Engine died, out of fuel??

[matt gineo]

I was driving my 76 2.7 around town last weekend, everything was running fine. I came to a stop sign and all of a sudden the thing dies instantly, no sputtering, coughing, surging etc., just instant death. Fuel gauge was a little below 1/8 tank (it's been below that level in the past) I checked fuel pump fuse, it was OK. Pulled the air box cover off and lifted the FD arm with ignition on, no fuel spray. I then checked the fuel level in the tank, (I have an access plate on top of the tank) the red fuel light was only on for a few miles. I Stuck my finger in the tank and there was almost 2 inches of fuel in the the tank.

I brought the car to my mechanic and he told me it was out of fuel. I was on level ground and at a complete stop when it died. My question is this, would the engine die instantly when getting low on fuel, and is 2 inches of fuel in the tank considered empty? I'm embarrassed to say that I've run out of fuel with other vehicles that I've owned and they would sputter and cough for quite a while before finally dying.

[KNS]

It's not the greatest idea to run the tank so low on fuel, especially with cars that have in-tank pumps.

I'm not sure what it is for the 911 but most cars have a small amount of unusable fuel.

[matt gineo]

Thanks Kurt, I'll definitely make sure that it doesn't get that low in the future. My 911 does not have an in tank fuel pump. again would the engine die instantly when out of fuel and is 2 inches of fuel in the tank considered empty?

[KNS]

No, the 911 pump isn't in the tank, bad idea none-the-less. It's certainly possible that it could simply die, how's it running now?

[matt gineo]

Still Skiing in Utah so I haven't had a chance to drive it yet. Mechanic said it runs fine after dumping 5 gallons of gas in tank.

[Paulporsche]

My car ran dry once in all the years I've had it about 15 years ago. The gauge read about 1/4 full. The same thing happened to my engine as yours--it just stopped. It appears that the gauge had just gotten temporarily stuck and failed to register correctly.

I put gas in it and it started right up. There was never any problem after that and apparently no damage was done to the fuel pump.

[ossiblue]

Take a look at the pictures in this thread: Fuel Tank Restoration !! Many Pictures

Your 77 has a swirl pot just like the one shown. The pot surrounds the outlet to the fuel pump and has a hole in the top for the fuel to enter. If you look closely, there are very small openings near the bottom to the swirl pot where fuel may enter as well. However, in an old tank with unknown amounts of debris/varnish/gunk, it's possible the small openings around the pot were clogged enough that once the fuel level dropped to a certain point--say two inches from the bottom--not enough could seep in to supply the demand of the CIS system. Just a theory but it may explain your situation. Remember, your system pumps a large volume of fuel in a loop, and if the pumps is being starved, inadequate fuel volume will kill the engine. CIS (Continuous Injection System) sprays fuel to all cylinders at the same time, unlike electronic injection, so when there is a loss of fuel at the injectors, it affects all of them at once instead of one at a time. No sputter, no cough, just no firing on six cylinders at the same moment.

[matt gineo]

Originally Posted by Paulporsche

My car ran dry once in all the years I've had it about 15 years ago. The gauge read about 1/4 full. The same thing happened to my engine as yours--it just stopped. It appears that the gauge had just gotten temporarily stuck and failed to register correctly.

I put gas in it and it started right up. There was never any problem after that and apparently no damage was done to the fuel pump.

Thanks Paul, I'll definitely be more aware of the fuel level in the future!

[Winter]

I had a rental ecobox in Italy a few years ago. Car was at 1/4 tank and then literally on empty. Died without nary a sputter! 5 kilometers to the next petrol station was 4 k too far!

Not all gas gauges are perfectly calibrated. And life is not perfect either. But I hear the skiing in Utah is pretty good right now so it sounds like you are ahead of the game!

[matt gineo]

yup, Alta has been sunny, 30-36 degrees , no crowds and petfect snow all week. Still no bare spots anywhere on the mountain!

[Winter]

Nice! That place is amazing and the Sitzmark bar in the Alta Lodge is one of the all-time greatest ski bars in the world!

[matt gineo]

thanks, never been there but I'll make sure to check it out and have a beer or two or thtee before I leave.

