Slant Six Forum :: Another coil question

...I had a new coil and orange ignition module on the shelf, so I swapped those in so far.

Quote:

...I had a new coil and orange ignition module on the shelf, so I swapped those in so far.

By new do you mean actualy "new" as in purchased recently from the parts store? If so, the Chinese made ignition modules you can buy these days are known to commonly be bad out of the box. That might be your problem right there.

Can I check the amperage coming from the the coil to the distributor with a multi-meter, or is it off the scale?

Quote:

Can I check the amperage coming from the the coil to the distributor with a multi-meter, or is it off the scale?

No.....There's very little amperage on the ignition secondary circuit anyway. It's high voltage, in the order of 6,000- 8,000 volts (stock) that bridges the spark plug gap and makes the spark, and would probably kill most meters. The color of your current spark should be enough to cause ignition of a fuel/air mix under pressure.
You need air, fuel in the right proportions, and spark, at the right time, in order to make the engine run.
Is the spark you have actually getting to the plugs?
How confident are you that the timing is good?
Might the distributor clamp have loosened and allowed the distributor to turn?
Is your timing chain and sprockets in good enough condition yet?

Roger

If you can find an original used or a NOS ignition module, try and run it.

Do you have spark now? Did you adjust the valve lash? That is a classic, and fits your symptoms...

Lou

Author:	slantfin [ Tue Feb 04, 2020 1:26 pm ]
Post subject:	Another coil question
I'm trying to figure out a no-start condition on my slant six. The starter cranks OK, fairly new battery with 13 volts across terminals, but no start, even with a shot of ether, nothing. I'm only getting 5 volts at coil positive, which seems too low. What should it be? Thanks for your reply.

Author:	Dart270 [ Tue Feb 04, 2020 2:42 pm ]
Post subject:	Re: Another coil question
5 Volts might be due to the ballast resistor voltage drop, although that seems too low to me. First thing is to check for spark at the plugs. Pull a plug wire and put a screwdriver in the plug wire terminal, then hold the screwdriver shaft about 1/8 - 1/4" from a good ground. Put the key in the ON position and then crank the engine over. You should see a spark jumping from the screwdriver to ground, even with 3/16" or a bit more gap between the two. If not, you are not getting any spark to start and run the engine. If no spark there, start tracing things backwards. Pull the "high tension" wire that goes into the top of the coil and do the same test with the screwdriver and cranking over the engine. We can go from there... Did you change anything else before this, like points or timing or??? Lou

Author:	slantfin [ Wed Feb 05, 2020 7:21 am ]
Post subject:	Re: Another coil question
Initially the car began to die at idle, and finally wouldn't start at all. I had a new coil and orange ignition module on the shelf, so I swapped those in so far.

Author:	Dart270 [ Wed Feb 05, 2020 7:53 am ]
Post subject:	Re: Another coil question
Do you have spark now? Did you adjust the valve lash? That is a classic, and fits your symptoms... Lou

Author:	Reed [ Wed Feb 05, 2020 8:49 am ]
Post subject:	Re: Another coil question
Quote: ...I had a new coil and orange ignition module on the shelf, so I swapped those in so far. By new do you mean actualy "new" as in purchased recently from the parts store? If so, the Chinese made ignition modules you can buy these days are known to commonly be bad out of the box. That might be your problem right there.

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Author:	slantfin [ Wed Feb 05, 2020 2:16 pm ]
Post subject:	Re: Another coil question
I have spark, but I haven't investigated how much since the coil swap. My truck failed its safety inspection, so that took me off the project car. The truck now has new torsion bars, upper control arms and a valid legal sticker for one year. I'll investigate the spark when I get time to go back out there.

Author:	slantfin [ Wed Feb 26, 2020 1:08 pm ]
Post subject:	Re: Another coil question
Sorry for the big pause, weather, job, truck repairs... Still have crank but no start, even with a shot of ether. I managed to test for spark at the coil, and have a yellow-orange spark coming from the wire that would go to the center of the distributor cap. I might do a cold valve adjustment in case that's way off. It's been a few years since I did a hot adjustment. Other than that, what would I do next?

