347 Keeps Dying Randomly

289 - 351 cid Small Block Performance
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kyudizky
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347 Keeps Dying Randomly

Post by kyudizky »

My '64 with a 347 in it keeps dying while driving. Will idle perfectly fine, but once I get up to speed it just dies. I can pop the clutch in and turn the key and it fires right back up. Replaced the starter cable and and couple of other cables that had cracked insulation thinking it might be shorting somewhere, and I have a vented gas cap but even tried it without it on in the event that is wasn't venting properly to no avail.

Any ideas?

Its got a electric fuel pump just after the tank. Thought about trying to replace the pre-filter on it in case it was clogged, or even bad fuel, but it doesn't really act like its fuel starved and will crank right back up.

Thankfully I was able to just keep re-cranking it to get back to the house, although in a miles span it died several times.

Any help would greatly be appreciated!

-Kyle

pfleuret
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Re: 347 Keeps Dying Randomly

Post by pfleuret »

Happened me long time ago. Was a clogged fuel filter near the carburetor.
Pat

1963 1/2 S-22 260/4spd


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kyudizky
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Re: 347 Keeps Dying Randomly

Post by kyudizky »

I also tried replacing the coil... no luck either

I have a new little 40 micron prefilter being delivered tomorrow since its cheap and easy to replace to see if it helps...

A/FX
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Re: 347 Keeps Dying Randomly

Post by A/FX »

This maybe a long shot but I have heard about guys having this happen. Something foreign in the fuel tank plugs the pickup which starves the engine of fuel. As soon as the pump stops ( engine not running) the suction stops and the foreign piece moves away from the pickup until it makes its way back to the pickup and it starts all over again.
Also check the carb float level. Do you have points or Pertronix? Did you change the condenser? Pertronix modules do fail, I always carry a spare with me.
Good Luck!
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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poboyjo65
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Re: 347 Keeps Dying Randomly

Post by poboyjo65 »

if you could narrow it down to fuel or fire would be good. . might check fire next time it stops . If all mentioned above doesn't help ,,,,if it still has the original tank that would be my number one suspect. I dont really like running them full time but the el cheapo clear plastic filters are good to watch fuel travel & dirt . what Jim said about the pertronix or points/condenser >> When I got my car it would do me same way. seemed like if you gave it a lot of throttle,like half - 3/4 throttle it would die. after a few minutes it would crank. but if you took off gentle & stayed under 55 or so it was ok. I put a one wire hei with built in coil & it ran like top so I never was sure whether it was coil or the pertronix so I didnt reuse either one.
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kyudizky
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Re: 347 Keeps Dying Randomly

Post by kyudizky »

My car has a MSD 6A ignition controller with a MSD distributor. No pertronix or points, no condenser. And in all honestly I am relatively unfamiliar with ignition boxes in general, it was on it when I bought the car.

Got the little fuel pump pre-filter in today and will put it on this weekend and if that doesn't work I'll put a glass filter that I have laying around in place of the pre-carb filter thats on it now.

I cranked it tonight, never put it in gear, and after a few minutes of letting it warm up it would die. As usual, will crank right back up no problem, then just die again while rev'ing it still (was still having to rev it to get it warmer before it will idle on its own). Its seams like the situation is getting worse and worse and dying sooner each day I additional day I have cranked it up since its started happening.

A/FX
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Re: 347 Keeps Dying Randomly

Post by A/FX »

You definitely need to determine if it is fuel or an ignition issue, otherwise you are shooting at a moving target. Rig up a fuel line to a gas can or similar and bypass the stock tank and lines. ( could be a rubber line collapsing)
I am not familiar with MSD systems, maybe someone else can jump in and suggest a test for that.
Jim
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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poboyjo65
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Re: 347 Keeps Dying Randomly

Post by poboyjo65 »

This spark tester might be pretty cool in this situation. for the price I might pick one up next time I'm in there or make an order,,,, if I can think of it ,,,& put it in the glovebox
https://www.harborfreight.com/in-line-s ... s4QAvD_BwE
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Johno

saSSoman8810
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Re: 347 Keeps Dying Randomly

Post by saSSoman8810 »

Most MSD boxes have a little light on them. If the light is out then no fire. Go on the MSD website, there is a trouble shooting guide. Could be the pickup in the dist or the box itself.
Sounds like a loose or corroded connection or a fuel starvation issue.

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Jims65cyclone
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Re: 347 Keeps Dying Randomly

Post by Jims65cyclone »

poboyjo65 wrote:
Fri Feb 23, 2024 1:07 am
This spark tester might be pretty cool in this situation. for the price I might pick one up next time I'm in there or make an order,,,, if I can think of it ,,,& put it in the glovebox
https://www.harborfreight.com/in-line-s ... s4QAvD_BwE
I have one of those. They come in real handy for checking spark on cars and on small engines like lawn mowers, etc.

Jim
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