Engine stalling on the way to the Vintage x 2

Terry S.

Terry S.

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My 1972 CS has been intermittently stalling after about 1 hour or so - this has happened on the way to the Vintage this year, and happened back in 2019 on the way as well. I changed the electric low flow fuel pump to my Zeniths in 2019, and it worked fine up to this year's trip. I've carried a spare fuel pump with me, and was ready to put it it, but after waiting 30 minutes, the engine restarted perfectly, and I was able to make it to Hot Springs no problem. Drive back home was uneventful, too.

Fuel filter is new and tank intake mesh filter is clean as well. I've read the thread about 'Julia' on the way to the vintage and read Rob Seigel's experience with his coupe stalling due to a loose barrel connector as well. The engine runs cool (new SS radiator 5 years ago) and when it stalls, I have no warning - it just dies. I am getting ready to drive up to Blowing Rock this weekend, and have a spare pump ready to go, but I wonder if a faulty/intermittent pump relay might be causing this. When I've removed the older pumps and check them, they seem to be working OK. Tank is full to 3/4 when this happens - I do notice a vacuum feeling on the gas cap when getting low, but the stalling doesn't seem to occur then.
 
Also check the return line from the engine to the tank. Mine stalled but would restart for a while and then stall again. I had sealed the tank with POR 15 but not cleared the return inlet on the tank.
 
Terry S. said:
I changed the electric low flow fuel pump to my Zeniths in 2019...

...When I've removed the older pumps and check them, they seem to be working OK.
Click to expand...
How many fuel pumps on the car?

Is "the electric low flow fuel pump" only to prime the carbs or does it run all the time the car is running?

What do you mean by "older pumps"?
Rek said:
Also check the return line from the engine to the tank.
Click to expand...

Would a carbed car have a return line? (Moderator: not until 74) Do you mean the tank vent line that goes through the charcoal filter under the battery then on to the air cleaner?
 
Last edited by a moderator:
Where is the electric pump? Mine was mounted by a PO above the muffler. Ran fine until in traffic w/ no air flow, then pump got hot and stopped.
 
OK - MADE IT to Blowing Rock tonight with no stalls - I will check the return line - thanks (Mike) for the diagram - there is 1 electric pump mounted in the engine bay, on the left near the master cylinder/brake booster. It has been an electric pump since I've owned it (2006) - the mechanical pump had already been removed by the previous owner. The older pumps I mentioned were the ones I've replaced. So, only one active pump.

Acceleration is great - cruising at 70 no problem and plenty of power making it through the foothills of North Carolina up through North Wilkesboro (and by the old NASCAR track - grandstands easily visible from the highway).

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Thanks for all of the responses - this is the first time I've asked a technical question on this forum and this is great!
 
Terry S. said:
there is 1 electric pump mounted in the engine bay, on the left near the master cylinder/brake booster.
Click to expand...
If it were me I would get the pump out of the engine bay and mount it lower and near the tank like a 2002Tii. Mine is attached to the diff, away from heat and possible vapor lock.
 
If you have a fuel pump problem, the car will run poorly before it stalls due to lack of fuel in the float bowls.

When you say "it just dies" could you elaborate a bit more? if it dies instantaneously like someone flipped a switch, it's more likely to be an ignition fault.
If it starts to stumble, miss, or not respond to the accelerator, then maybe it's a lack of fuel in the carb float bowls (bad pump, vacuum, clogged line, etc.

John
 
John, it is much more like the second - I can feel a delayed response to the throttle, and then I have about 5-10 seconds where I stay on the throttle to keep the engine going and have just enough time to pull over before it completely stalls.

No problem getting back down the hill from Blowing Rock - spent Saturday morning with an XKE and TR6 and the return drive on the Blue Ridge Parkway was smooth.

It seems to stall more when it is warmer - it was about 70 degrees this weekend whereas when it stalled on the way to the Vintage it was about 85.
 

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Sorry, just noticed that it is a carb car from Dicks comment. No return line on that. How about checking and cleaning the distributor. Mine arced across the terminals heating it up and stopped working until it cooled down again.
It seemed like it was fuel pressure but it wasn't.
 
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