[Frank V (Rtse)]

i have noticed a problem that appears when my engine is off idle there is a noticable miss in the engine(yes it does it stopped or going) though it still has alot of power, when i first put the engine together i wanted it to look like a stock points ignition so i used the pertronix ignition and it worked fine but it had the miss so i put in a chrysler performance ignition w/the orange box, still misses off idle so i hooked up a timing light and there is the miss what is wrong, the coil bad?(stock coil by the way, off a 383..whoops)i have talked to other mopar guys who think there is something out of balance inside the engine but if that were so wouldn't it idle badly too?(it purrs) this miss is just enough to make me think something is wrong inside the engine but something just doesn't add up my gut says to run out and buy a coil but figured i would try this board first any ideas are appreciated

[Dave-R (Roppa440)]

I can't think of any way a coil could do this. However it is easy enough to borrow a coil off another car to try so I would do that first.

You say that when you hook up a timing light you can see that it stops flashing at some point or misses flashes?

Or are you saying that the timing mark jumps around?

If the timing mark jumps around a LOT it is due to cross fire or something like that.

Also if the carb is not set at idle with the throttle blades closed enough it can cause a stumble during the idle-to-main transition. I have written something on setting the idle on here somwhere.

[Frank V (Rtse)]

it misses flashes about every 5 seconds,the carb is fine although it doesn't have the correct avs carb (i havent had luck finding one)it is an afb for now i talked to a mopar guy here last night who said he thought that you had to have a different coil for the mopar dist W/orange box,although if this were true you think they would include it in the kit you receive. i used to know how to check a coil to see if it was bad but it happens so rarely that i cant quite remember i also remember reading something about if cyl 1 wire and cyl 8 wires are to close to each other then a miss-fire can occur from one cyl trying to fire out of time but i also read that this can be death to an engine this is something i have been dealing with for awhile now also it seems the faster the car goes the better it runs(i can just see explaining that to the police...lol)...

[Dave-R (Roppa440)]

You can check the resistance of the windings in the coil.

Primary resistance = 1.41-1.79 ohms @ 70-80 deg F.

Secondary resistance = 9,200-11,700 ohms @ 70-80 deg F.

Other than that as long as it does not get too hot or have any cracks in it or dirt on it then it should be OK.

There is not a different coil for the electronic ignition.

Go to a yard and pull one off a wreck to try. Or borrow one from a friend. Just about any coil will work on any ignition as long as it does not have a built-in ballast resistor or something else non standard looking.

I would be inlined to suspect cross-fire in the leads or on the coil face or distributor cap.
Make sure your distributor cap and plug wires are clean/dry and keep the wires apart as much as possible.

Thats about the limit of what I know on the subject of coils. Let us know what the problem was when you find it.

[Dave-R (Roppa440)]

Just thought. You could try changing the plugs as well.

[Frank V (Rtse)]

thanks dave.. i will let ya know..

[John Macleod (Johnm)]

also check the pickup coil inside the distributor

they sometimes will not send the pulse to the control unit

[Ted S (Teds)]

bad aceleralotor pump.

[Frank V (Rtse)]

thanks, i will check these....i have found a wire that was slightly touching the exhaust manifold and though it didn't do any visible melting it has discolored the wire so i will change those the coil meets daves test requirements although when the engine misses every once in a while the reading on the ohm meter changes so i want to try hooking up a different coil just in case anyone have an extra one i could borrow?...lol (kidding)

[Dave-R (Roppa440)]

Err. Don't ever use a meter set to measure ohms on a live circuit. Always switch everything off. Resistance is mesured by passing a small battery voltage from the meter and through the wire. If there is electricity in the wire from another source you will not only get a false reading but you will damage the meter.

Every electrician I know has at some point in his life accidently put an ohm meter across live mains. I did this myself as a teenager. The resulting explosion was spectacular! What was more amazing was that my nuts were still intact because I had been sitting with the meter between my legs. One half of the plastic casing did just miss my head as well and made an impression in the ceiling.

[Frank V (Rtse)]

whoops... i will remember that!

[Frank V (Rtse)]

well it turned out the coil did have a leak and changing it stopped the misfire then i adjusted the a/f ratio just a bit - new plugs and wires and it is running great! ;D - thanks for all the help you guys gave....now off to find some victims..muuaahhahahahaha

[Frank V (Rtse)]

when i say the coil had a leak i meant voltage leak....lol