Losing fuel?

[boogiedude]

So I seem to be losing fuel somewhere, or my engine is guzzling for some reason. For the past several months my average mpg has been low 20's, but these past two weeks I've seen a drastic drop in fuel economy(down to about 10-12mpg, I went through 3 gallons of gas in less than 30 miles) for some reason. I haven't done any tuning/changing of settings from when it ran well until the drop, so I'm hard pressed to believe that it's actually being burnt and used up I've gone through and checked all the transitions from hard to soft line and such from the tank to the engine, and I've checked all the fittings to/from the carb and fuel filter. Nothing is wet, nothing seems to be leaking. I also haven't noticed the smell of gas in or around the car lately.

Basically I'm completely stumped. I know my connections are good, and I know gas is disappearing somewhere, but I can't find WHERE it's going.

Any pointers as to where to look next?

[manoa matt]

Funny because my car suddenly has more gas and I have a strange taste in my mouth from sucking on a hose. Just kidding.

Did you tighten the fuel filler hose when you put the tank back in? Fill up the tank and park it, see if any gas is comming out near the tank. My first spider had a leak at the tank seam and I could only fill it up half way or it would leak out on the ground.

How about that missing hose clamp on the supply line at the carb inlet?

When you checked the supply and return lines was the pump running? Since you installed that electric pump it pushes instead of pulls, so it could push gas out at a transition from hard to soft line under the car.

[boogiedude]

Ya I had the pump on the whole time, and spent a good 15 minutes watching all the transitions. I didn't do the rear bumper delete so I never took off the filler neck. I also monitered the tank and the ground around the car the past couple days. No puddles or leaks thar I've found.

[katsi]

Funny because my car suddenly has more gas and I have a strange taste in my mouth from sucking on a hose. Just kidding.

LMAO - that was funny.

Back to the subject. You either have a spit hose that is leaking under running pressure or you have a hole in the tank somewhere. Maybe when you stop or get going the sloshing is hitting a hole somewhere.

Or, maybe you have an neighbor who has the strange taste of gasoline in his mouth.

Finally, it is not at all un-phathomable that the gas station you are using is shorting you fuel.

Good luck!

[engineerted]

So you installed an electric pump, did you remove the mechanical pump, or are you running it in series? If in series check your dip stick for oil level, you may have blown the diaphram in the mechinical pump.

Ted

[boogiedude]

The mechanical pump is still installed but is not hooked up to fuel. It functions purely as a musical instrument right now.

[jfrawley]

Had the same issue when I first got mine running and couldn't find the issue. Only when I had it up on jack stands and running did the hose near the fuel pump leak. It was fine when just sitting. Changed the hose and my mileage jumped right back up. Just a thought.

John

[agarair]

Many years ago I had a similar problem, although not as severe, in my 71 124 Spider. A metal line had vibrated against the body in one spot near the firewall to the point it wore a small pin hole, and was leaking fuel. Being very warm in the engine bay, the small leak evaporated away while I was driving or the car was hot, and I didn't smell it for a about a month. Then late one cold New Hampshire night when I walked by the car I smelled the fuel leaking, found it with a flashlight. Repaired it, and my mileage came back up about five miles per gallon, and I have now lived another35 years without exploding! Still have the car, just rebuilt the carb and got her back on the road today! Good luck at finding your leak, sure sounds like the problem.