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Old 09-03-2016, 06:12 PM
jjs jjs is offline
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Question Voltage problem dist

I have a Daves small body dist. that works fine. I replaced the stock coil resistance wire with
a 12v feed. The car runs fine for the last five years. I bought a innovate mtx-l a/f gauge. I also bought a painless 3 circuit fuseblock to clean things up. The plan was to replace the 12v coil feed and power the mtx-l. Changed the12v coil feed to the new fuseblock and the car back fired and would not start. Went back to the old 12v feed and it started up. The voltage on the old feed is about 12.3 volts. The voltage off the new fuseblock is 14.5v. Ran a wire from the batty 14.5v to the coil and car would not start, back fired. The dist. is Dave hei conversion, should the dist work with 14.5 volts thats the out put of the alternator also? I believe that stock hei use 14.5v. I do not what module he uses. His web site is down.

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Old 09-05-2016, 12:49 AM
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gtofreek gtofreek is offline
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That makes no sense as the distributor should run better on 14.5 volts compared to 12.3. Never seen that before.

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Old 09-05-2016, 08:44 AM
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Might have an over-voltage protection circuit?


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Old 09-05-2016, 11:07 AM
jjs jjs is offline
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Question

Maybe the coil is the problem, using an accel super stock 8140? Don't know the specs for this coil? Will try to get in touch with Dave of Small base dist. maybe the module does not handle that voltage. Also now worried that the mtx-l will have a problem.

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Old 09-05-2016, 06:18 PM
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The difference in voltage has me puzzled. Kinda like the resistance wire is/was still there. So did you run a new wire from the switch out or replace a section of wire under the hood and/or under the dash when you did the original bypass?

On the 69 it looks like IGN-1 (run resistance wire) and IGN-2 (12 volts cranking) are both under the dash.

When you did this last wire change did you hook IGN-2 back up? Without IGN-2 hooked up, there wont be any volts for starting BUT the coil will fire when you let off the switch to run position.

The small didtributor should work on system voltage or at least I think it should. Most aftermarket coils use a ballast resistor or factory resistance wire, even with electronic triggers.

Just a few things you need to check out
Clay

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Old 09-06-2016, 10:10 AM
jjs jjs is offline
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The bottom line is why the engine won't run on 14.5 volts even directly from batty. It must be the module. I think dave uses the hei module but not sure. Need to get in touch with him.
Any suggestions or tests is appreciated.

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Old 09-06-2016, 10:43 AM
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Do you have a diagram of how the distributor is supposed to be wired?

Also, you are connecting the power (12 or 14.5) to the coil correct?


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Old 09-06-2016, 01:52 PM
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Quote:
Originally Posted by jjs View Post
Changed the12v coil feed to the new fuseblock and the car back fired and would not start. Went back to the old 12v feed and it started up. .
Quote:
Originally Posted by "QUICK-SILVER" View Post
Most aftermarket coils use a ballast resistor or factory resistance wire
Quote:
Originally Posted by jjs View Post
The bottom line is why the engine won't run on 14.5 volts even directly from batty. It must be the module. I think dave uses the hei module but not sure. Need to get in touch with him.
Any suggestions or tests is appreciated.
Too much voltage to the coil, not too much voltage to the module if it's a 4 pin GM.

Some coils have built in resistance while others don't. Just because you hook battery to a coil doesn't mean it's going to work. Coils that need a ballast resistor or resistance wire WILL NOT fire like they're suppose to without the primary resistance.

With your voltage difference, it sounds like your resistance wire is still in the circuit.

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Old 09-06-2016, 07:00 PM
jjs jjs is offline
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The 12.3v wire is 12.3v on the coil while the engine is running. This is not a resistance wire. Hei do not need a ballast resistor, this only reduces the voltage to the coil. GM hei did not use one as far I know. ballast resistors were used so the points would not burn up. The 14.5v from the batty is with the car running, the alternator output. This is also the tap for the three circuit fuseblock. I am going to change coils tomorrow

  #10  
Old 10-05-2019, 01:36 PM
David Ray David Ray is offline
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Old topic, I am brand new here.

Yes, one of my conversions should work with the higher voltages seen when things like a 3, or single wire alternator brings the run voltages to 14.60 or so. If this occurs, I suggest removing the coil from the car and finding a good parts store that has an off vehicle electrical tester, and run the coil, let it get hot. More than likely, it is in some way compromised, and starting to fail.

If that is the case, the failing coil can take module after module out until the coil is replaced. We see a lot of this, coils beginning to fail, causing "HEI module failures for NO APPARENT REASON". NOTHING fails for no apparent reason, nothing.

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