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Cooling issue (revisited) #2697769
09/15/19 02:04 PM
09/15/19 02:04 PM
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Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
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Scott Carl  Offline OP
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So I had a post a while back about a cooling issue on my 74 Challenger, 318/904 car mild cam, cast iron 4bbl manifold, Carter AVS, Magnum exhaust. With 2 core aluminum aftermarket radiator, I couldn't keep it under 220 - 230*. Switched to a 3 core and I can run 200 and under even with a 180* thermostat. However, after about a half hour run, (Good and warmed up), it starts crapping out at WOT, stalling at stops and hard to re-start. I believe its fuel starved. It starts long enough for the started to quit turning then dies. After several attempts it will start but run but erratically. Misses and runs rough at anything over an idle until its cool again.

Question: Will a weak fuel pump act this way when it gets hot? Carb too hot and boiling fuel in bowl? Timing issue; Weak advance springs? Runs great at first but tends to feel starved at WOT

Thanks
Scott

Re: Cooling issue (revisited) [Re: Scott Carl] #2697783
09/15/19 03:05 PM
09/15/19 03:05 PM
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Andrewh Offline
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not likely a fuel issue.
since it will run for a while normally first.

you probably have an ignition issue.
but you can test yourself, by manually using a lower gear so you have higher rpm than normal and try wot say in first gear. see if you still have it early before it heats up.
if it doesn't do it, then it isn't fuel.

Re: Cooling issue (revisited) [Re: Scott Carl] #2697787
09/15/19 03:27 PM
09/15/19 03:27 PM
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Posts: 36,040
Lincoln Nebraska
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RapidRobert Offline
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Scott what ign do you have?


live every 24 hour block of time like it's your last day on earth
Re: Cooling issue (revisited) [Re: Scott Carl] #2697837
09/15/19 06:59 PM
09/15/19 06:59 PM
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Omaha Ne
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TJP Offline
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Quote
it starts crapping out at WOT, stalling at stops and hard to re-start. I believe its fuel starved. It starts long enough for the started to quit turning then dies. After several attempts it will start but run but erratically. Misses and runs rough at anything over an idle until its cool again.


Sounds a bit like vapor locking but could be a heat sensitive ignition component as well. You're not running ethanol based fuel are you ?? beer

Re: Cooling issue (revisited) [Re: RapidRobert] #2697870
09/15/19 08:49 PM
09/15/19 08:49 PM
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
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Scott Carl  Offline OP
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Originally Posted by RapidRobert
Scott what ign do you have?


Robert, its just a stock ignition

Re: Cooling issue (revisited) [Re: TJP] #2697871
09/15/19 08:52 PM
09/15/19 08:52 PM
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
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Scott Carl  Offline OP
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Originally Posted by TJP
Quote
it starts crapping out at WOT, stalling at stops and hard to re-start. I believe its fuel starved. It starts long enough for the started to quit turning then dies. After several attempts it will start but run but erratically. Misses and runs rough at anything over an idle until its cool again.


Sounds a bit like vapor locking but could be a heat sensitive ignition component as well. You're not running ethanol based fuel are you ?? beer


Yes, actually I do tend use ethanol

Re: Cooling issue (revisited) [Re: Scott Carl] #2697885
09/15/19 09:14 PM
09/15/19 09:14 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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RapidRobert Offline
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Originally Posted by Scott Carl
Originally Posted by RapidRobert
Scott what ign do you have?


Robert, its just a stock ignition
That's good news. Was it acting up when you had the cooling issue?


live every 24 hour block of time like it's your last day on earth
Re: Cooling issue (revisited) [Re: RapidRobert] #2697896
09/15/19 09:30 PM
09/15/19 09:30 PM
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
pro stock
Scott Carl  Offline OP
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Posts: 1,568
Omaha, Nebraska
Originally Posted by RapidRobert
Originally Posted by Scott Carl
Originally Posted by RapidRobert
Scott what ign do you have?


Robert, its just a stock ignition
That's good news. Was it acting up when you had the cooling issue?


Yes. I assumed at that time, it was a heat related issue. In fact, with the 2 core radiator, on a couple occasions, it seemed to get so hot, it shut down and wouldn't restart for a couple hours. BTW, I have a new temp gauge, finally. The old one was sticky and never did go all the way to 0*

Re: Cooling issue (revisited) [Re: Scott Carl] #2698780
09/18/19 07:44 PM
09/18/19 07:44 PM
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TJP Offline
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Originally Posted by Scott Carl
Originally Posted by TJP
Quote
it starts crapping out at WOT, stalling at stops and hard to re-start. I believe its fuel starved. It starts long enough for the started to quit turning then dies. After several attempts it will start but run but erratically. Misses and runs rough at anything over an idle until its cool again.


Sounds a bit like vapor locking but could be a heat sensitive ignition component as well. You're not running ethanol based fuel are you ?? beer


Yes, actually I do tend use ethanol


Ethanol based fuels have a lower boiling point than non ethanol fuels and can wreak havoc in older carbureted vehicles with the temperatures we've been experiencing. \
I would start by getting it out of the system ASAP. Other changes may also be required if it is vapor lock and changing fuel does not resolve the issue. beer

Re: Cooling issue (revisited) [Re: TJP] #2698822
09/18/19 11:30 PM
09/18/19 11:30 PM
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl Offline OP
pro stock
Scott Carl  Offline OP
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Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Just to eliminate the ignition system:
The only thing I could move is the coil. Everything else is on the firewall. Any advantage to having these components on a fender-inner instead of the firewall?

Scott







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