The only place for a coil spring is up Zebedee's
Joined: Dec 22 2018
Posts: 51

Dear All, I was wondering if someone could give me an in-depth guide and parts required to fitting a non return valve into my Diesel fuel system. When I leave my car standing for a while I'm struggling to start it. Good battery, new glow plugs but just not firing up. I've heard it mentioned before about doing this mod. Many thanks.

Joined: Aug 05 2019
Posts: 159

Is the in tank pump good? If so you shouldn't need a NRV.

However, any commercially available NRV can be spliced into the line between the tank and the FIP, the closer to the FIP the better.

Joined: Jan 16 2016
Posts: 431

I have heard of it being done, but I have not done it to my diesel. I don't see the point if there is no need for it.
It seems to be done to get around wear in the in tank pump as Marshall8hp says.
For diesel to run back into the tank it must be letting air in surely? Check the fuel filter gaskets/unions as well as the FIP.
Are there any bubbles showing in the clear pipe to the FIP when it has been standing for a bit?