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Discussion Starter · #1 ·
it's a 360, with an MSD ignition, holley carb, edelbrock performer RPM int. and hooker headers. It runs great everyday (except for trans. problems, diff. thread)
until it starts to precipitate in any shape or form, then it won't idle, it backfires through intake and exhaust, the carb loads up, so all I smell is raw fuel and it just runs really rough. Any suggestions? maybe a new carb.? thanks
 

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to me it sound like it could be electrical. Havent had this problem but have heard of it. Is there raw fuel comming out of the exhaust, if there is then the is a problem with the ignition system. Check the plug wires for a short that could be causing the backfiring.
 

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Aka Force Fed Mopar
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Sounds like a cracked distributor cap, letting moisture insde the distributor and causing arcing and misfiring.
 

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Speed Dragon said:
Sounds like a cracked distributor cap, letting moisture insde the distributor and causing arcing and misfiring.
Exactly what I thought.
 

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Go out at night and start the Dodge. Then lift the hood. With a DRY PLASTIC spray bottle start to spray the plug wires, moving from the plug to the distributor. As the mist hits the plug wires it surrounds the wires and you'll soon see if they're leaking energy. The same thing can be done with the distributor cap. If it is the cap the problem would have to be a Faint Arc Trail that would follow the coil wire to kill the engine completely, and not cause a cross fire. Also, look at the electrical connections to the Ignition Module to see if they're corroded.
 

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Discussion Starter · #6 ·
yeah, it has a brand new set of Taylor plug wires, and I changed the dist. cap, I also checked all of that above, and all seems well, no arcing etc. It only does this when it rains etc. I cannot figure it out. it's like the choke on the carb. is closed, but I've checked it 100 times and I know it opens. I am going to fabricate a plate that is semi water tight and completely seals the distributor from the weather, (here's my theory, I think the water is running down between the cowl and the hood and getting on the distrubutor, causing it to cross fire) and I will let you guys know what I find out. thanks, and any more suggestions are welcome.
 

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Where is the MSD module located??? On the fire wall or the Inner fender well???
If its mounted on the fire wall I'd bet thats the colprate... Not the distributor..

Second if your backfireing through the carb.... Its not healthy for your power valve & would cause wrough idle
 

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Aka Force Fed Mopar
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Yeah, it's definitely something ignition related getting moisture in it, or at least electrical.
 

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Mopar Madness - Get it...
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I don't know if they make it anymore, but back in the days of 'points' type of ignitions, they used to make this stuff (I believe... It's been 30+ years ago) called 'Ignition Dry' .... It was basically a little spray can of 'waterproofing' you'd spray on the distributor and other ignition electrical connections. Worked pretty well as I remember....
Might give that a shot, if they still even make it anymore....
 

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Discussion Starter · #10 ·
the MSD module is on the pass. fenderwell, still ahven't figured it out yet, I'll keep you guys updated.
 

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Aka Force Fed Mopar
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(here's my theory, I think the water is running down between the cowl and the hood and getting on the distrubutor, causing it to cross fire)
That sounds the most likely, either that or the MSD box is getting moisture in it somehow. Possibly the coil grounding or arcing when it's wet?
 

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When it acts up, spray the heck out of the MSD with WD-40...then try the inside of the cap or whatever else in the ignition system. Do one part at a time so you can find the problem. The WD-40 won't hurt anything. Sounds like a moisture problem for sure.
 

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Autoglass
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Sounds like the problem could be where the cowl drain is located! Look above the distributor cap, there is a little spout in the top of the firewall, what I did was make a rubber flap pop riveted to the air filter lid and laid over the distributor cap, it sure kept the water out of the cap for me. 5 Dodge Mechanics told me that was a neat trick! Feel like kicking myself for not taking photos of it! :VHOT:
 

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Discussion Starter · #14 ·
I fabbed some aluminum, screwed it to the firewall, so it covers the distributor, it has seemed to help a little. I need to get some pics for you guys.
 

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the raw fuel issue is one that intrigues me

I suspect that precipitation in any form as you put it is probably accompanied by lower temperatures; hence I suspect the choke may well be involved

With a carburetted engine, you would have to work some, in my opinion, to get enough raw fuel into the cylinders through cranking the started such that it would come out the tail pipe

So, I suspect serious flooding that might go along with some ignition related weather woes.

Sorry that I cannot offer more advice than to say have a good look at the choke and float settings in addition to making sure the ignition system stays dry

good luck
 

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Mopar Madness - Get it...
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Autoglass said:
Sounds like the problem could be where the cowl drain is located! Look above the distributor cap, there is a little spout in the top of the firewall, what I did was make a rubber flap pop riveted to the air filter lid and laid over the distributor cap, it sure kept the water out of the cap for me. 5 Dodge Mechanics told me that was a neat trick! Feel like kicking myself for not taking photos of it! :VHOT:
OK, here's a stupid question..... :D

Why would the Dodge Boys design the cowl drain, that drains right on top of the dist? They..... Can't be THAT stupid, could they? ;)
 

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Mopar Madness - Get it...
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Chump said:
When it acts up, spray the heck out of the MSD with WD-40...then try the inside of the cap or whatever else in the ignition system. Do one part at a time so you can find the problem. The WD-40 won't hurt anything. Sounds like a moisture problem for sure.
From seeing about your aluminum umbrella, I think Chump is steering you in the right direction. Water Displacement formula 40
(How many of you knew that? :D ) is a great starting point...

If you are indeed getting water into, whatever, that's why I pointed out the 'Ignition Dry' stuff (If they still make it)... It's like a Thompsons Water Seal for electrical components.
 

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Check the mounting of the MSD, it won't drain if mounted in certain positions if I recall correctly. Also run it at night to help check for spark leakage (arcing).
--B-300--
 

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Discussion Starter · #19 ·
the cowl drain is directly above the dist. on my truck, I have pulled the plug wires off the distributor and checked the contacts, well everytime I do it they're all blue with corrosion , so I take the dremel and clean em up, next time I check them same thing.I'll have to try the the WD-40 thing see if that helps as well, luckily the weather here has been dry, but cold so it's ran great.
 

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Mopar Madness - Get it...
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10cylinderRAM said:
the cowl drain is directly above the dist. on my truck,
Huh.... The Dodge Boys must have been smokin' dope the day they designed that.. I wonder how hard it would be drill and tap that hole, so you could install a little fitting with a hose nipple and piece of hose to direct the water away from the engine?
 
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