Non return valve for fuel line

[DataflowDesign]

HI all

 

Am looking to fit a non-return valve before the fuel filter on my 2008 VRS PD170.  Can anyone tell me which is the fuel line incoming from the fuel tank to the fuel filter please.

 

Thank you

[SuperbTWM]

4 hours ago, DataflowDesign said:

HI all

 

Am looking to fit a non-return valve before the fuel filter on my 2008 VRS PD170.  Can anyone tell me which is the fuel line incoming from the fuel tank to the fuel filter please.

 

Thank you

 

Can I ask why?

[DataflowDesign]

Sure.  Just bought the VRS PD170 10 days back.  starts fine every time during the day except when it has been left switched off overnight.

 

If left overnight then we have a failed start once, sometimes twice.  Once she does fire she idles.  This morning I waited for about 15 seconds with ignition on and after the glow plug light had gone out then she started fine.  

 

Had a similar problem on a golf pd130.  replacing the non-return valve sorted it. Also on an older Landcruiser.  It such a cheap easy thing to do and I was planning on it for peace of mind even if we did not have this fault to track down.

 

If it does not fix it then ill look deeper into the problem.  Only fault code now with VCDS is with the ignition switch - which could be playing a part, except it is only after sitting overnight.  

 

If no one knows which pipe I will disconnect each and see which one has fuel coming from it with the ignition on.  Am asking to  simply save a bit of time and mess at my end. Cheers

[SuperbTWM]

Have you made sure all the hoses are tight on the tandem pump and where the lines go from flexible to hard lines in the engine bay, these can sometimes allow air in the system which allow the lines to drain back overnight. I've had fun with these type of fuel issues before and despite changing pumps and components I have always found it to be a simple loose hose or a seal causing the issue. Fitting an NRV may fix the issue but only by masking another problem

 

I can't say for certain which hose is the supply, if you had a picture of the pipes it may job my memory but like you say, it doesn't take much effort to find out. Something in the back of my mind thinks that the quick release connectors are a different colours to signify the supply and return maybe one is blue or has a blue mark on it for the supply?

 

 

Edited 29 September, 2018 by SuperbTWM

[DataflowDesign]

Great advice - thanks - ill go check now.

[DataflowDesign]

All pipes look good, and are tight.  Appreciate the advice. 

 

NRV should be here Monday.

 

Fuel pipes:  good memory, one yellow, one blue. I'll check the blue one when I get the NRV ready to fit.

[SuperbTWM]

No problem, its worth looking under the back seat and wiggling those lines as well to make sure they are fully 'home'

 

Hope you get it sorted.

[DataflowDesign]

Thanks. I'll go do that now. 

 

It'll get sorted - I'm not one to quit until it is right. Been messing with cars for nearly 40 years. Always good to learn new things.

[BlackstarSolar]

Did you manage to sort this? I've got exactly the same problem on my 2006 Octavia vRS.

[DataflowDesign]

I fitted the NRV.  Problem persisted.  

 

I'm pretty certain now it is to do with the engine re-map done before I got the car.

 

If I start it with about 50% throttle on the first start of the day it starts fine. and is ok for the rest of the day.

 

Good luck with yours.

 

 

[BlackstarSolar]

20 hours ago, DataflowDesign said:

I'm pretty certain now it is to do with the engine re-map done before I got the car.

Mine has never been remapped so may not be related.

 

Have you ever had any other suggestions of things to check/try?

[DataflowDesign]

I would check:

 

Glow plug relay

 

Glow plugs

 

coolant temp sensor.

 

Just for good measure mine did the mis0-start twice tonight. This morning when it was -2 it started fine on 50% throttle.

[BlackstarSolar]

5 hours ago, DataflowDesign said:

I would check:

 

Glow plug relay

 

Glow plugs

 

coolant temp sensor.

Mine's the petrol so no glow plus or relay. Coolant temperature sensor changed 6 months ago to no effect :-(

[J.R.]

If its the same as the MK1 then I think that the anti-return valve is in the fuel level sender assembly, I made the mistake of swapping the hoses when refitting and whilst the fuel pump powerfull enough to suck fuel through the anti-return valve in the wrong direction it created such a vacuum that air was drawn in past the O ring on the push in T piece on the fuel filter, it coincided with a new filter and when I removed it and fitted the old one the vehicle ran OK so I blamed the filter, returned it and fitted a Bosch one, same problem!!! It would only seal againts the old filter.

 

Eventually other fuelling problems led me to my initial error, the pipes were coloured blue and black and I then wrote that beside the relevan fittings. Its a vet easy mistake to make and the problem may not manifect itself immediately, I reckon a lot of main dealers and garages will have done the same.

 

It may not be the same on the MK2 but if you or anyone else has ever worked on the tank sender then its something to check.

[DataflowDesign]

That’s a very interesting thought.  Thank you.