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Very Odd Situation 3 of 4 Outings in a Row, Please Read

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Very Odd Situation 3 of 4 Outings in a Row, Please Read

 
Old 03-06-2019, 09:29 PM
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Jstan2014
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Default Very Odd Situation 3 of 4 Outings in a Row, Please Read

The strangest thing has happened 3 of the last 4 outings in our C3. (1972 Base Coupe, 350 w/auto 87K miles). I/we make it almost exactly 1.2 miles and the car begins to lurch forward and surge between 2K - 3K rpmís and then dies as though itís out of gas. This happens while accelerating or driving between 30-45 mph. 3 of these times, the car had not been driven between 3 and 10 days and the car had been kept at our storage unit. Today was the 3rd time this has happened and, like clockwork, I made it the same distance away from the unit when it died. Each time, the engine starts back up right away and I/we are able to continue driving with NO further problems. We drive out to the highway or toll road and drive 10-15 miles with no trouble. She runs great. The only time this didnít happen was two weeks ago when the car had been parked in our garage. The car was in the garage for 5 days. She started right away and ran perfectly fine for a 24 mile round trip.

Iím wondering if condensation is building in the fuel lines or tank while the car is in the storage unit, makes itís way to the carb, causes the car to run like crap and die, and then clears out and runs fine? It happens each time after the same distance. This really seems beyond coincidental. Each time the engine was ďwarmed upĒ about 5- 10 minutes before being driven on the road. Iíve added some fuel stabilizer today. I always keep fresh, tier 1, 93 octane fuel in the tank. (I add fresh fuel every time a drive the car and keep the tank about half full at all times). I donít fill the tank, because the vapor return line was cut by the previous owner and gas will spill out when turning/cornering if the tank is full). This situation started about 6 weeks ago, and as of today, has now happened 3 times. Iíll drive the car tomorrow and I guarantee it wonít happen. It never happens after the car has been garaged at home and if it was driven the previous day. This only happens after the car has not been driven for several days and it was kept in our storage unit. Hopefully Iíve explained this well enough for everyone to understand whatís going on. Please comment if you have any ideas as to whatís causing this, or ask any questions you may have. Could it be condensation in the tank or fuel lines? The fuel filter has less than 300 miles on it and the fuel tank was replaced by the previous owner in 2017. Iím stumped and canít figure out this mystery.

The ďhome-away-from-homeĒ storage unit.
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Old 03-06-2019, 09:33 PM
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Greg
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Are you in an ethanol state?
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Old 03-06-2019, 09:45 PM
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Sounds like an electrical problem to me....Not sure why it only happens after being in the storage unit.

Brian
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Old 03-06-2019, 09:53 PM
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Originally Posted by Greg View Post
Are you in an ethanol state?
Yes. Everything around here is at least 10% ethanol.
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Old 03-06-2019, 09:56 PM
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Originally Posted by Wee View Post
Sounds like an electrical problem to me....Not sure why it only happens after being in the storage unit.

Brian
Its odd though that it happens after the same distance travelled and then runs perfectly fine once it’s restarted. That’s what made me think of a fuel/water problem. Also, the temps vary more in the storage unit than in our attached garage at home. I thought that might increase the chance of condensation forming in the fuel system. I’m really at a loss on this one.

Last edited by Jstan2014; 03-06-2019 at 10:04 PM.
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Old 03-06-2019, 10:23 PM
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Is it possible that your choke is sticking closed and when it stalls and you restart it,(I assume you are pumping the gas pedal), that it unsticks and runs properly afterward? Just a thought. Good luck!
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Old 03-06-2019, 10:33 PM
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Originally Posted by 4corvettes View Post
Is it possible that your choke is sticking closed and when it stalls and you restart it,(I assume you are pumping the gas pedal), that it unsticks and runs properly afterward? Just a thought. Good luck!
Hmmm, that does sound possible. Yes, I pump the gas and it fires right up. That would unstick a stuck choke. When this happens next time (Iím sure it will) Iíll check and see if the choke is closed before I restart the engine. Thanks! I hadnít thought of this.
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Old 03-06-2019, 10:47 PM
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Thanks guys. I must sign off for the night. I’ll check back in the AM.
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Old 03-06-2019, 11:03 PM
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Two things come to mind.

1)Tank filter sock death. Sometimes this clogs the pump check valves too with sock debris.

