Elec fuel pump runs but no pressure when car is warm

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MIGHTY 8
Posts: 307
Joined: Sat Mar 04, 2006 9:55 pm
Your car is a: 1980 Spider
Location: North Chatham NY

Elec fuel pump runs but no pressure when car is warm

Post by MIGHTY 8 »

Hello all.

Drove car well enough for about 15 miles. Then got into traffic, water temp went just about 200 d. and car dies.

Looked in engine compartment, and aftermarket fuel gauge reads zero pressure but upon touching the elec pump underneath the car I can feel it running.

Waited till she cooled off, sucked on the fuel line before the carb and out comes the gas! Runs fine (with pressure on the gauge) then again hit traffic, temp goes up and back to step one.

Got 'er home, but not too happy about this one!
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azruss
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Re: Elec fuel pump runs but no pressure when car is warm

Post by azruss »

almost sounds like you are developing pressure in the gas tank that wont allow the fuel to return.
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divace73
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Your car is a: 1980 Fiat 124 Spider Silver
Location: Sydney, Australia

Re: Elec fuel pump runs but no pressure when car is warm

Post by divace73 »

could your fuel line be blocked?
Cheers David
-=1980 silver Fiat 124 Spider=-
If you want to see pics of my car (and other random stuff) >>click here<< OR
see my >>You tube channel<<
MIGHTY 8
Posts: 307
Joined: Sat Mar 04, 2006 9:55 pm
Your car is a: 1980 Spider
Location: North Chatham NY

Re: Elec fuel pump runs but no pressure when car is warm

Post by MIGHTY 8 »

azruss wrote:almost sounds like you are developing pressure in the gas tank that wont allow the fuel to return.

Thanks, but I've been running sans return line.
MIGHTY 8
Posts: 307
Joined: Sat Mar 04, 2006 9:55 pm
Your car is a: 1980 Spider
Location: North Chatham NY

Re: Elec fuel pump runs but no pressure when car is warm

Post by MIGHTY 8 »

divace73 wrote:could your fuel line be blocked?
It's quite possible. But it doesn't explain the inclusion of the temperature variable. As long as she's around 190F, she'll run all day long.

Thanks all for your input. Still scratching my head on this new development.
baltobernie
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Your car is a: 1973 Spider [sold]
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Re: Elec fuel pump runs but no pressure when car is warm

Post by baltobernie »

Try running with the gas cap loose next time.
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divace73
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Your car is a: 1980 Fiat 124 Spider Silver
Location: Sydney, Australia

Re: Elec fuel pump runs but no pressure when car is warm

Post by divace73 »

MIGHTY 8 wrote:
azruss wrote:almost sounds like you are developing pressure in the gas tank that wont allow the fuel to return.

Thanks, but I've been running sans return line.
Not sure which model fuel pump you have, but if it is the bosch type there needs to be the return line to keep the fuel flowing which in turn keeps the pump cool. You can imgiane the strain on a pump if it is allowed to build up pressure, I accidiently did this with my 1980 with an adjustable fuel pressure regulator and the pump stopped. The FI type of pump will also burn out if you run it without fuel.

I wonder if your pump is running at its limits without the retun line and once ambient temp rise it stops??

Is it possible to reconnect the return line as see if it still happens?
Cheers David
-=1980 silver Fiat 124 Spider=-
If you want to see pics of my car (and other random stuff) >>click here<< OR
see my >>You tube channel<<
baltobernie
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Your car is a: 1973 Spider [sold]
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Re: Elec fuel pump runs but no pressure when car is warm

Post by baltobernie »

The OP did not state the fuel system in his car. I assumed it was carburetor, and many carbs don't require a return line. But all fuel systems need a way to replace the volume of fuel consumed from the tank. I'm taking a SWAG here in thinking his problem is time-related, not temperature-related.
MIGHTY 8
Posts: 307
Joined: Sat Mar 04, 2006 9:55 pm
Your car is a: 1980 Spider
Location: North Chatham NY

Re: Elec fuel pump runs but no pressure when car is warm

Post by MIGHTY 8 »

It's carbed.

And thanks all for your assistance. I changed out the elec fuel pump and without a really long test drive to confirm yet, I'm pretty sure it's the source of my problem.

Forgot to mention that this occurred after I discovered my car had substantial water damage when left at a local garage during hurricane Sandy.

There was lots of corrosion on the electrical connectors upon replacing the pump :twisted:
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