You rock supercharged. Thanks for taking the time to post this. This gives me a few things to check out
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| 5 volts at the coil on an a100? https://www.slantsix.org/forum/viewtopic.php?t=64468 |
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| Author: | lumbee [ Tue Feb 04, 2020 12:26 pm ] |
| Post subject: | 5 volts at the coil on an a100? |
Hey folks! 67 a100 van. Cold weather so only been starting it every couple of weeks to let it warm up. I noticed the last time I started it )about a month ago) it started kind of hard. Took a bit more turning over than usual for it start. Went out yesterday to start it and nothing...cranks over fine and stumbles a bit like it wants to start, but nothing. Verified I have gas/fuel (I see gas squirting down the carb throat when I press the pedal). I moved on to ignition/spark. I am measuring 5 volts at the coil. 12 in other places. The volts at the coil should be higher than that right? I checked my 71 Bug and it is showing 10v at the coil. |
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| Author: | wjajr [ Thu Feb 06, 2020 8:12 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Some things to look at: With key in run position yes 5 volts at coil is correct. Start circuit to coil should have nominal 12v just during cranking over of engine. First thing make sure all battery connections are clean and fast including ground to block, and fully charged. If this engine is using an ignition points distributor, check their condition and gap. Chances are they may have "burned"; that's a term used when arcing at points creates a non-conductive coating sometimes caused by condenser failure, or key left in run position when engine is not running. If engine starts and runs or almost starts, while starter is engaged, but shuts down the moment key is released and flips back to "Run" than ceramic resistor has failed. Resistor reduces 12v to 5v at coil. Coil may have failed, check by following one of these sites. Lastly battery may show 12 to 13.4 v and or no longer has enough reserve cranking amps to spin starter fast enough, and energize ignition system for engine to start. Charge battery, try starting engine, if it won't turn over engine or labors during cranking, have battery stress tested. Next is to make sure choke is in working order if the above is all good. Cold starts require a tightly closed choke butterfly during initial crank-over or A/F mixture won't be rich enough to start engine, and once engine lights-off butterfly should open about 1/4th inch and slowly fully open over several minuets of running. |
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| Author: | lumbee [ Thu Feb 06, 2020 10:46 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
You rock supercharged. Thanks for taking the time to post this. This gives me a few things to check out
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| Author: | lumbee [ Thu Feb 06, 2020 11:51 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Also, for posterity, good post here: http://www.slantsix.org/forum/viewtopic.php?t=56222 |
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| Author: | makapipi [ Thu Feb 06, 2020 8:17 pm ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Also since car only run for a little while once in awhile during cold temps. The spark plugs could be fouled up and cannot make good spark. That happened to me. |
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| Author: | Louise76 [ Sun Feb 09, 2020 9:03 pm ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
I agree with Makapipi. To me that's the most simple, and most likely. |
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| Author: | lumbee [ Mon Feb 10, 2020 7:02 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Yes...I did check the spark plugs right after it wouldn't start and they looked good...other than being drenched with fuel  Weather has been so cold I just couldn't bring myself to get out there and tinker with it. My first step was going to be put a spark tester on the wires and see how that looks. Also, check the voltage at the coil when starting and see if it jumps up to ~10volts. |
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| Author: | Louise76 [ Mon Feb 10, 2020 8:22 pm ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
"drenched with fuel", and maybe water condensation / ice, will short-out the plugs. That's why I would start there- most likely cause. |
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| Author: | wjajr [ Tue Feb 11, 2020 6:52 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Your cold weather is not the problem if choke is closing fully and ignition system is in spec. Lets see, wet plugs, compression, what's missing in this picture... Spark! These old heaps will start at -20*f, how do I know, I owned one for five years during early 70's in Maine, thirty years before global warming. A time when the big doom & gloom story was the coming ice age. |
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| Author: | lumbee [ Tue Feb 11, 2020 7:03 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
I agree wjajr. Plugs were "wet" but it was definitely fuel (not water). |
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| Author: | lumbee [ Tue Feb 11, 2020 9:58 am ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Well...it all seems to be much about nothing. I went to connect meter leads to the coil so I could measure the voltage when starting. The leads looked a little crusty I went ahead and removed the screws holding them in place and sort of rubbed them clean with my fingers (they really were not that dirty). Put the wires and screws back in place and proceeded to hook up the voltage meter leads. Went I went to start it BANG! its started right up. Sooooo...I'm calling it bad/loose leads for now. I think just retightening the screws holding the wires to the coils must have done the trick. Thanks all for help. |
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| Author: | Louise76 [ Tue Feb 11, 2020 4:46 pm ] |
| Post subject: | Re: 5 volts at the coil on an a100? |
Thanks for the feedback. It cures all of our speculations.
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