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Old 09-23-2019, 09:37 AM   #21
mb_camper
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Default Re: Weak Spark

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Originally Posted by mhsprecher View Post
With three jobs you are lucky to have any time at all. I have one more than full time job and it's a struggle to find time to work on cars. That said, if you have a can style coil AND a resistor, that is probably you problem. Wiser heads than mine can set you straight.
Are you saying that the resistor under the dash shouldn't be used with a can style coil? I plan on getting some resistance readings of my components today if all goes well.
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Old 09-23-2019, 09:49 AM   #22
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Default Re: Weak Spark

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Originally Posted by mb_camper View Post
It is a generic can style coil
It most likely does not need a resistor. Move the wire from the ignition switch to the resistor to the same terminal as the wire from the resistor to the coil. This will bypass the resistor. Make sure the ignition wire is connected to the (-) terminal on the coil and the (+) terminal on the coil is connected to the distributor.
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Old 09-23-2019, 11:32 AM   #23
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Default Re: Weak Spark

Some coils have an internal resistor. If you have a resistor under the dash and one in the coil that could be your problem. Examine the coil closely as some are marked regarding the internal resistor.
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Old 09-23-2019, 04:44 PM   #24
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Default Re: Weak Spark

The only way to really know is to measure the coil, but that said, almost all 6v coil have the required resistance because of the design of the windings. You want something around ~3.5 ohm of resistance and that is the range of most 6v coils.
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Old 09-24-2019, 03:24 PM   #25
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Ok, update time. I picked up another coil on the way home just in case, I checked resistance on the old coil on the primary side I had 1.6 ohms and 9k ohms on the secondary. the new coil measured 1.3 ohm primary and 9k ohms secondary which made me think both coils are fine. i did opt to install the new coil and jumped the resistor under the dash and have the best spark i have ever had in this car. that is the good, the bad is no matter what i do i cannot get the car started to save my life. i have checked spark, fuel, put no 1 cylinder on TDC and made sure the rotor is pointing straight down at number one plug wire, checked firing order to make sure one of my helpers didn't do me any favors all with no success. I did find allot of sediment in the fuel bowl and cleaned it out but i am confident that i am getting fuel (as a matter of fact it seems to be flooding). What am i missing? Just as a sidebar i pulled the firing order off for the internet and i looked at a couple of sites to make sure they were correct and on all of them they showed No 1 Plug wire at the 12 o'clock position on the distributor and mine is at 6 am i reading too much into this?
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Old 09-24-2019, 04:01 PM   #26
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Default Re: Weak Spark

Just to be sure, what are you calling the number one plug position on the engine and what firing order are you using?
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Old 09-24-2019, 04:21 PM   #27
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Default Re: Weak Spark

this is what i am going by, this drawing matches my dsto because it is viewed from the drivers side across the engine.
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Old 09-24-2019, 04:22 PM   #28
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Default Re: Weak Spark

i did confirm that this coil used an internal resistor before i jumped the under dash resistor.
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Old 09-24-2019, 04:49 PM   #29
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Default Re: Weak Spark

How did you determine you are at TDC on the start of the power cycle?
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Old 09-24-2019, 05:44 PM   #30
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Default Re: Weak Spark

I lined up the timing mark on the crank to the indicator on the block.
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Old 09-24-2019, 05:49 PM   #31
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Default Re: Weak Spark

That will not give you the correct position. On a 4 cycle engine there are 2 times the crank will line up with the indicator, and only one of them is correct. You have to assure that the piston is coming up on the compression stroke (both valves closed). The engine will only fire properly when the engine is on the correct cycle.

Remove the number one spark plug and rotate the engine until you can fill the compression and align the timing marker on that cycle. The diagram has overhead valves, but the engine cycles are the same.
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Old 09-24-2019, 06:12 PM   #32
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Default Re: Weak Spark

I did do that when I first got the car to get it running initially. Remember the car was running quite well with only a slight flutter on my vacuum gage tapped into the intake just 2 days ago. Then I jumped the - on the coil to the - battery post. It died and thatís the last time it ran.
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Old 09-24-2019, 06:23 PM   #33
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Default Re: Weak Spark

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Originally Posted by mb_camper View Post
Are you saying that the resistor under the dash shouldn't be used with a can style coil? I plan on getting some resistance readings of my components today if all goes well.
I was having starting problems with my 38, running a 49-53 round coil, called Dick FLYNN, he said to bypass the resister under dash, did that a few years ago, will always start even when hot, puts 6 volts to coil, no point problems
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Old 09-24-2019, 06:28 PM   #34
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Default Re: Weak Spark

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Originally Posted by mb_camper View Post
I did do that when I first got the car to get it running initially. Remember the car was running quite well with only a slight flutter on my vacuum gage tapped into the intake just 2 days ago. Then I jumped the - on the coil to the - battery post. It died and that’s the last time it ran.
So nothing has changed with the distributor and the timing since the last time it was running? If so and you have a spark and fuel and compression it should fire. Have you tried something like starter fluid? A small squirt should tell you if the plug is firing in the cylinder.

By the way, there is always what is considered a correct position and plug wire arrangement on a distributor. It doesn't really matter IF you understand what your doing and are sure you have the rotor aligned with the correct terminal on the cap for the #1 plug wire and the other wires installed correctly from that starting point.
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Old 09-24-2019, 07:40 PM   #35
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Default Re: Weak Spark

Exactly, now you see my dilemma. The only thing that changed in the distributer was a slight adjustment to line up the rotor to number one (less than 1/4 inch rotation) and only after I confirmed I was getting both fuel and spark. I am getting a nice blue spark at the points and a good spark at the plug. I pulled the plugs and the were wet with gas. Dried, cleaned checked compression and replace each plug. Confirmed firing order again still only coughs and tries to catch but never does.

That was always my understanding as well when it comes to plug wires, I just wanted to make sure I wasn’t missing something.
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Old 09-25-2019, 03:27 PM   #36
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Default Re: Weak Spark

Ignition condensers form an important part of the system. If they become weak or open, the spark will be severely diminished because the coil can't fully recharge between point cycles. We seem to be having a big problem with the quality of replacement condensers
today, almost all foreign made. If you are doing a routine tune up. and the engine is running OK, reusing the condenser is preferable to new non US made. I carry a spare condenser in my "road kit". I has clip leads on it and can be quickly installed connecting the leads between ground and the input terminal to the coil.
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Old 09-25-2019, 04:00 PM   #37
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Default Re: Weak Spark

Just a thought,is the capacitor on the point side of coil! You said it hasn’t run after changing wires on the coil,
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Old 09-27-2019, 07:25 PM   #38
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Talking Re: Weak Spark

Problem solved! Weak ignition condenser. Thanks to all of you who are willing to share your knowledge, I am glad I found this forum!
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Old 09-27-2019, 08:39 PM   #39
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Default Re: Weak Spark

Looks like Supereal and Don nailed it!
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