[C2] electrical issues
Thread Starter
Heel & Toe
Joined: May 2013
Posts: 15
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From: Provincetown Massachusetts
electrical issues
Electrical issues driving me nuts...Any help appreciated.Two issues...not sure if they are related...With stock voltage regulator, the dashboard gauge climbs like a tach when revving engine, and I measured almost 19 volts to the battery !....You can smell the battery boil..tried 2 new regulators, and got the same results
2. Dashboard Tach seems to work fine on acceleration up to about 3800 rpm, then as you continue to rev engine, tach fluctuates and drops, even though engine revs continue to rise...Tried 2 independent tachs, including a new Sun tach, and got similar results....Guessing it must be an electrical issue...Engine seems to run fine, but readout at the tach is all over the place...checked ground wires...starter, chassis straps, etc...all grounds appear to be good, including volt regulator and alternator ground....Any ideas?
2. Dashboard Tach seems to work fine on acceleration up to about 3800 rpm, then as you continue to rev engine, tach fluctuates and drops, even though engine revs continue to rise...Tried 2 independent tachs, including a new Sun tach, and got similar results....Guessing it must be an electrical issue...Engine seems to run fine, but readout at the tach is all over the place...checked ground wires...starter, chassis straps, etc...all grounds appear to be good, including volt regulator and alternator ground....Any ideas?
Team Owner
Joined: Jul 2001
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From: Various places in Southern California.
The alternator is putting out full power, which means the field wire is putting full voltage to the alternator. I'd check the wiring at the regulator as well as the wiring between it and the alternator. There may be a short between a hot wire and the field wire, which would put the alternator into full-field mode.
As for the tach, isn't it a cable-driven tach? Are we talking about a mid-year car here?
As for the tach, isn't it a cable-driven tach? Are we talking about a mid-year car here?
Thread Starter
Heel & Toe
Joined: May 2013
Posts: 15
Likes: 0
From: Provincetown Massachusetts
As for the tach, isn't it a cable-driven tach? Are we talking about a mid-year car here?[/QUOTE]
Thanks for the reply..The tach is mechanical drive...sorry about the confusion....the problems I have when connecting an electronic tach are a different issue.....probably related to a coil problem....I am now using a flamethrower III coil with a pertronix ignitor III distributor setup...the mechanical tach seems to climb to just under 4k, then is erratic....I guess it must be the cable or the tach gears
As for the electrical issues, I may try to bypass the stock wiring harness from the alt to volt reg and see if that solves it
Thanks for the reply..The tach is mechanical drive...sorry about the confusion....the problems I have when connecting an electronic tach are a different issue.....probably related to a coil problem....I am now using a flamethrower III coil with a pertronix ignitor III distributor setup...the mechanical tach seems to climb to just under 4k, then is erratic....I guess it must be the cable or the tach gears
As for the electrical issues, I may try to bypass the stock wiring harness from the alt to volt reg and see if that solves it
Team Owner
Joined: Aug 2007
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Army
The Pertronix III has a built-in rev limiter - it is preset at like 4400RPM or the like...you need to read up on that and determine if that is your issue. They are set with a small screwdriver and tiny LED light which you MUST interpret correctly to determine the setting. Its just like Morse code....long flashes/short flashes of a certain number. Whoever installed it might have screwed up the setting.
Check that out. I usually set it at 4800 for base motors and 5800 for SHP engines. Early FlameThrower coils were known to be failure-prone....many run alternatives such as the MSD Blaster-II 8202 (which is what I use). Just peel the label off and paint it black.
As to the voltage issue, the alternator is clearly 'running away'; don't operate the car for more than a few seconds like that. A Dr Rebuild OOSoEz pictorial schematic is the best documentation you'll buy for your car when dealing with wiring and connectors...
Check that out. I usually set it at 4800 for base motors and 5800 for SHP engines. Early FlameThrower coils were known to be failure-prone....many run alternatives such as the MSD Blaster-II 8202 (which is what I use). Just peel the label off and paint it black.
As to the voltage issue, the alternator is clearly 'running away'; don't operate the car for more than a few seconds like that. A Dr Rebuild OOSoEz pictorial schematic is the best documentation you'll buy for your car when dealing with wiring and connectors...
Last edited by Frankie the Fink; Aug 25, 2017 at 07:54 AM.
Le Mans Master
Joined: Dec 2004
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2024 C2 of the Year Finalist - Modified
2023 C2 of the Year Finalist - Modified
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Electrical issues driving me nuts...Any help appreciated.Two issues...not sure if they are related...With stock voltage regulator, the dashboard gauge climbs like a tach when revving engine, and I measured almost 19 volts to the battery !....You can smell the battery boil..tried 2 new regulators, and got the same results
2. Dashboard Tach seems to work fine on acceleration up to about 3800 rpm, then as you continue to rev engine, tach fluctuates and drops, even though engine revs continue to rise...Tried 2 independent tachs, including a new Sun tach, and got similar results....Guessing it must be an electrical issue...Engine seems to run fine, but readout at the tach is all over the place...checked ground wires...starter, chassis straps, etc...all grounds appear to be good, including volt regulator and alternator ground....Any ideas?
2. Dashboard Tach seems to work fine on acceleration up to about 3800 rpm, then as you continue to rev engine, tach fluctuates and drops, even though engine revs continue to rise...Tried 2 independent tachs, including a new Sun tach, and got similar results....Guessing it must be an electrical issue...Engine seems to run fine, but readout at the tach is all over the place...checked ground wires...starter, chassis straps, etc...all grounds appear to be good, including volt regulator and alternator ground....Any ideas?
Last edited by dcamick; Aug 25, 2017 at 08:19 AM.
Le Mans Master
Joined: Dec 2004
Posts: 5,394
Likes: 2,767
From: Pittsburgh
2024 C2 of the Year Finalist - Modified
2023 C2 of the Year Finalist - Modified
2022 C2 of the Year Finalist - Unmodified
2019 C1 of Year Finalist (appearance mods)
The Pertronix III has a built-in rev limiter - it is preset at like 4400RPM or the like...you need to read up on that and determine if that is your issue. They are set with a small screwdriver and tiny LED light which you MUST interpret correctly to determine the setting. Its just like Morse code....long flashes/short flashes of a certain number. Whoever installed it might have screwed up the setting.
Check that out. I usually set it at 4800 for base motors and 5800 for SHP engines. Early FlameThrower coils were known to be failure-prone....many run alternatives such as the MSD Blaster-II 8202 (which is what I use). Just peel the label off and paint it black.
As to the voltage issue, the alternator is clearly 'running away'; don't operate the car for more than a few seconds like that. A Dr Rebuild OOSoEz pictorial schematic is the best documentation you'll buy for your car when dealing with wiring and connectors...
Check that out. I usually set it at 4800 for base motors and 5800 for SHP engines. Early FlameThrower coils were known to be failure-prone....many run alternatives such as the MSD Blaster-II 8202 (which is what I use). Just peel the label off and paint it black.
As to the voltage issue, the alternator is clearly 'running away'; don't operate the car for more than a few seconds like that. A Dr Rebuild OOSoEz pictorial schematic is the best documentation you'll buy for your car when dealing with wiring and connectors...
