trouble with 1968 mustang

Hello,

I just recently bought a 1968 mustang coupe with a straight six. When I
bought it, it had been sitting for about a year. After driving it for
about ten minutes it began to sputter like it wasn't getting enough
gas. It ran for about thirty minutes and then it died on me and I had
to tow it home. I checked all the fuel lines to make sure their weren't
any leaks, and I checked the fuel filter and it was relativly clean.
Now when I drive it, it runs fine up to about 40-45MPH, but then starts
to sputter once I hit 45-50MPH. Does anybody out there have any
suggestions. I am considering replacing the gas tank and the fuel
lines, but as they are all originals (as is almost everything on the
car) I'd rather not do this. I am also considering adding an inline
fuel filter. Is this a good idea? Thanks

Seybertron wrote:

> Does anybody out there have any
> suggestions. I am considering replacing the gas tank and the fuel
> lines, but as they are all originals (as is almost everything on the
> car) I'd rather not do this. I am also considering adding an inline
> fuel filter. Is this a good idea?

Yes, it's better to have a filter.
For you problem check fuel pump performance pressure and flow capacity.

Regards,

Ralf
--
www.omnibusclub.de
Erfinder des Abgasturboladers Dr. Alfred J. Büchi: "Die Abgase,
deren noch inne-wohnende Energie bis dahin vergeudet wurde ..."

Seybertron wrote:

> Now when I drive it, it runs fine up to about 40-45MPH, but then starts
> to sputter once I hit 45-50MPH. Does anybody out there have any
> suggestions.

Before you do anything else, check for water in the gas tank. There may be a
layer of water in the bottom which gets shaken up at higher speeds. If so, it
should eventually get pulled through the system.

This is also typical of trash in the float bowl of the carb. A carburettor
typically runs a little lean at high speed and rich in the middle rpm range. If
something partially blocks the main jet, it will stumble at high rpm levels.
This should happen in any gear at high engine speeds.

If that's what it is, you'll have to open up the float chamber, remove the jet,
and clean things out. As long as you're doing that, you might want to just
rebuild and clean the carb.

Definitely get a fuel filter on the line to prevent a recurrence.

As for replacing fuel lines and such, check the system first. In addition to the
main jet, there are several possible bottlenecks. There's a strainer on the fuel
pickup inside the tank, the fuel pump may be going bad, and there may be a
strainer where the fuel line enters the carb. Check for that last one while
you're checking out the jet.

To check the pump, pull the line from the fuel pump to the carb and run it into
a quart jar. Remove the coil cable and have someone turn the starter. The pump
should produce strong jets of fuel and pump a pint in under a minute. Another
thing to check is the oil. Run the car for fifteen minutes or so, shut it down,
and check the dipstick. If the oil smells like gas, the pump diaphram has failed
in such a way as to pump gas into the crankcase. When that happens, fuel
consumption typically doubles.

You can check to see if the pump is getting a good intake flow by disconnecting
the fuel line under the car at the front. Gas should freely flow out of the
line. You can also get some idea of how much trash is in the gas tank by
draining it. Do this shortly after driving the car to shake any particles up.
Have some way of blocking the line handy, just in case the old fuel line breaks
up on you (or just plan on replacing that section of hose).

Do any of this outside with an extinguisher handy and keep smokers away.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

If you rebuild the carb, be sure to use a solvent that won't strip the
sealant from the inside of the carb.

Also, did a Mustang ever come with a straight 6 and three speed stick
with OD?
That would be nice but I doubt that there is room for the OD box and
still leave enough room for a decent length driveshaft.

MidLant

George Patterson wrote:
> Seybertron wrote:
>
> > Now when I drive it, it runs fine up to about 40-45MPH, but then starts
> > to sputter once I hit 45-50MPH. Does anybody out there have any
> > suggestions.
>
> Before you do anything else, check for water in the gas tank. There may be a
> layer of water in the bottom which gets shaken up at higher speeds. If so, it
> should eventually get pulled through the system.
>
> This is also typical of trash in the float bowl of the carb. A carburettor
> typically runs a little lean at high speed and rich in the middle rpm range. If
> something partially blocks the main jet, it will stumble at high rpm levels.
> This should happen in any gear at high engine speeds.
>
> If that's what it is, you'll have to open up the float chamber, remove the jet,
> and clean things out. As long as you're doing that, you might want to just
> rebuild and clean the carb.
>
> Definitely get a fuel filter on the line to prevent a recurrence.
>
> As for replacing fuel lines and such, check the system first. In addition to the
> main jet, there are several possible bottlenecks. There's a strainer on the fuel
> pickup inside the tank, the fuel pump may be going bad, and there may be a
> strainer where the fuel line enters the carb. Check for that last one while
> you're checking out the jet.
>
> To check the pump, pull the line from the fuel pump to the carb and run it into
> a quart jar. Remove the coil cable and have someone turn the starter. The pump
> should produce strong jets of fuel and pump a pint in under a minute. Another
> thing to check is the oil. Run the car for fifteen minutes or so, shut it down,
> and check the dipstick. If the oil smells like gas, the pump diaphram has failed
> in such a way as to pump gas into the crankcase. When that happens, fuel
> consumption typically doubles.
>
> You can check to see if the pump is getting a good intake flow by disconnecting
> the fuel line under the car at the front. Gas should freely flow out of the
> line. You can also get some idea of how much trash is in the gas tank by
> draining it. Do this shortly after driving the car to shake any particles up.
> Have some way of blocking the line handy, just in case the old fuel line breaks
> up on you (or just plan on replacing that section of hose).
>
> Do any of this outside with an extinguisher handy and keep smokers away.
>
> George Patterson
> Coffee is only a way of stealing time that should by rights belong to
> your slightly older self.

