Mysterious intermittent fuel leak
#17
Rennlist Member
#18
Burning Brakes
Thread Starter
Yes, I've seen write-ups of how to make home-made charcoal canisters online. Since my car lives in a garage, I will probably want to do that before next summer.
#19
Burning Brakes
Thread Starter
Well, I released the fuel pump from the hose clamp that attaches the pump to its housing so I could get a good look at all the lines, jumpered the DME relay, and again, nothing, which is very weird considering how fuel was literally gushing out on Friday night. I let the pump run for a minute or so, but didn't want to run down the tiny lithium ion phosphate battery (it is a track car, remember), so I started it up, and let it run for a few minutes. Finally, I saw the makings of a droplet of fuel around the fittings on the outlet side of the pump, as can be seen in this image:
http://cdn4.pelicanparts.com/techart...mall/pic08.jpg
Over time, the droplet got bigger, and there is no sign of any other leaks upstream in any of the other lines. The leak is happening directly under the fuel pump, so it does appear that I've identified its source. But what has me puzzled is why the severity of the leak varies so much. I only started it up long enough on Friday night to pull it out of my driveway to allow me to turn the car around in the garage because I had some other work to do on the car on the drivers side, which normally is against the garage wall. In that time, A LOT of fuel spilled out, enough to stink up the garage to the point where my wife didn't want to bring her car in. Yet today, takes at least ten minutes of running to form a drop large enough to drip onto the ground.
One possible contributing factor is that today, I have the rear of the car up on jack stands, whereas on Friday night, all four wheels were on the ground. Also, the leak seems to be worse when the fuel pump is secured in place by the hose clamp that goes around. I tried holding the pump in it normal mounting spot to mimic its normal orientation, but that didn't make it leak any faster. It is significantly cooler today, although it was only in the high seventies or low eighties on Friday night, which is unusually warm for this time of year, but not hot my any means. Any ideas as to what could be causing this weird intermitttency?I checked the tightness of the securing nuts, and they appear to be perfectly secure.
As far as the leak itself, does anybody know if it's common for fuel pumps to start leaking in this spot? I'm sure it's the original pump (so it's 25 years old), but is it likely to be just the seals (referred to as "sealing rings" in the parts catalog), or should I go ahead and replace the entire pump? It isn't hard to take on and off, so I suppose I could try replacing the three seals fist, and if that doesn't fix it, replace the pump. Anybody ever run across a problem with symptoms like this? And I suppose the theory that there's a clop in the evap system causing excess pressure build-up could still be a contributing factor, as a pressurized system could cause a marginal sealing ring to vary in its ability to seal. Thanks.
http://cdn4.pelicanparts.com/techart...mall/pic08.jpg
Over time, the droplet got bigger, and there is no sign of any other leaks upstream in any of the other lines. The leak is happening directly under the fuel pump, so it does appear that I've identified its source. But what has me puzzled is why the severity of the leak varies so much. I only started it up long enough on Friday night to pull it out of my driveway to allow me to turn the car around in the garage because I had some other work to do on the car on the drivers side, which normally is against the garage wall. In that time, A LOT of fuel spilled out, enough to stink up the garage to the point where my wife didn't want to bring her car in. Yet today, takes at least ten minutes of running to form a drop large enough to drip onto the ground.
One possible contributing factor is that today, I have the rear of the car up on jack stands, whereas on Friday night, all four wheels were on the ground. Also, the leak seems to be worse when the fuel pump is secured in place by the hose clamp that goes around. I tried holding the pump in it normal mounting spot to mimic its normal orientation, but that didn't make it leak any faster. It is significantly cooler today, although it was only in the high seventies or low eighties on Friday night, which is unusually warm for this time of year, but not hot my any means. Any ideas as to what could be causing this weird intermitttency?I checked the tightness of the securing nuts, and they appear to be perfectly secure.
As far as the leak itself, does anybody know if it's common for fuel pumps to start leaking in this spot? I'm sure it's the original pump (so it's 25 years old), but is it likely to be just the seals (referred to as "sealing rings" in the parts catalog), or should I go ahead and replace the entire pump? It isn't hard to take on and off, so I suppose I could try replacing the three seals fist, and if that doesn't fix it, replace the pump. Anybody ever run across a problem with symptoms like this? And I suppose the theory that there's a clop in the evap system causing excess pressure build-up could still be a contributing factor, as a pressurized system could cause a marginal sealing ring to vary in its ability to seal. Thanks.
#20
Burning Brakes
When I replaced my fuel pump a long time back I remember mine initially leaking from that exact same spot; I was surprised how much I had to tighten it before it stopped the leak. Odds are its likely the copper crush washers if you have ever disassembled it prior.
#21
Quit Smokin'
Rennlist Member
Rennlist Member
The tank on my track car developed a leak right where the filler neck attaches to the tank. The flange is actually a separate piece from the rest of the tank, and it was leaking at the joint and dropping down / making a mess on the right side of the car. It would notice it after thrashing the car with a full or nearly full tank. It would also begin to drip if I jacked the driver's side up by itself when there was a big load of fuel.
#22
Burning Brakes
Thread Starter
Mine only leaks when it's running, and the leak is very intermittent - sometimes nothing, other times a serious gusher, and it's definitely coming from the fuel pump area. All the lines in the vicinity of the leak are bone dry. Jay at Paragon Products told me that from my description, it definitely sounds like the pump itself. He says it's common for them to leak from the seam that's held together by a series of crimps at the high pressure end of the pump. So, I ordered a new one. It comes with a new check valve, and all the seals, so hopefully this is it.
#23
Mine only leaks when it's running, and the leak is very intermittent - sometimes nothing, other times a serious gusher, and it's definitely coming from the fuel pump area. All the lines in the vicinity of the leak are bone dry. Jay at Paragon Products told me that from my description, it definitely sounds like the pump itself. He says it's common for them to leak from the seam that's held together by a series of crimps at the high pressure end of the pump. So, I ordered a new one. It comes with a new check valve, and all the seals, so hopefully this is it.
I am having a similar issue regarding and intermittent fuel leak. Once right after I filled up and did ~30 min on the track. Another time after car sat in garage for a few very hot days (~40 degrees celsius ). I can actually hear 'gurggling' from the fuel filler / tank area when it is about to leak. If I open gas cap there is quite a bit of pressure that is released. Starting to think evap system not doing well... not sure how to validate that though and was wondering how your issue went?
Thanks!
#24
Burning Brakes
Thread Starter
Well, I'm not sure this will help you, but mine turned out to simply be a leaking fuel pump, most likely along the seam, as Paragon predicted. No issues with the evap system in my case, as far as I can tell. Good luck.