Okay, I've got 13 volts going into the coil, I just don't know what's coming out of the coil. I have one of those testers that plugs in between the spark plug and the wire. We'll see what happens next!
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| Weak Ignition, I think... https://slantsix.org/forum/viewtopic.php?t=47583 |
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| Author: | Wesola78 [ Sat Jan 14, 2012 8:05 pm ] |
| Post subject: | Weak Ignition, I think... |
Okay, so I put in new plugs a couple of weeks ago, the ones I took out were fouled. However, it just feels to me like the ignition is not doing it's job. I have not checked anything out with my multimeter yet, but I am going to. A friend told me to check the voltage at the ballast resistor. He also said that the coil might be going out. So, I am going to do some checking. I have an Accel coil on there now, it's a few years old. I have a few stock Mopar coils in my garage that I could try. The wires don't look bad, but it is all pretty much original (old) wiring. Any tips on what else I should look at? Thanks in advance! Onward... |
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| Author: | Aggressive Ted [ Sat Jan 14, 2012 8:32 pm ] |
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Checking voltage on each side of the ballast is a good place to start. Should be a full 12 volts on one side the other side will very from 6 to 8 volts. What ever it is write it down then go see what it says at the coil. It should read the same voltage. If not then the bulkhead connectors may not be so good or the engine harness may be melted that runs along the valve cover. The alternator wire on mine had melted and fused with the temp sender and oil sender...... |
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| Author: | WagonsRcool [ Sat Jan 14, 2012 9:17 pm ] |
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If you think ignition isn't up to snuff, confirm it before you start replacing parts. Use a spark tester like Thexton #458 ($21 at Amazon). Connect it into the end of a plug wire, clip on ground wire & start engine. (carefully) turn out the thumb screw to see how big a gap the ignition can jump. You want a nice blue spark, at least 1/2" gap. If the spark is dull yellow or "goes away" at 3/8" or so, then you can diagnose the problem. |
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| Author: | Wesola78 [ Sun Jan 15, 2012 3:46 pm ] |
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Okay, I've got 13 volts going into the coil, I just don't know what's coming out of the coil. I have one of those testers that plugs in between the spark plug and the wire. We'll see what happens next!
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| Author: | terrylittlejohn [ Sun Jan 15, 2012 4:40 pm ] |
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were are you grounding the test meter? if you want coil voltage check across the coil +&-, chassis ground & + coil will give you voltage to the coil. |
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| Author: | Wesola78 [ Sun Jan 15, 2012 7:34 pm ] |
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Quote: if you want coil voltage check across the coil +&-,
Okay, actually, that's what I did. So, I've got 13 volts coming out of the coil?Thanks for the FYI! |
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| Author: | Sam Powell [ Mon Jan 16, 2012 5:02 am ] |
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I no longer have an ignition that requires a ballast resister, but my understanding was that the coil was supposed to have the same voltage as the low side of the ballast resister. Can anyone substantiate that? I am wondering if you have the ballast resistor wired backwards. Check the voltage going into your ignition box. That should be the full 13.5 or whatever your alternator puts out. Sam |
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| Author: | Sam Powell [ Mon Jan 16, 2012 5:03 am ] |
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Quote: If you think ignition isn't up to snuff, confirm it before you start replacing parts. Use a spark tester like Thexton #458 ($21 at Amazon). Connect it into the end of a plug wire, clip on ground wire & start engine. (carefully) turn out the thumb screw to see how big a gap the ignition can jump. You want a nice blue spark, at least 1/2" gap. If the spark is dull yellow or "goes away" at 3/8" or so, then you can diagnose the problem.
I have never heard of these. What a great idea. Where have I been? I'm getting one.Sam |
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| Author: | wjajr [ Mon Jan 16, 2012 6:14 am ] |
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Wesola78, I’m not sure how electrical you are, so forgive me if this explanation is on the basic side. Whatever voltage you have at the low side of ballast resistor should be the same reading on + side of coil within a few hundredths of a volt. 13 volts is way out of line for stock coil, (should be around 5-6 volts). Something goofy is going on. Recheck the following tests with black lead of VOM on battery negative terminal with engine running (make a long jumper if leads are not long enough to reach battery): 1. Ignition switch side of ballast resistor (this would be high side looking for 13.8 v to 14.5 v) 2. Coil side of ballast resistor (looking for 5 v to 7 v, this side connects to + side of Coil) 3. Negative side of coil Testing coil: Now with engine off, disconnect coil from electrical harness, switch VOM to DC Ohms 200 ohm or less setting, (Greek letter omega, horse shoe symbol on meter) First test: check Primary side of coil, or its low voltage circuit. Place black VOM probe on (-) and red on (+), reading should be about 0.75 to 0.81 ohms Secondary side of coil, or its high voltage circuit: Second test: change VOM Ohm scale to read 20K. Place one probe into center hole of coil, the other on (+) terminal the reading should be 10,000 to 11,000 ohms. Let us know what you get for readings |
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| Author: | Wesola78 [ Mon Jan 16, 2012 11:35 am ] |
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wjajr, thanks very much for your input. I know a little about electronics, but don't worry about being too basic with me. Per your advice, I will check it out with my meter. Thanks again! |
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| Author: | Wesola78 [ Mon Jan 16, 2012 12:04 pm ] |
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"2. Coil side of ballast resistor (looking for 5 v to 7 v, this side connects to + side of Coil)" I just did this one. With the neg probe lead on the neg side of the battery, and the pos probe lead on the pos side of the coil, a bit over 9 volts. I will continue checking... |
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| Author: | KBB_of_TMC [ Mon Jan 16, 2012 1:35 pm ] |
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I'd also like to suggest you replace the coil, as I've seen many coils get flaky after > 1 billion sparks. Internal secondary breakdown is quite hard to see w/o a scope. |
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| Author: | Wesola78 [ Mon Jan 16, 2012 8:08 pm ] |
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Do any of you guys favor the MSD Blaster 2 coil? Or a more OEM type of coil? |
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| Author: | Aggressive Ted [ Mon Jan 16, 2012 11:17 pm ] |
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OEM or Pertronix, the MSD coil is now made in China. Wes, Click on the red link below my name. Take a look at the Pertronix 60,000 volt HEI coil I am running. It is is built very well and I purchased the 3 ohm version so I could toss the ballast resistor. Their engineers have been very helpful. They make standard coils as well in many ohm ratings. Take a look at their website www.pertronix.com |
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| Author: | Sam Powell [ Tue Jan 17, 2012 4:17 am ] |
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Ted, Would that be the Flame thrower HV? I do not see HEI mentioned in the text for it. But it did say it was 60,000 volts. When I looked up the flame thrower HV on JEGS they listed three of them: .45 ohms, 1.5 ohms and 3 ohms. What is the impact of this choice? HOw does one know which one to get? Do you think the Second Strike ignition would be a serious upgrade over a new MSD? It is almost $200 more. The specs certainly looks impressive. Does anybody discount this? Edited note: I just found it on Amazon for $80 less. Sam |
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