Author:	slantfin [ Wed Feb 26, 2020 1:18 pm ]
Post subject:	Re: Another coil question
Quote: Quote: ...I had a new coil and orange ignition module on the shelf, so I swapped those in so far. By new do you mean actualy "new" as in purchased recently from the parts store? If so, the Chinese made ignition modules you can buy these days are known to commonly be bad out of the box. That might be your problem right there. I'm not sure about where they were made. I think I got them online, so may be sketchy. Is there a recommended brand available? I have some used ones that came with my replacement /6. They seem like they would be hard to bench test, no? Especially considering operating temperature and conditions. Not too pro at electronics.

Author:	Reed [ Wed Feb 26, 2020 7:16 pm ]
Post subject:	Re: Another coil question
If you can find an original used or a NOS ignition module, try and run it.

Author:	volaredon [ Thu Feb 27, 2020 4:29 pm ]
Post subject:	Re: Another coil question
a lot of the 80s trucks came from the factory with ignition modules that were orange, but they aren't the high performance ones that were so highly sought after at one time.... and the MP "orange boxes" certainly aren't what they used to be

Author:	slantfin [ Tue Mar 03, 2020 5:56 pm ]
Post subject:	Re: Another coil question
Can I check the amperage coming from the the coil to the distributor with a multi-meter, or is it off the scale?

Author:	GTS225 [ Wed Mar 04, 2020 5:06 am ]
Post subject:	Re: Another coil question
Quote: Can I check the amperage coming from the the coil to the distributor with a multi-meter, or is it off the scale? No.....There's very little amperage on the ignition secondary circuit anyway. It's high voltage, in the order of 6,000- 8,000 volts (stock) that bridges the spark plug gap and makes the spark, and would probably kill most meters. The color of your current spark should be enough to cause ignition of a fuel/air mix under pressure. You need air, fuel in the right proportions, and spark, *at the right time*, in order to make the engine run. Is the spark you have actually getting to the plugs? How confident are you that the timing is good? Might the distributor clamp have loosened and allowed the distributor to turn? Is your timing chain and sprockets in good enough condition yet? Roger

Author:	slantfin [ Wed Mar 04, 2020 7:44 am ]
Post subject:	Re: Another coil question
Quote: Quote: Can I check the amperage coming from the the coil to the distributor with a multi-meter, or is it off the scale? No.....There's very little amperage on the ignition secondary circuit anyway. It's high voltage, in the order of 6,000- 8,000 volts (stock) that bridges the spark plug gap and makes the spark, and would probably kill most meters. The color of your current spark should be enough to cause ignition of a fuel/air mix under pressure. You need air, fuel in the right proportions, and spark, *at the right time*, in order to make the engine run. Is the spark you have actually getting to the plugs? How confident are you that the timing is good? Might the distributor clamp have loosened and allowed the distributor to turn? Is your timing chain and sprockets in good enough condition yet? Roger When the problem began, it was mid-summer, a hot day. The car started to stall out at lights, and got progressively less inclined to run, and finally wouldn't start at all. Timing chain is fairly recent. I haven't checked the distributor hold-down, but I will today.

Author:	slantfin [ Wed Mar 04, 2020 7:46 am ]
Post subject:	Re: Another coil question
Quote: If you can find an original used or a NOS ignition module, try and run it. I have some used ones that came with the engine, the guy was getting rid of his slant parts. I'll try another one.

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Author:	slantfin [ Thu Mar 19, 2020 4:25 pm ]
Post subject:	Re: Another coil question
Quote: Do you have spark now? Did you adjust the valve lash? That is a classic, and fits your symptoms... Lou It seems like I have enough spark, from what GTS225 says. When you say classic valve lash situation, do you mean that it goes out of adjustment, or that it would be caused by an improper adjustment? Because as I mentioned earlier, I haven't done a valve lash adjustment for a long while. I'll check it in any event once the weather improves.