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Posts: 14
| Forgive me everyone--I'm new here, and I'm at my wits' end with this engine, and I figured I'd beg the internet for advice. '58 Plymouth Belvedere, 318 ci poly, 2bbl Carter BBD 2409S carb. Powerflite. The car was recently moved from low altitude (~2400 ft) to high altitude (~6200 ft.) The car will usually run fine around town for a total of 15-20 minutes, and then will stall with absolutely no good reason. The engine stumbles for a couple of turns, and then stalls smoothly. It will usually fire up right away after stalling, but continues stalling until I can limp it into the driveway.
Here's what's been tried:
Carb adjusted for higher altitude--still may be running slightly rich. 15psi of vacuum. Lots of carbon depostits coming from the exhaust.
Accelerator pump adjusted for a longer stroke--seemed to work for a little while, but we're back to the same problems. Stroke is at 1 1/32" from top of carb bowl.
Floats adjusted--previous owner had floats way too high, and carb was leaking gas onto the intake. Top of float is now at about 1/4 inch (9/32) below top of carb wall.
Spark plugs replaced. Old plugs were carbon fouled from rich running.
Fuel filter replaced, because why not? Clear fuel filter shows steady supply of fuel from pump, at least at idle.
New vented fuel cap--better vent, and seems to be a better fit. Was hoping it was as simple as that.
Good dwell, good ignition timing, idles at 500 RPM, timing is all good.
What in the Sam Hill am I missing?
Thanks! |
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Expert 5K+
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Location: Lower Mainland BC | Stalling in neutral or with D or L pushed in? If in gear, you might need to adjust the Neutral idle speed up a tad.
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Member
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| As an example, I was crusing down the boulevard at around 35 mph in high gear, when I felt the engine start to sputter. I was able to get it into the center lane and stopped before it finally cut out. The stall is so smooth, sometimes it's hard to recognize what happened until you feel the power steering quit. |
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Veteran
Posts: 148
Location: Mandurah, Western Australia | I would suspect an electrical problem, either condenser or coil that fails when hot, but ok cold. Have seen similar behaviour several times over the years |
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Expert 5K+
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Location: Lower Mainland BC | bdpt109 - 2016-12-28 5:38 PM As an example, I was crusing down the boulevard at around 35 mph in high gear, when I felt the engine start to sputter. I was able to get it into the center lane and stopped before it finally cut out. The stall is so smooth, sometimes it's hard to recognize what happened until you feel the power steering quit.
Okay. I am sure you will get other suggestions but that sounds to me like fuel starvation, i.e. either a weak fuel pump or you are actually running low on fuel in the tank and/or there is an issue in the tank or between the tank and the fuel pump. I would start with adding at least 25 L (6 US gal) of fuel to the tank and see if that helps the situation.
I had my new to me 56 Custom Royal go very lean while driving = lean backfire on acceleration under load (up a hill) and then stall while idling in front of my house. Turns out that my fuel gauge wasn't hooked up and my assumption about the fuel level in the tank was wrong. (I had run out of fuel). I added 25L of 92 and it basically started right up an performed much better.
Otherwise, you might have to consider that the fuel pump needs retirement and replacement.
Good Luck.
Edited by 56D500boy 2016-12-28 6:06 PM
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Member
Posts: 14
| I hadn't considered the coil or condenser since the spark seemed to be strong, but it does make sense. I had no idea why the car would run fine, but start to have problems once the temperature increased. I'll check it out. I will also try filling the tank and seeing if fuel is still cycling through. Fuel starvation was my first thought, and I'll see if it changes under heavy load
Edited by bdpt109 2016-12-28 6:36 PM
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Expert
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Location: NorCal |
Sounds fuel related, could be something as simple as an un-vented fuel cap....leave it off foe awhile and see if it helps. |
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Expert
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Location: Connecticut | You said you have 15" Hg for a vacuum reading. That's low. Should be 18-20. You said that timing was good. What are your numbers ? Did you plug the vacuum line before testing ? Correct Carter BBD carb for 58 Ply with Powerflite is 2646S. I would reset all the 'high elevation' stuff to regular setting. The high elevation is offset fuel-wise by the lower octane rating of the gas (85 for regular, for example). Have you pressure tested your fuel pump ? Should be 7 pounds maximum. Some aftermarket fuel pumps are as high as 9 or more. Not good. I also agree with Chizler. Try driving with fuel cap loose, to see if that solves the problem.
Edited by ronbo97 2016-12-28 9:33 PM
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Expert
Posts: 1740
Location: Alaska | 15" of vacuum may be about normal for over 6000' of altitude. Remember, air is thinner so vacuum reading will be lower.
I would try other things already mentioned first but it could be carb is jetted too rich for altitude.
Edited by 58coupe 2016-12-29 9:56 AM
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Expert
Posts: 3033
Location: N.W. Fla. | If it's the coil and/or condenser, you might consider dropping in an LA 318 electronic dizzy & system. |
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Member
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| Thanks for the suggestions so far folks--tried driving around without the gas cap--unfortunately the easiest fix wasn't the right one. Now she doesn't seem to want to go at all--stalling on acceleration has become more of an issue. Fuel pump pressure is okay, so I am having a spare carb rebuilt, and we'll see if that one presents with better luck. I also took a look under the distbutor cap, and was greeted with a corrosion explosion of sorts. So I think a replacement with a LA 318 dizzy is in the near future. It couldn't be any sort of transmission issue could it? (I'm new to the powerflite) Seems to shift okay, but the stalling seems to be more of an issue when she reaches the point of upshift/downshift.
I'm always still open to more ideas. We'll get this licked yet! |
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Expert 5K+
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Location: WHEELING,WV.>>>HOME OF WWVA | has the fuel line ever been cleaned or the wire from the dist. to coil checked------------------------------------------------later |
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Expert
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Location: N.W. Fla. | bdpt109 - 2016-12-30 2:47 PM
. It couldn't be any sort of transmission issue could it? (I'm new to the powerflite) Seems to shift okay, but the stalling seems to be more of an issue when she reaches the point of upshift/downshift.
! Had that problem on an O/T car. Bad plug wires. At high RPM they were breaking down. |
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Veteran
Posts: 214
| Have you tried looking at the ignition resistor? I had a similar problem in my 60 Plymouth with the 318. The car would just die and start up and then finally didn't start. clean the terminals at the ignition resistor, both of them very good and your problem may be solved. |
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Expert
Posts: 1231
Location: York County, PA | Bad coil. Getting too weak to hold a spark |
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318 Stalling without a good reason