in line fuel filter, and rebuild the carb for a starter. if it still does it
after that, you will have to have the gas tank cleaned. also, has it had a
tune up recently?? it may be a bad condenser or a bad coil.
"Seybertron" > wrote in message
oups.com...
> Hello,
>
> I just recently bought a 1968 mustang coupe with a straight six. When I
> bought it, it had been sitting for about a year. After driving it for
> about ten minutes it began to sputter like it wasn't getting enough
> gas. It ran for about thirty minutes and then it died on me and I had
> to tow it home. I checked all the fuel lines to make sure their weren't
> any leaks, and I checked the fuel filter and it was relativly clean.
> Now when I drive it, it runs fine up to about 40-45MPH, but then starts
> to sputter once I hit 45-50MPH. Does anybody out there have any
> suggestions. I am considering replacing the gas tank and the fuel
> lines, but as they are all originals (as is almost everything on the
> car) I'd rather not do this. I am also considering adding an inline
> fuel filter. Is this a good idea? Thanks
>

My car did this when I got it. It turned out to be a bad ballast resistor
for the coil. It should have been about 1.5 ohms but was closer to 12 ohms.
The plug wires were bad too. Check your plugs.

You didn't say if you are still using the gas that was in it when it was
sitting. If so, get rid of it before doing anything else.

"Tom" > wrote in message
...
> in line fuel filter, and rebuild the carb for a starter. if it still does
it
> after that, you will have to have the gas tank cleaned. also, has it had a
> tune up recently?? it may be a bad condenser or a bad coil.
> "Seybertron" > wrote in message
> oups.com...
> > Hello,
> >
> > I just recently bought a 1968 mustang coupe with a straight six. When I
> > bought it, it had been sitting for about a year. After driving it for
> > about ten minutes it began to sputter like it wasn't getting enough
> > gas. It ran for about thirty minutes and then it died on me and I had
> > to tow it home. I checked all the fuel lines to make sure their weren't
> > any leaks, and I checked the fuel filter and it was relativly clean.
> > Now when I drive it, it runs fine up to about 40-45MPH, but then starts
> > to sputter once I hit 45-50MPH. Does anybody out there have any
> > suggestions. I am considering replacing the gas tank and the fuel
> > lines, but as they are all originals (as is almost everything on the
> > car) I'd rather not do this. I am also considering adding an inline
> > fuel filter. Is this a good idea? Thanks
> >
>
>
>

Look for 1) trash in the carb fuel bowl gets sucked into the jets as you
cruise 2) trash in the tank gets sucked over the pick up of the filter sock
has been removed 3) the volume of the fuel pump!
You should always run a fuel filter!!
"Seybertron" > wrote in message
oups.com...
> Hello,
>
> I just recently bought a 1968 mustang coupe with a straight six. When I
> bought it, it had been sitting for about a year. After driving it for
> about ten minutes it began to sputter like it wasn't getting enough
> gas. It ran for about thirty minutes and then it died on me and I had
> to tow it home. I checked all the fuel lines to make sure their weren't
> any leaks, and I checked the fuel filter and it was relativly clean.
> Now when I drive it, it runs fine up to about 40-45MPH, but then starts
> to sputter once I hit 45-50MPH. Does anybody out there have any
> suggestions. I am considering replacing the gas tank and the fuel
> lines, but as they are all originals (as is almost everything on the
> car) I'd rather not do this. I am also considering adding an inline
> fuel filter. Is this a good idea? Thanks
>

I believe the only 1960s compact cars with overdrive are the Rambler
American and the Studebaker Lark. The big 3 cared less about gas mileage.

Ken D.

> wrote
> Also, did a Mustang ever come with a straight 6 and three speed stick
> with OD?
> That would be nice but I doubt that there is room for the OD box and
> still leave enough room for a decent length driveshaft.
>
> MidLant
>