Losing power when warmed up

R

rugreen

Junior Member
I have a 1929 CCPU Model A and it runs fine when cold, and even when its warmed up before stopping. However, when it is warmed up and I come to a stop or turn off the engine and start it back up, it loses all power (almost feels like it is running out of gas ... no backfiring though). I talked with another member in the local Model A club, and they said they had similar issues and it was the coil (when stopped the heat of the engine compartment would heat up the coil and cause issues). So, I swapped out the coil with the one from my 1930 coupe but it didn't resolve the issue. Has anyone else experienced similar problems with their A's losing power when warmed up after coming to a stop? Any insights would be greatly appreciate.
 
Stalling at a stop could be the carburetor flooding due to the fuel level to high in the bowl. If the carburetor is flooding, shut of the fuel just before you come to a stop. If you shut off a idling engine and it refuses to start do the same. Try starting with the fuel shut off after it gets started turn the fuel on. If it still stalls out go as stated above
 
rugreen,
If I understand you correctly, you're saying that after the car reaches normal operating temperature after driving for a while and then dies when you come to a stop, the car will restart but will not continue to run acceptably? What exactly do you mean by losing power?
 
Fhane said:
Stalling at a stop could be the carburetor flooding due to the fuel level to high in the bowl. If the carburetor is flooding, shut of the fuel just before you come to a stop. If you shut off a idling engine and it refuses to start do the same. Try starting with the fuel shut off after it gets started turn the fuel on. If it still stalls out go as stated above
Click to expand...
Thanks for the reply. No, the car isn't stalling when I come to a stop after a long tough drive, up a hill for example; it actually idles fine. However, when I come to a stop or hit slow traffice or shut the engine down to fill up with gas, for example, and start it back up, the car "stutters" when I try to accelerate and has no power. If I pull over to the side of the road and push down on the accelerator, the engine revs without any problems - but there is a complete lack of power to move the car. After the car has cooled down, it runs fine. I have a temperature gage installed and it doesn't seem to be an issue of the car overheating (temp ~170 deg F where the coolant exits the engine to flow into the radiator). But, I do think the engine compartment getting hot from driving up a hill at 45 mph and then rapidly bringing the car to an idle might be the cause of the issue.
 
mcgarrett said:
rugreen,
If I understand you correctly, you're saying that after the car reaches normal operating temperature after driving for a while and then dies when you come to a stop, the car will restart but will not continue to run acceptably? What exactly do you mean by losing power?
Click to expand...
I live in SW Virginia and drive on a lot of the back mountainous roads. After driving for 45 minutes on these roads the car is at operating temparature (~170 deg F where the coolant exits the engine and flows into the radiator) and is running fine. However, when I get into town and come to a red light, stop sign, or hit slow traffice, the car "stutters" when I try to accelerate - unfortunately, I can't think of a better word to describe it than "stutters." The car won't accelerate, but it doesn't stall - it actually idles fine and if I pull off to the side of the road and push the accelerator with the car it neutral, the engine revs fine. However, if I try to drive down the road, the car struggles going 10 mph. The engine doesn't backfire when it is having these issues. The closest thing that I can describe to the way the car acts is if you completely shut GAV after a long drive and try to drive up a steep hill - complete loss of power.
 
Fisher auto parts or Napa either one usually has condensors on the shelf. As was said above, no wait or shipping costs. I would get an extra and keep in each car.
 
Bob C said:
What gear are you in when you are going 10mph ?
Click to expand...
I have a Tremec T170 transmission in the '29 truck (4 speed with a sycronized clutch). 2nd gear on this transmission will get you going faster than 2nd gear on the originial transmission (I have an original transmission in my '30 coupe). So, when the truck is having this issue, it would struggle to go 10 mph in either 2nd or 3rd gear - it might actually stall if I put it in 3rd gear.
 
What carburetor are you using? Has it always had this issue? Did it ever run right before without having this problem?
 
mcgarrett said:
What carburetor are you using? Has it always had this issue? Did it ever run right before without having this problem?
Click to expand...
It has a Zenith carburetor (I assume the original one, although it might have been rebuilt sometime in its past). I've only owned the truck for a few months, and when I first got it I noticed that it struggled getting up some of the hilly roads around where I live. So, I had a Model A mechanic from the local club put a high compression head on it (as well as some other things). I've driven it a lot more since I got it back with the new head. So, the only thing I can compare it to is my '30 coupe, which has a Tillotson carburetor on it - no issues at all getting up the hills or losing power after a long tough drive. I originally thought it might be a carburetor issue until another member in the local Model A club mentioned he had similar issues and it was the coil.
 
Does it start easily when you first crank it up to go for a drive?
Does it run good, pull hills, etc. until you have to stop or slow down for traffic?

As eagle said...check the point gap for sure and while you're at it, check the timing and maybe have your mechanic friend check the timing gear to see if it might have jumped time. It's possible that the coil might be faulty, so replace it with a known good one. Condensers are a common failure item - cheap and easy to replace. Buy a good one like one of the "no burnout types" from Bratton's, Snyder's, etc.
 
Hey,

What about fuel evaporating in the fuel line?? Is that a thing with the Model A's??

I seem to recall some talk about that a while ago.. It would make sense to me if you are pushing it hard on the mountain roads and the fuel sitting in the fuel line close to the exhaust.. If you stop or just idle, the fuel will sit in that hot spot a lot longer than open throttle..

Just a thought..
 
Yes, we call it "vapor lock" and it can be a problem if the fuel line is situated too close to the exhaust manifold. It happens a lot down here in Texas, especially in our HOT summers It could certainly be contributing to his problem.
 
Since you have the 30 Coupe that is running well and if a new condenser doesn't help try using the carburetor and distributor on the pickup. One at a time.

Another thing comes to mind is it possible you have an issue in the muffler that is causing back pressure when it heats up?
 
You must log in or register to reply here.
Back
Top