'77 Pontiac w/301 won't stay running

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  #1  
Old 02-20-11, 01:51 PM
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'77 Pontiac w/301 won't stay running

Hi. We have a 1977 Pontiac LeMans with 301 ci engine. Before the heavy snowfall 2/01/11, the car had been running just fine. After the snow, we tried to start it and it would not start - just sat there cranking. We sprayed some starting fluid in the carburetor hoping that would make a difference but it did not. We'd had trouble with moisture years ago so replaced the rotor. Now it starts but will not stay running. Thought maybe one of the spark plug wires was bad and switched it out with another one. No improvement. Seems to be getting fuel - but maybe too much. Runs somewhat rough as long as keep pressure on accelerator pedal. Once put in gear, or take foot off accel pedal, the car dies. Fuel smell is strong under the hood. We replaced the fuel filter and this did not make any difference.

Could the ether/starting fluid have deteriorated something inside the carb? Since the car sat several days after the starting fluid was sprayed into the carb (too much snow and too cold to change the rotor outside of any bldg) before we were able finally change the rotor, could the starting fluid have caused damage (just "sitting" in the carb)?

Husband does not think anything is out of place with the distrib cap because car now starts.

Any ideas?

Thanks.
 
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  #2  
Old 02-20-11, 03:24 PM
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Location: Owen Sound Ontario Canada
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Problem with spark ignition engine is the high voltage, 12 to 30 thousand volts. Wow. Hard to contain at best of times. It degrades componts around it at a molecular level also.
So
That being said.
I would check the underside of the distributer cap very carefully for carbon tracking and check the distributer carbon button. I would just throw the ol............. Wait. I was going to say to throw the old coil wire away and replace with a new on but come to think of it the old 77s had the coil part of the distributer.
Another thing that gave them old GMs problems was the small control module inside the distributer. I thinik it boiled down to poor connections between the base of the distrubuter and the metal side of the control module but most people just ended up replacing them.
The easy way to diagnois them was to get a known good distributer unit and put it in. But nowdays a used unit would be hard to come by and I dont know how comfortable you two would be to swap the distributer.
I dont think it would have anything to do with the start fluid.

I would rule out igniton first. 8 brand new sparkplugs would do wonders also.
Make sure to look at the bottom of the cap for carbon tracks and the button.
Very common problems that are easy to miss
 
  #3  
Old 02-20-11, 03:44 PM
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301 eh????....A REAL Pontiac engine!!!!........Checking basics is #1 .condition of dist cap wires plugs................also COIL output can be a question. HOWEVER..........Be advised Pontiac V8's were well known for jumping timing chains
 
  #4  
Old 02-21-11, 01:35 PM
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Highly doubt jumped timing chain. I would add 5-10deg of adv on the timing and your issues should be gone. I say this assuming your plug wires and plugs are good. If your cars dies when it goes in gear that really points to a timing issue. Especially if the engine is cold. Starting fluid didn't damage anything.
 
  #5  
Old 02-21-11, 04:17 PM
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Like others I would recommend checking or replacing the distributor cap and wires. All that snow may have caused moisture to sink in to the wires if their old. One way of confirming that, although a little dangerous, is to spray the wires with WD-40 and let them sit for an hour or so. WD-40 will draw out the moisture, thus if it starts and runs better after trying that, it's time to replace the plug wires. Another thing I haven't seen asked or discussed would be your choke adjustment on the carburetor. Make sure it's not choking itself out, or choking too little. With the statement of strong fuel smell, I'd check for too much choke.
 
  #6  
Old 02-24-11, 08:12 AM
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wont start

I agree with most of what has been said. I doubt that the ign. module is bad as it does try to run. A visual insp of the cap is not always enough as they can burn thru under the coil. An automatic choke is ok as long as every thing else is good such as compression,ign,ect. If any of these things are off the choke keeps choking because it is cold and can "drown" the plugs,making it neccessary to replace them.If the wires havent been changed in the last couple of years they are a good bet. Like I always told my customers"if you want it to run perfect everything has to be perfect".
 
  #7  
Old 03-05-11, 05:59 PM
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How cold has it been. Could be ice in gas in any # of spots. Starting fluid should have fired it with good ignition, unless it was really flooded (Ice holding float down). Can you look down in the carb and see gas coming out of the sqirters. GM HEI distributors are famous for the Ignition module going bad due to the heat sink grease under them drying up and then over heating. That said, when they go it is a no start situation usually. I would check for gas at the squirters , change the plugs and try again. If you can get it someplace warm I would do that too.
 
  #8  
Old 03-06-11, 01:11 PM
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Originally Posted by weluvcars View Post
just sat there cranking. We sprayed some starting fluid in the carburetor hoping that would make a difference but it did not. We'd had trouble with moisture years ago so replaced the rotor. Now it starts but will not stay running. Thought maybe one of the spark plug wires was bad and switched it out with another one. No improvement. Seems to be getting fuel - but maybe too much. Runs somewhat rough as long as keep pressure on accelerator pedal. Once put in gear, or take foot off accel pedal, the car dies. Fuel smell is strong under the hood. We replaced the fuel filter and this did not make any difference.

Any ideas?

Thanks.

sounds like gas flooded engine/plugs. bless the wife, she must love the husband a lot, to ask HIS questions FOR HIM in a forum.

so, back to issue, though it's old and prolly fixed anyway by now. it's 77, so it's tired a little bit. ignition went south for a few hrs, plugs and engine got flooded with gas, now of course it will not run. take at least half plugs out, burn them white clean with propane torch. see what happens. also, carb might have gone south and keeps flooding engine with gas. strong fuel smell under the hood =gas is not burnt in cc-s completely.

also, don't forget to check on air filter.
 
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