2) Coil overheats. Ballast resistor overheats/condenser bad,
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Old 03-06-2019, 11:49 PM
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I just cleared out a mouse nest in the snorkel of our pickup.
Can't believe it had any power at all with that thing in it.
Take a look at the fuel inlet on your quad. Make sure that little filter is in there.
And here's something easy you can try...ÖÖ..
Loosen the fuel cap enough that air can get in the tank and go for a ride.
If that works you need to look at the charcoal canister lines etc.
good day...ÖÖ...
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Old 03-07-2019, 12:46 AM
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I think you are looking at either an intermittent electrical problem like a bad condenser or coil that fails when it warms up or a fuel restriction problem like a plugged fuel sock in the tank or the carb inlet filter. Dirt or rust in the tank that plugs up the filter sock with suction then allows flow after it has been shut down for awhile will do it. With a 72 you should actually be able to see the sock, pickup and any crud at the bottom of the tank with a flashlight.
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Old 03-07-2019, 03:11 AM
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Does your gas tank make a wooshing sound when you open the cap like air rushing in .
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Old 03-07-2019, 05:00 AM
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Originally Posted by Big2Bird View Post
Two things come to mind.

1)Tank filter sock death. Sometimes this clogs the pump check valves too with sock debris.

2) Coil overheats. Ballast resistor overheats/condenser bad,
Thanks for the input, Big2Bird. The sock is new and looks to be in great condition. Points, coil, and condenser are all new. Could an overheated coil react this way, after 1.2 miles, then restart and function without problems? It’s so odd.

Last edited by Jstan2014; 03-07-2019 at 05:03 AM.
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Old 03-07-2019, 05:02 AM
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Originally Posted by sug View Post
Does your gas tank make a wooshing sound when you open the cap like air rushing in .
No. Not at all.
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Old 03-07-2019, 05:07 AM
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Originally Posted by CanadaGrant View Post
I think you are looking at either an intermittent electrical problem like a bad condenser or coil that fails when it warms up or a fuel restriction problem like a plugged fuel sock in the tank or the carb inlet filter. Dirt or rust in the tank that plugs up the filter sock with suction then allows flow after it has been shut down for awhile will do it. With a 72 you should actually be able to see the sock, pickup and any crud at the bottom of the tank with a flashlight.
Thanks for the input, CanadaGrant. Maybe I got a bad new condenser or coil. Both have been replaced. The tank and fuel sock are new and crud free. The carb inlet filter is new, but I’ll check it.

Last edited by Jstan2014; 03-07-2019 at 05:10 AM.
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Old 03-07-2019, 05:23 AM
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Originally Posted by ramair_bryan View Post
I just cleared out a mouse nest in the snorkel of our pickup.
Can't believe it had any power at all with that thing in it.
Take a look at the fuel inlet on your quad. Make sure that little filter is in there.
And here's something easy you can try...……..
Loosen the fuel cap enough that air can get in the tank and go for a ride.
If that works you need to look at the charcoal canister lines etc.
good day...……...
Thanks ramair bryan. We’re clear of all rodents and nests. None found. I’ve tried the gas cap. (That was one of the first things I tried actually) I’ll check the fuel inlet filter. The previous owner removed the charcoal canister. Thanks again.

Last edited by Jstan2014; 03-07-2019 at 05:25 AM.
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Old 03-07-2019, 07:22 AM
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Originally Posted by Jstan2014 View Post
Thanks for the input, Big2Bird. The sock is new and looks to be in great condition. Points, coil, and condenser are all new. Could an overheated coil react this way, after 1.2 miles, then restart and function without problems? It’s so odd.
Yes. When it stalls , jump out and feel the coil. I have seen some hot as a pistol. The Red MSD coil likes to fail like that.

You might have debris in the pump causing the internal check valves to be clogged. OR, the formed "S" hoses are collapsing/bad.

Last edited by Big2Bird; 03-07-2019 at 07:23 AM.
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Old 03-07-2019, 07:25 AM
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I had a 72 here that would stall on left turns. A dizzy wire inside shorted on turns. VERY hard to find, but easily repaired.
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Old 03-07-2019, 08:06 AM
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Greetings from New Braunfels......my wife goes to Round Rock for work several times a month....

Replace the small 8" inch piece of rubber hose that goes from the gas tank sender to the fuel line. This can deteriorate and close off internally and because it is on the suction side.....cut off fuel to the pump. It may collapse just enough to only allow a trickle of gas through and when the float bowl is full it runs fine.....but when it can't keep up because of a partially blocked line.....it stalls. Wait 5-10 minutes and it starts right back up.......runs great.....go another couple of miles and kaput.
This is what happened to the car in my Avatar......it drove me nuts for a month til I was under it looking at stuff and took a chance removing that hose as I was out of options.......
After two fuel pumps.....insulating gaskets for the carb, shooting it with a $6000 thermal image scanner I borrowed ( which showed nothing out of the ordinary), a $1 piece of fuel hose fixed it....

Jebby

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Old 03-07-2019, 08:06 AM
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Originally Posted by Big2Bird View Post
Yes. When it stalls , jump out and feel the coil. I have seen some hot as a pistol. The Red MSD coil likes to fail like that.

You might have debris in the pump causing the internal check valves to be clogged. OR, the formed "S" hoses are collapsing/bad.
Roger that. Will do. Thanks. Iíve got a direction to go now and a few things to check.
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