[manbridge 74]

My first 74 would not run with that low of fuel. But we have more hills around here and I attributed it to that.

[spuggy]

Originally Posted by ossiblue

Take a look at the pictures in this thread: Fuel Tank Restoration !! Many Pictures

Your 77 has a swirl pot just like the one shown. The pot surrounds the outlet to the fuel pump and has a hole in the top for the fuel to enter. If you look closely, there are very small openings near the bottom to the swirl pot where fuel may enter as well. However, in an old tank with unknown amounts of debris/varnish/gunk, it's possible the small openings around the pot were clogged enough that once the fuel level dropped to a certain point--say two inches from the bottom--not enough could seep in to supply the demand of the CIS system. Just a theory but it may explain your situation. Remember, your system pumps a large volume of fuel in a loop, and if the pumps is being starved, inadequate fuel volume will kill the engine. CIS (Continuous Injection System) sprays fuel to all cylinders at the same time, unlike electronic injection, so when there is a loss of fuel at the injectors, it affects all of them at once instead of one at a time. No sputter, no cough, just no firing on six cylinders at the same moment.

Great explanation & link; I was always advised never to run the fuel below the last few gallons in the tank in an old car; if you run them out, all the debris in the tank ends up around the pickup. Same as all the mud in a sink will end up around the plug hole.

Another reason not to run the fuel very low is that the unused fuel is pumped around continuously/back to the tank - because it is also used to cool the pump.

I plan a fuel stop as soon as the reserve indicator lights up nose-down on slopes; only ever managed to squeeze 18 US gallons into it once (usually less, like 17.5).

[porwolf]

Matt, I would not trust the fuel level gauge becaus it depends on the level sensor in the tank. That one could be compromised. I resored my level sensor from being completely frozen in place to completely functioning again. I would take it out, remove the outer tube and inspect it. Also I would check the resistance reading at various heights to make sure it functions properly. There are threads about that job here. Or you put a new one in, sold by the host. It is not that expensive, about $130.-.Ask if you need help.

[matt gineo]

Originally Posted by porwolf

Matt, I would not trust the fuel level gauge becaus it depends on the level sensor in the tank. That one could be compromised. I resored my level sensor from being completely frozen in place to completely functioning again. I would take it out, remove the outer tube and inspect it. Also I would check the resistance reading at various heights to make sure it functions properly. There are threads about that job here. Or you put a new one in, sold by the host. It is not that expensive, about $130.-.Ask if you need help.

Thanks for the info Porwolf, I have an easier and less expensive solution. I'll just consider 1/4 tank as empty.
Matt

[porwolf]

Matt, If you or anybody else wants to dig a little deeper and attempt to repair the fuel level sensing unit, here is a link that might be helpful:

New to Pelican and new 911 owner

[matt gineo]

Originally Posted by porwolf

Matt, If you or anybody else wants to dig a little deeper and attempt to repair the fuel level sensing unit, here is a link that might be helpful:

New to Pelican and new 911 owner

Excellent thread, thank you. I was only kidding about the inaccurate fuel sender. One of these days I will repair it, but even when it is repaired I won't let it get below 1/4 tank.

Mattt

[reachme]

reading threads like this, I made sure I never ran too low on fuel. Last night I needed to replace the original fuel hose that goes from the tank to the first fuel pump I ran the fuel lower than ever before. I made sure the light was on solid indicating low fuel and then I ran it a few more miles.
When draining I was glad I got a 5 gallon gas container because I needed every bit of it to drain out the remaining fuel.

Bentley says it is a 22.5 US gal tank so the light must kick on at just under 1/4 tank, I can't see the fuel return holding that much extra nor am I sure that would drain anyway without the pumps running.

Anybody else surprised at the amount of fuel remaining when the gauge (properly running) says empty?

[reachme]

Update.
Yes there was 5 gallons fuel to put back in
Yes that seems like about 1/4 tank and I could drive another 40 miles or so
But
Reality is I stalled after 4 miles on flat ground, out of fuel - I took the long way to refill the tank. Lesson learned, DO fear the red fuel light.