One finger over fuel pump nozzle hole prevents foam! Who knew?

Did the finger fuel-mod work for you? Please do not answer until you are sure...


  • Total voters
    85

NarfBLAST

Top Post Dawg
Joined
Mar 3, 2002
Location
Waterdown, Ontario, Canada
TDI
2001 Golf 5MT
I want to see clear fuel near the top of the filler neck every time so that I know exactly how much fuel I used on the last tank.

Also, personally, I don't like head on my beer.
 

Dean

Veteran Member
Joined
Jan 27, 2011
Location
Vancouver, BC
TDI
2005 Passat TDI(Sold)
Why did they even bother putting that hole in the nozzle in the first place?

Who wants foamed diesel?:confused:
 

pdreyfuss

Veteran Member
Joined
Mar 14, 2006
Location
Asheboro, NC
TDI
1999 Jetta
Why did they even bother putting that hole in the nozzle in the first place?

Who wants foamed diesel?:confused:
I think the hole must be a part of the system that makes the pump shut off, and the foam is probably part of the same. There does seem to be less foam when you cover the hole. I know that when I bought B100 from DFW Biodiesel, there was no foam and little-to-no auto-shutoff.
 

NarfBLAST

Top Post Dawg
Joined
Mar 3, 2002
Location
Waterdown, Ontario, Canada
TDI
2001 Golf 5MT
Here is an excellent explanation of how the hole works:

http://myg37.com/forums/engine-drivetrain-and-forced-induction/175764-car-wont-let-me-pump-gas.html


I borrowed the picture, but please visit the thread on the other forum above. I will sumarize below:

A vacuum is created in the "sensing port" (the little hole) by a venturi effect of the fuel passing by the venturi ring. Air is sucked in by the venturi effect thru the sensing port and gets mixed in with the fuel causing FOAM.

During normal fueling, fuel comes up, covers the small hole, stops the inrush of air and creates a vacuum that activates the auto-shut off.

*BUT*

if there is not enough fuel flow to create a venturi effect then not enough vacuum is created when you cover the hole to active the shut off valve. When the hole is covered there is no mixing of air and fuel therefore you get clear fuel.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Great picture. As stated, the trick to covering the sensing port is to pump slowly. If you get too carried away, the vacuum gets created and the auto-shutoff trips. On some pumps it is difficult or impossible to pump slowly enough to fool the auto-shutoff.

This trick still works fine for me on most of the pumps that I fill up at.
 

Frequent Flyer

Veteran Member
Joined
Oct 27, 2009
Location
Dallas, TX
TDI
2000 Jetta, 6m "The White Knight"
This trick has worked for me at any station that uses the OPW nozzles.
Ususaly shell has them. They are covered in a green jacket that has the letters OPW on the side (the nozzle manufacturer, I'm guessing)

The last time i couldnt get the stinky finger mod to work was when I used a black handle...

BTW, I love this trick! I use it every time, and I dont have to wait for any foam to settle!
 

Art van Law

Veteran Member
Joined
Dec 14, 2010
Location
PVD, RI
TDI
2013 JSW
Stinky Finger

I tried this mod for the first time today. I wore a medical glove. I was amazed how long it took. A UPS truck pulled in to the pump next 2me, slurped 38 gallons and was gone in the time it took me to put in 5 gallons. I didn't have a start/end time, but I'd estimate approx 15 minutes to instill 15.53 gal. Good thing we had warmer temps here today (and I hogged the pump during a relatively quiet time of day.) I wouldn't attempt this on a colder day...takes too long!

I'm thinkin that at the next fill up, I'll live w/ the foam.:D
 

Art van Law

Veteran Member
Joined
Dec 14, 2010
Location
PVD, RI
TDI
2013 JSW
Why do you run your tank that low?
nate:

Au contraire, "...that low?" I could have driven it about 50 more miles according to my guestimate...but I was near the cheapest diesel in the area.

My low fuel warning light came on at 678 miles on the tank. Per the owners manual, I then had a reserve of 1.9 gallons, correct? At a conservative 40mpg, I could have gone until 754 miles had elapsed. I actually filled at 698 miles on the tank and that represents my greatest range yet.

I'm looking fwd to changing over from snows to LRR tires, summer fuel blend, and potential entrance into the coveted 800 mile club. I wish;)
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
I tried this mod for the first time today. I wore a medical glove. I was amazed how long it took. A UPS truck pulled in to the pump next 2me, slurped 38 gallons and was gone in the time it took me to put in 5 gallons. I didn't have a start/end time, but I'd estimate approx 15 minutes to instill 15.53 gal. Good thing we had warmer temps here today (and I hogged the pump during a relatively quiet time of day.) I wouldn't attempt this on a colder day...takes too long!

I'm thinkin that at the next fill up, I'll live w/ the foam.:D
You only have to use the stinky finger trick for the last couple of gallons. Pump full speed until it does the auto shutoff and then do stinky finger until it's full.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
'Twas Whitedog.
Stumbling along and found this and I gotta say, Me? When did I say that? It's really funny because I was reading the thread that linked to this thread and I started wondering where I heard it. But reading further down, I see that i heard it from a lady of the female persuasion.
 

Mike_04GolfTDI

Top Post Dawg
Joined
Nov 19, 2003
Location
Richmond, BC, Canada
TDI
Mine: 2019 Golf R DSG, Wife's: 2015 Golf Comfortline TDI
To pump with no foam, you just hold the nozzle so it's pointing slightly upwards.

This means you can only hold it so it's just barely inside your filler hole.

I do it all the time for topping up.
 

Mike_04GolfTDI

Top Post Dawg
Joined
Nov 19, 2003
Location
Richmond, BC, Canada
TDI
Mine: 2019 Golf R DSG, Wife's: 2015 Golf Comfortline TDI
Point the nozzel slightly upwards? With the hole pointing down I assume? I will try this!
I don't know if the hole has anything to do with it. All I know is that if the fuel is coming out of the nozzle in a slightly upward direction, you don't get foam. I learned it somewhere on these forums...
 

NarfBLAST

Top Post Dawg
Joined
Mar 3, 2002
Location
Waterdown, Ontario, Canada
TDI
2001 Golf 5MT
With the nozzle pointing upwards I did not get foam! I did get dribble back along the nozzle. I tried a few more angles and with and without the nozzle touching the filler neck but always fuel was running back towards me. Too messy in my experience. I made a small puddle just inside my right rear tire where the filler opening drain is.
 
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