stalling at temp

[Nige]

1973 / 351c / motorcraft 2100d / c6 transmission 

have used rebuild kit 

set choke pull down / set auto choke rich 1 / set fast idle cam / set idle in drive at 550 rpm and 1000 rpm in neutral

starts from cold great at around 1500 rpm

choke opens and idles at 1000 rpm

and drives great until

10 or 15 miles later rpm get higher in neutral and sometimes stalls when stopping at junction in drive but will rev high if put in neutral before stalling

before stalling sounds like revs getting slower and slower

hope this makes sense 

Thanks Nige

 

[Don C]

It sounds like a vacuum leak develops after it warms up. Do you have emissions in place and connected? I would start by checking all vacuum lines. It could also be fuel starvation. Make sure you have a good fuel supply, check fuel pressure and volume after it warms up. Make sure none of the fuel lines are touching or in close proximity to the exhaust system.

 

[c9zx]

Try adjusting the mixture screws when the car is at operating temperature. What it like when it is cold may be too rich for when it is at operating temperature. Did you set float level? Just ideas. Chuck

 

[Nige]

Thanks for the info guys will check when rain stops .

 

[Bill73Ragtop]

It sounds like a vacuum leak develops after it warms up. Do you have emissions in place and connected? I would start by checking all vacuum lines. It could also be fuel starvation. Make sure you have a good fuel supply, check fuel pressure and volume after it warms up. Make sure none of the fuel lines are touching or in close proximity to the exhaust system.

Vacuum leak.  If idle at full operating temp is set at 1000rpm (think that's what you meant) it is way too high for typical operation.  650 -700rpm is more like it.

Once had same condition and it turned out to be intake manifold gasket leak which took months to eliminate all other possibilities before changing the gasket and resolving the issue.  Hope yours turns out to be carb gasket or vacuum hose before it gets to that.

 

[Don C]

In addition to vacuum hoses, items like the EGR valve, vacuum advance, brake booster, and air cleaner snorkel that have vacuum diaphragms should be checked.

 

[Nige]

It sounds like a vacuum leak develops after it warms up. Do you have emissions in place and connected? I would start by checking all vacuum lines. It could also be fuel starvation. Make sure you have a good fuel supply, check fuel pressure and volume after it warms up. Make sure none of the fuel lines are touching or in close proximity to the exhaust system.

Hi no the emissions egr was already removed will be checking fuel lines next float level is correct.

 

[Nige]

It sounds like a vacuum leak develops after it warms up. Do you have emissions in place and connected? I would start by checking all vacuum lines. It could also be fuel starvation. Make sure you have a good fuel supply, check fuel pressure and volume after it warms up. Make sure none of the fuel lines are touching or in close proximity to the exhaust system.

Vacuum leak.  If idle at full operating temp is set at 1000rpm (think that's what you meant) it is way too high for typical operation.  650 -700rpm is more like it.

Once had same condition and it turned out to be intake manifold gasket leak which took months to eliminate all other possibilities before changing the gasket and resolving the issue.  Hope yours turns out to be carb gasket or vacuum hose before it gets to that.

Thanks i will look into the manifold gasket

 

[kcmash]

Are you running a Pertonix?  That is exactly what I could not figure out for a while.  Ran great for 5 minutes, starts cutting out, then would die.  Went to points and I am HAPPY!

kcmash

 

[Mister 4x4]

Are you running a Pertonix?  That is exactly what I could not figure out for a while.  Ran great for 5 minutes, starts cutting out, then would die.  Went to points and I am HAPPY!

kcmash

I think you might actually be the first person I've ever heard of where switching back to points was actually better!

 

[Carolina_Mountain_Mustangs]

My 73 Mach 1 has never had anything but points. Simple easy to get parts for so why change it, lol. My other 73 came with MSD but do not see it making a difference. I run non ethanol in both.

There are two pumps in the carb and some say to eliminate the smaller one that it feeds too much fuel into the carb.  I never had time to do any tuning or checking on the Mach 1 rebuilt the carb put it on started it and drove into trailer and then into the museum.

 

[Nige]

Just an update turned out to be the ignition coil expanding and braking circuit when hot and shrinking back and working fine when cold.

runs great now no stalling at all.

 

[c9zx]

Just an update turned out to be the ignition coil expanding and braking circuit when hot and shrinking back and working fine when cold.

runs great now no stalling at all.

Glad you found and fixed the problem, well done. Chuck