EVAPS, fuel tank, anti trickle fill valve

A posting quoting the Discovery Workshop manual's description of the anti-trickle fill valve. Could this valve's malfunction prevent filling the tank?

...from the Workshop manual...
A vent line flow restrictor known as an anti-trickle fill valve is fitted to the filler pipe in the line between the tank and EVAP canister. The function of this valve is to prevent overfilling the tank by trickling fuel in, thereby preserving the vapour space in the tank to allow for fuel expansion during hot weather.

The valve achieves this by blocking the vent line during the fuel filling process. The valve is operated by the action of inserting the filler gun so that when the fuel in the tank reaches the level of the filling breather, flow cut off occurs due to fuel filling the filler pipe.

Fuel level sensor

The fuel level sensor (fuel gauge sensor) on the Discovery died (symptom: fuel guage reads absolutely empty, yellow "low fuel" light on). The sensor works by varying resistance with the level of the float, low resistance at full tank and high resistance (something like 250 ohms) at empty tank. In the picture below, the arm extending to the lower left is the float arm, and attached to it you can see the wiper of the variable resistor. Note the small wire extending down across the front face of the wiper arm, which had rotted and broken so that the circuit was open. The open circuit made the fuel gauge read empty.

I fixed the sender, for now anyway, using a thin piece of copper wire I obtained by sacrificing a pair of headphones. Now, when the tank is absolutely full, the fuel gauge needle is about 1/2 a needle width above the full line.

Note that, when testing the sensor with the pump installed in the tank, the green/black and black wires lead to the sensor. However, since there are two black wires (ground), one for the sensor and one for the pump motor, and because these ground wires are not common, i.e., not tied together, within the pump, you need to check the correct black wire. On this pump, looking at the 4-pin multiplug socket from the top, with the wiring harness disconnected, the correct black wire is the one adjacent side-to-side, not top-to-bottom (where "top" is where the latch on the harness connector is, towards the front of the car).

Fuel filler neck part no, $

Atlantic British tells me that the part no. for the filler neck is ESR3707, and the cost is $444.95 (!!!). I'm not sure exactly what is included in that price/part no., i.e., does it include the anti-trickle fuel valve?

ESR 3707 does not come up in Google, which is a bad sign.

Link: '98 Disco (US) fuel filler neck problem link

Posted on May 14, 2001 at http://www.landroverexchange.com/forum/messages/11991.html

Prior to the recall notice last year, I was having problems filling the gas tank. About the first 5-6 gallons went in just fine, then the remaining 10-15 gallons took forever to get into the tank. The gas would constantly fill up to the rim of the filler neck, then you waited a few seconds, then pumped another 1/4 gallon or so, then waited........

The tank filled just fine after the recall notice work was done last September, but last week, started again.

Link: 2001 Discovery fuel filling problem

Posted at: http://en.allexperts.com/q/Land-Rover-Repair-1470/Fueling.htm

Expert: John McInnis
Date: 7/17/2005
Subject: Fueling up

Question
I have a 2001 disco2 4.0 litre v8 when trying to fill the gas tank the gas backs up in the filler neck and shuts off the filler nozzle it does this even when filling slowly by hand i cannot even fill by locking the nozzle i must do this by hand
i have the NAS filler neck this is a really annoying is there a modification that can be done to the filler neck or a replacement neck
any info on this will be greatly appreciated

thanks bruce

Answer
Hi Bruce,

I've heard of this problem before. It has to be a pressurization problem. There is an air vent tube that allows air to pass as you are filling your tank. If this tube is crimped or damaged it could restrict the air flow and thus cause this problem with every fill-up.

One owner who had this problem, while under warranty, was so fustrated after at least 4 service calls that he insisted on having his fuel tank replaced. Seems to have solved the problem for him.

In your case, you may have to replace the filler neck assembly, perhaps the fault lies near the top and not within the tank. Otherwise, the tank will have to be replaced.

I wondered if the air vent tube could be tested...but since it deals with gas, I'd have an expert pressure test this for blockage.

Best of luck,

JohnMc

Link: 1999 Discovery fuel filling problem

Posted at: http://www.motorbeat.com/complaint/412653/

Complaint for Land Rover Discovery 1999

Complaint about FUEL SYSTEM, GASOLINE : STORAGE : TANK ASSEMBLY : FILLER PIPE AND CAP

Consumer Complaint:
CONSUMER NOTICED WHEN THE OUTSIDE TEMPERATURE IS HOT GASOLINE FILLER NECK DOES NOT ALLOW YOU TO PUT MORE THAN 2 GALLONS. DEALER NOTIFIED. *AK

Date of Incident:
20030710

Tried something new

I tried filling the Discovery's tank with the small pig-tail vent line disconnected, but the problem persisted. The line is easily detached (quick connect) when looking up at the tank underside kneeling down next to the fuel filler door.

Since disconnecting the line made no difference, it appears that the problem is with getting the fuel down the filler neck, rather than getting vapors out of the tank.

SPDT relay wiring

SPDT Automotive Relays

from: http://www.the12volt.com/relays/relays.asp

SPDT Relay : (Single Pole Double Throw Relay) an electromagnetic switch, consist of a coil (terminals 85 & 86), 1 common terminal (30), 1 normally closed terminal (87a), and one normally open terminal (87).

When the coil of the relay is at rest (not energized), the common terminal (30) and the normally closed terminal (87a) have continuity. When the coil is energized, the common terminal (30) and the normally open terminal (87) have continuity.

The diagram below center shows the relay at rest, with the coil not energized. The diagram below right shows the relay with the coil energized. As you can see the coil is an electromagnet that causes the arm that is always connected to the common (30) to pivot when energized whereby contact is broken from the normally closed terminal (87a) and made with the normally open terminal (87).

When energizing the coil of a relay, polarity of the coil does not matter unless there is a diode across the coil. If a diode is not present, you may attach positive voltage to either terminal of the coil and negative voltage to the other, otherwise you must connect positive to the side of the coil that the cathode side (side with stripe) of the diode is connected and negative to side of the coil that the anode side of the diode is connected.

Troubleshooting the Skype CIT400 iPhone

tried setting the CIT400 to NOT autonegotiate the ethernet connection speed (only option is to force 10M speed). This seems to have made things better.

Cliod PMP

To convert videos from YouTube to play on the Cliod, use Zamzar:

http://www.zamzar.com/url/

Select the file format mp4 (others may work, but I haven't tried them).  Once the video is converted, you will get an email with a link to download the mp4 file.  Copy it to the Cliod and you're done.