explosions on my 318..

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danval

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Ok, so im on the gas on my dart, 318/904.
Once i let the gas pedal go it starts throwing explosions down the headers, and the faster i go or the more gas i give, as soon as i let it go, the bigger the explosions are!!! :/
And it wont do it in neutral....
Is it timing or fuel mix? of both? thanks guys!
 
by "explosions" I am assuming you are getting some backfiring through the exhaust.

this can be cause by many things.

first you need to make sure your plugs are good and gapped correctly, good plug wires,cap and rotor,the rest of the ignition system need to be good (points,condensor,coil,blahblahblah).

make sure you have a good fuel filter,carb is properly tuned and is a good carb.

if it has a choke...make sure it is not close when warm and not open when cold.....it needs to function properly.

you need to pinpoint if its something that just happened out of the blue? or just after you got gas? (bad gas),or did you just pull it out of storage and you did not bother putting any type of water remover in the tank?,or does someone really dislike you and poured sugar in your tank? lol.

worn timing chain,worn valvetrain components such as lifters,cam,springs,valves and so on. does it puff blue or white smoke? over heat at all? could be a bad head gasket.

and one of the biggest things I can think of would be timing......your timing might be off if all the above is ok.

how many miles on the engine?,has it been sitting?,when did it start doing this? how long have you had it?

you need to give in depth information for an in depth accurate answer....otherwise a basic description will only get you as far as a basic answer.
 
DusterDude72 said:
by "explosions" I am assuming you are getting some backfiring through the exhaust.

this can be cause by many things.

first you need to make sure your plugs are good and gapped correctly, good plug wires,cap and rotor,the rest of the ignition system need to be good (points,condensor,coil,blahblahblah).

make sure you have a good fuel filter,carb is properly tuned and is a good carb.

if it has a choke...make sure it is not close when warm and not open when cold.....it needs to function properly.

you need to pinpoint if its something that just happened out of the blue? or just after you got gas? (bad gas),or did you just pull it out of storage and you did not bother putting any type of water remover in the tank?,or does someone really dislike you and poured sugar in your tank? lol.

worn timing chain,worn valvetrain components such as lifters,cam,springs,valves and so on. does it puff blue or white smoke? over heat at all? could be a bad head gasket.

and one of the biggest things I can think of would be timing......your timing might be off if all the above is ok.

how many miles on the engine?,has it been sitting?,when did it start doing this? how long have you had it?

you need to give in depth information for an in depth accurate answer....otherwise a basic description will only get you as far as a basic answer.
Click to expand...
My car had a slant six in it. After i finally killed it i decided to put the 318 in it.
I opened the 318 and it has new cam, new timechain, new lifters, pushrods, carburetor was completly rebuilt, new condenser, cap, sparkplugs, cables, fuel filter.
From what im thinking that could be reasons, these components are new. Now its not burning excessive smoke, or blue nor white.
I installed the motor at the end of january, with everything that i mentioned. I started doing it since i started driving, i messed a little bit with the a/f ratio and it went away very little, but im at the point where if i lean it more it will not be good. So my other option was timing... :roll:
Thanks!! :grin:
 
danval said:
My car had a slant six in it. After i finally killed it i decided to put the 318 in it.
I opened the 318 and it has new cam, new timechain, new lifters, pushrods, carburetor was completly rebuilt, new condenser, cap, sparkplugs, cables, fuel filter.
From what im thinking that could be reasons, these components are new. Now its not burning excessive smoke, or blue nor white.
I installed the motor at the end of january, with everything that i mentioned. I started doing it since i started driving, i messed a little bit with the a/f ratio and it went away very little, but im at the point where if i lean it more it will not be good. So my other option was timing... :roll:
Thanks!! :grin:
Click to expand...


easy enough to check
 
on deceleration, it backfires, but hauls good when you're on the gas, do you have an exhaust/header leak ?
 
It can be timing, too rich, or even lean.

Wiki says

"Backfiring can occur in carbureted engines that are running lean where the air-fuel mixture has insufficient fuel and whenever the timing is too advanced.

As the engine runs leaner or if there is less time for the fuel to burn in the combustion chamber, there is a tendency for incomplete combustion.
The result of a misfire or incomplete combustion is that unburned fuel or flammable hydrocarbons are delivered to the exhaust manifold where it may ignite unpredictably

Another backfire situation occurs when the engine is running rich (with excess fuel) and there is incomplete combustion during the Otto cycle, with similar results."

Hope this helps!
 
danval said:
Ok, so im on the gas on my dart, 318/904.
Once i let the gas pedal go it starts throwing explosions down the headers, and the faster i go or the more gas i give, as soon as i let it go, the bigger the explosions are!!! :/
And it wont do it in neutral....
Is it timing or fuel mix? of both? thanks guys!
Click to expand...

Vacuum leak maybe? When you let off on the gas vacuum rises way up until it goes back to idle. Try hooking a vacuum gauge up to the intake and check it at various throttle openings including full throttle. Could be a gasket.
 
I forgot to add that vacuum is even higher in gear when engine braking kicks in. That header leak idea sounds good though.
 
Repair the header leak, and noise will likely go away.. like demo cars backing-off at the speedway.. pop pop pop...bang
 
72Plymouth said:
It can be timing, too rich, or even lean.

Wiki says

"Backfiring can occur in carbureted engines that are running lean where the air-fuel mixture has insufficient fuel and whenever the timing is too advanced.

As the engine runs leaner or if there is less time for the fuel to burn in the combustion chamber, there is a tendency for incomplete combustion.
The result of a misfire or incomplete combustion is that unburned fuel or flammable hydrocarbons are delivered to the exhaust manifold where it may ignite unpredictably

Another backfire situation occurs when the engine is running rich (with excess fuel) and there is incomplete combustion during the Otto cycle, with similar results."

Hope this helps!
Click to expand...
hmmm and i described it as explonsions in the exhaust because i thought that backfiring was when the detonation goes back on the intake manifold up to the carb... Thank you! or cours it helps a lot! :D
 
rick360 said:
Vacuum leak maybe? When you let off on the gas vacuum rises way up until it goes back to idle. Try hooking a vacuum gauge up to the intake and check it at various throttle openings including full throttle. Could be a gasket.
Click to expand...
hmmm i didnt thought of this one... Ill definitely check this because i have one of those "pepboys" carb adapters...
 
Ok, ill look into this causes, specially the leak! thank you guys very much! this is great help!!!!
 
Repair the exhaust first, before spending much time with vacuum,, The fuel mixture still has to get thru the cylinders to explode in the exhaust...
 
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