VWDiesel.net The IDI, TDI, and mTDI source.

Engine Specific Info and Questions => IDI Engine => Topic started by: derekp on October 28, 2008, 12:23:52 pm

Title: fuel line check valve - whats its real purpose?
Post by: derekp on October 28, 2008, 12:23:52 pm

In my 92 eco jetta there was a check valve back near the water separator. Its a small black plastic bodied thing. It also happened to be the major reason why I pulled 5 inches of vacuum at idle.

Its not in the car at the moment - I'm having trouble finding a new one.

But I'd really like to know its full purpose.
Is it:
1. a federal safety standard thing (car rolls over, fuel doesnt come out all over)
or
2. to prevent drainback to water separator when car is shut off?

Can anyone provide some info on this nasty little culprit?
also any leads on where to get one.
VOA claims "out of country back order" yet they also cant find it in their picture book of parts.

thanks !

Title: fuel line check valve - whats its real purpose?
Post by: Quantum TD on October 28, 2008, 01:39:30 pm

It's option #2. I'm sure you could live without it. It just makes starting easier when the pump starts sucking air due to bad seals. The Rabbits never had them, so I'm sure you could live without it.

If you decide to live without it, and your pump is tired, you may have to crank more in the morning to get her started.

Title: fuel line check valve - whats its real purpose?
Post by: the caveman on October 28, 2008, 01:42:05 pm

We used to take them on cars that had hard starting s issues when it was very cold and we couldn't find any of the obvious problems. Had no effect as far as we could tell, except POSSIBLY slightly longer cranking when very hot.

Title: fuel line check valve - whats its real purpose?
Post by: andy2 on October 29, 2008, 06:47:26 pm

I remove the supply check valve to get more fuel flow it sure helps with modded engines.My Jetta TDI and my dads passat no longer have them.