Gas Leak?

[Fuco]

So this has started recently and I've been trying to isolate the problem.

It seems like my car is leaking a little bit of gas, but only after I fill up the tank all the way. After filling up the tank and going out to it the next morning I can smell the gas and there will a very small amount on the ground. The amount it leaks isn't even enough to register on the gauge because it still reads full. After that first initial leak, it doesn't leak at all, until I fill it up the next time.

Anybody run into this problem or knows what's going? I'm definitely taking it to the mechanic tomorrow, but if I can save the hassle and do it myself or save the hassle of having them take a few hours to find the problem I'd appreciate it.

[zkv476]

Did you ever change your fuel pump? I changed mine and didn't have the lock ring tightened enough afterwards (I was short a whopping full turn lol) and I had the exact symptoms, small leaking right after fill up.

[humfrz]

When you fill it, do you let the pump "click off" or do you keep trying to get more gas in the tank?

If you are "stuffing" the gas tank, the gas may be expanding as it heats up in your tank .... thus over powering the evap system and a bit is being forced out.... ??

I suggest you just fill to the first "click off" and call it full .....



humfrz

[spitfire481]

its usually the black fuel pump ring gasket thats pinched and causes a leak when the tank is full. been there done that

[continuecrushing]

In before car fires and you know who is mentioned...

[Sithspawn]

Originally Posted by Shutter

In before car fires and you know who is mentioned...

roflmao!

[sprintamx]

OK, I know, this is an old thread . . . But, was the problem ever diagnosed? I've now had two episodes of leakage after a fill up. Both times I simply let the gas pump automatically shut off with its built in cut-off mechanism with no additional "topping off."

Both occurrences left about a pint of gas in front of the left rear tire. This appears to be an area in and around the gas tank where the fuel lines and evap lines converge.

Wile a trip to the dealer is probably warranted, I'm wondering if any one has previously confirmed that a new fuel pump was not properly tightened down, or there was some leak in the evap system, etc.

Thanks.

[pgranberg11]

yea, i'm having the same issues here. ONLY when I do a complete fill up. No top off nothing. As soon as a park the car, I go to my rear left wheel look underneath and it slowly drips every few seconds.

what exactly is the problem?

[raytrix]

I'm having this same issue too. I do have an upgraded denso fuel pump and it's leaking exactly where you guys mentioned.

[zkv476]

Make sure the fuel lock ring is tightened down all the way. It's pretty tough to tighten. Mine did the same until I realized it was a whole thread too loose. Seemed tight until I checked and tried to tap it tighter. I'm assuming you guys with this issue have changed the fp? If not then it may be a warranty issue.

[TxFrs10]

The Fuel lock ring was the answer to my woes. I thought I tightened it down as hard as possible after initial install. When I went back to double check it was easy enough to turn by hand. Thanks zkv476!

[ztan]

For those of you who have changed the fuel pump, also check the gasket installation: there is an outer flange that points downward and the gasket should be inserted into the tank rim before the pump assembly is put in. If the pump + gasket are inserted together and squished down, the gasket flange is likely to flip and not seal.

[steve99]

a very small amount of silicone type lube on the gasket and lock ring will allow it to turn freely and not catch on the gasket

[sprintamx]

I finally decided that enough was enough and started tackling this issue. I tried working through a dealer, but that was an epic failure.

As a starting point, yes, I had a DW 65cc pump installed in combination with a JRSC, flex fuel kit and 700cc injectors to handle E85 duty.

After exposing the pump there certainly appeared to be a lot of fuel residue around the pump / lock ring area. There is a slight slope in the pump area towards the front of the tank, which could explain that if there is leaking through the pump seal / lock ring, why it would flow down in front of the driver's side rear wheel (that's the direction of the slope in the top of the tank, and the pump is located just in front of that wheel).

After a visual inspection, I couldn't find any evidence of leaks on the fuel or evap hoses and connections in the area, so the evidence suggested a pump seal issue. I removed the ring and pump canister. The gasket around the top of the canister had a very thin lip, flange, flap in the middle that looked like it had been folded over or "squished" unevenly, as well as partially torn away from the gasket. While its possible that I did that when removing the canister, I don't think so since I tried to be careful and certainly didn't "rip" the unit out of the tank.

Thanks to other members and DIY threads, I was able to get a part number for the gasket. The gasket is advertised as a "must replace" part with servicing. I do not think my was replaced with the DW pump install. Perhaps that flange is so weak that one installation (at the factory) is all that it can handle.

After confirming that the part was not on hand within 50 miles (including World PAC and other suppliers) I ordered 2 (just in case) for a new install, along with a pump ring tool for hopefully precise tightening.

The diagram above and guidance on using a silicone sealant is very helpful, thank you.

Two questions: 1) can I simply install the gasket on the canister, seat the canister in the tank and screw down the ring? 2) what brand / type of sealant? Silicone comes in all shapes and sizes.

Thanks guys,
Aaron