n2, 1.4 16v Petrol, AUB engine code)

 

1 - After turning the ignition on the fuel pump runs what seems an eternity, in reality its about 8 seconds. My Mk2 golf runs and pressurises in about 2 seconds. Is 8+ seconds normal?

 

2 - I cant seem to find any diagrams of the fuel system pipework. When changing the fuel pump I had the flow and return pipes going to the pump, but there were also two other pipes that were routed over the top of the pump, where do these goes. If anyone can point me to a schematic of the pipework that would be much appreciated.

 

3 - Is there a prescribed way to testing the fuel pressure, where to break in with the pressure gauge etc?

 

I am sure I have more questions, but this will do for a starter? 🫣

 

Cheers Kev

 

 

Hi,

 

1 - I guess its as you mentioned one or two seconds. And i also guess independent from any fuel pressure in the system, but i only know the 6N1 really good. Means I also can be wrong.

 

2 - The pics are from a late 6N1 which will be very similar to the 6N2 system.

 

back in 2023 i had the following issue on my 1996 6N1. when the car was still standing for hours the whole system pressure went down cos a tiny tiny crack on one of the both in-tank-fuelpump-fuelhoses let flow all fuel from the system back into the fueltank, so i had no pressure when turning on the ignition and starting immediately. i had to turn the ignition on several times to fill the whole system before starting, once the motor was running, it all worked. with turning on ignition on my 6N1, the fuelpump relay works always these one or two seconds the ecu tells the relay to work, independent from fuelpressure cos there is only the 3bar fuel-pressure regulator in the injectionrail, there is no sensor for taking the fuelpressure.... in the 6N1..... as i mentioned 6N2 is not my cup of tea.

 

My advise, change the fuelfilter and/or locate the fuelpump relay on the centralelectricbox and renew it, maybe the working contacts are "sticky".

Changing the relay is easier, the filter sits down, deep down under the polo above the rearaxle.

 

 

cheers

 

Christian

 

Thanks Christian. That picture with arrows and labels is exactly what I needed!!

 

I am getting my pressure tester checked out as when I connected it in-line as it enters the fuel rail (white-in) I was only getting about 1.5bar (getting gauge calibrated as not sure if the pressure is correct or tester is faulty), and didn't increase much with the engine running, nor did it move much when vacuum pipe removed on the pressure regulator. The car is a Polo Challenge car and although low mileage its had a pretty rough life so I decided to change the Fuel Pump, at the same time I replaced the Fuel Filter. The problem we are experiencing is that it wont start when hot. We come off a stage, go to service and while hot will not restart.

 

We have changed Fuel Pump, Fuel Filter, Fuel Pressure Regulator, Water Temperature Sensor.

 

Fuel Pump still runs for 8+ seconds with ignition on.

 

I would say after all these changes to the car, when it starts it does run much better and more responsive. I have not replaced the fuel pump relay..... yet!

 

Thanks again, much appreciated.