Just Trying to Get Gas

And the dumb nozzle keeps clicking off. If I fill very slowly, it helps, but still clicks off before it's filled, and I have to re-start filling 10x or more to get it filled. I want to blame the station pump, but then I try with my other (German) cars, and it fills fine. I can't figure out what is it about the fill neck that causes the problem. Then I blame the evap system on the car, but it seems to be in order (that is, the two way valve pressures are in order).

I've done some studying of the vapor recovery nozzle function, but haven't figured anything out of value yet.

 

75 308 GT4 which has a very large unrestricted filler neck. So large and open that you can see the fuel splash back into the neck when it is truly filled.

What I came across on Google is below:

(And from this, still - nothing obvious. I can't figure if flow is too restricted - or too unrestricted?? These nozzles are designed for all cars, carbs, injected etc so I'd think it would be something simple).

Thanks.





Nozzle not Pumping Fuel

The reason that a nozzle will not pump fuel can be determined by
several methods, which are:
Make sure the breakaway valve is not pulled apart. If the breakaway is disconnected, fuel will not get to the nozzle.
If the breakaway valve is together, inspect the nozzle. Due to the prepay feature in the nozzles, it will not engage unless there is pressure in the hose. This can be determined by holding up the plunger with your finger and opening the poppet valve by pulling on the lever. The fuel flow path is now open. If no fuel comes out the end of the spout, the nozzle is not the cause of this condition.
If hose pressure doesn’t allow nozzle engagement the lever or clip might not be adjusted correctly. This out of adjustment wouldn’t allow the plunger to move back to the lever reset position. Verify by pushing up on the plunger, and if the lever engages, either the clip or the end of the lever might need adjustment. To adjust the lever, the end should be bent up slightly. The clip can be adjusted by pressing up away from the latch plate, but be careful to not over adjust the clip because that would cause customer inconvenience.
If the nozzle and breakaway check out fine, then something inside the dispenser is at fault.

Nozzle Continuous Shut-Off Condition

The most common cause of continuous clicking off is due to the pressure activated prepay feature. Therefore, the pump must be turned on and authorized before hose pressure is applied. This hose pressure allows the nozzle to open, otherwise the nozzle will continue to click off until the system is pressurized.

Premature shutoff occurs when the fuel tank is not full and the nozzle keeps clicking off. This is usually due to the automobile fill pipe configuration and/or high flow rates that causes fuel to splash on the sensing shutoff port in the spout. The nozzle should be moved around to find an optimum dispensing orientation and/or the flow rate should be decreased by setting the nozzle in a lower notch. Note, some automobiles are difficult to fill no matter how the nozzle is orientated or at what flow rate.

If the above problem persists, dispense fuel into a bucket and if the problem continues, most likely foreign debris has clogged the automatic shut off air path and the nozzle may need to be replaced.

 

FWIW: I have this problem too to a small degree. Because of the click-off problem, I've left the key on to watch the gage while filling. After a challenging effort to get gas in, I see gas sloshing in the neck of the GT4, and the gage is just about full. I give it another click or two which is about a quart I guess, and the gage just tips to the top line.

With the AMG, or Honda, at the same station with the same pump, it fills "normal". It clicks off a little less if I fill at a glacial pace.

Also, I've tried holding the hood off the filler neck to see if venting makes a difference, and it still clicks off - also, the smell of fuel sucks!

I do agree that having it not shut off is worse.

 

I'm in good company! Now a Daytona - like a GT4 (I promise I'll only make a few comparisons) is carbureted, and has a similar evaporative system. My point is all the components that -I think- affect fueling are the same. There's the "Two-Way Valve" which maintains only a tiny tank pressure to limit flow to the charcoal box, I wonder if flow rate across this valve can be a problem?? But when I pull back the hood during fueling as an experiment to help venting, it still clicks off, so that can's be it.

There isn't a "Roll Over Valve" on a '75 GT4, possibly newer ones?

Something must be out of wack, as the pump nozzles must be designed to accommodate this basic setup. Maybe the filler neck allows splashing back up on the nozzle?

 

Thank you for your help. Have you changed any part of the filler neck or charcoal canister which solved the problem?

 

Very good point. I would say I have different luck at different stations. What is particularly troublesome is again the German cars filling smoothly and not the GT4. The pump might be sensitive, but it would be nice if some widget in the fuel system could be addressed and have the problem be solved.