Low volts at starter
Thread Starter
Intermediate
Joined: Jun 2014
Posts: 41
Likes: 1
Low volts at starter
Hi all,
Have a 68 manual that has an intermittent starting problem.
Have discovered that when it won't start have low voltage on the starter.
Not heat related, just an intermittent electrical problem that only seems to occur when am not at home.
Checked all the grounds and cleaned them up.
Been working my way back down the purple wire and reached the fire wall.
Before I start heading inside the cab was wondering if anyone has pointers as to likely culprits?
From the wiring diagram looks like, either the connector through the firewall or key barrel.
Appreciate any thoughts
Have a 68 manual that has an intermittent starting problem.
Have discovered that when it won't start have low voltage on the starter.
Not heat related, just an intermittent electrical problem that only seems to occur when am not at home.
Checked all the grounds and cleaned them up.
Been working my way back down the purple wire and reached the fire wall.
Before I start heading inside the cab was wondering if anyone has pointers as to likely culprits?
From the wiring diagram looks like, either the connector through the firewall or key barrel.
Appreciate any thoughts
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Low voltage on the big cable at the starter?
Thats going to be a bad battery cable connection, corrosion in the lug, that sort of thing.
Remember, the voltage is sourced from the battery, follow it out from there. If your good at the battery terminal, then go to the battery cable connector at the battery, then to the starter and so on.
Thats going to be a bad battery cable connection, corrosion in the lug, that sort of thing.
Remember, the voltage is sourced from the battery, follow it out from there. If your good at the battery terminal, then go to the battery cable connector at the battery, then to the starter and so on.
Thread Starter
Intermediate
Joined: Jun 2014
Posts: 41
Likes: 1
Low voltage on the big cable at the starter?
Thats going to be a bad battery cable connection, corrosion in the lug, that sort of thing.
Remember, the voltage is sourced from the battery, follow it out from there. If your good at the battery terminal, then go to the battery cable connector at the battery, then to the starter and so on.
Thats going to be a bad battery cable connection, corrosion in the lug, that sort of thing.
Remember, the voltage is sourced from the battery, follow it out from there. If your good at the battery terminal, then go to the battery cable connector at the battery, then to the starter and so on.
The voltage on the big lug is ok, checked all the obvious battery connections etc. have pulled, cleaned all the terminals and grounds.
The low volts is on the s-terminal, the purple wire starter signal wire.
The starter fires up just fine when I jump the s terminal directly to the big lug giving it full 12 volts. So my issue is definitely on the starter signal wire. I know it will be a bad connection and from the look of it, it is inside the cab. Really don't want to attack the dash again, am a bit over pulling it apart, which is why I though I would ask if any knows of a likely culprit.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I bet you have a ignition interlock switch is bad or wiring/plug/interconnect is bad or out of adjustment on the linkage.....it's there so you can't move the car with the trans in gear.....
ME, I"d just find the purple wires and get rid of that .gov regulation and use common sense.....
ME, I"d just find the purple wires and get rid of that .gov regulation and use common sense.....
Burning Brakes
Joined: Aug 2004
Posts: 802
Likes: 1
On my 73 manual, the shifter switch located on the tranny linkage under the car only drives the back up lights and nothing else.
The purple wire from the starter goes directly to the switch on the clutch pedal under the dash. Then from there it goes directly to the ignition switch mounted halfway down on the steering column where the key is used to move the switch into the start position.
I would check the clutch switch first, it may be out of adjustment when being activated by the clutch pedal. You could jumper the connector at the switch to de-activate it completely for testing purposes only.
But it is a bugger to get to.
Steve L
73 coupe since new
The purple wire from the starter goes directly to the switch on the clutch pedal under the dash. Then from there it goes directly to the ignition switch mounted halfway down on the steering column where the key is used to move the switch into the start position.
I would check the clutch switch first, it may be out of adjustment when being activated by the clutch pedal. You could jumper the connector at the switch to de-activate it completely for testing purposes only.
But it is a bugger to get to.Steve L
73 coupe since new
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,599
Likes: 7,046
From: New Or-leens Loo-z-anna
I had the same problem on my '68.
The previous owner installed an HEI distributor but he did not run a new wire from the fuse box to the HEI terminal (He continued using the resistor wire that connected to the old points type distributor.
As for the purple wire....this is the easiest way to find a bad section of wire...take a multimeter....turn the ignition switch on.....probe the purple wire along the firwall every two feet to see where the voltage changes-----
if there is no voltage change, then test the purple wire from the fusebox along behind the dash until you find a voltage change.
I found 3 bad repairs in the purple wire/a corroded terminal in the fuse box/a neutral safety switch out of adjustment.
The previous owner installed an HEI distributor but he did not run a new wire from the fuse box to the HEI terminal (He continued using the resistor wire that connected to the old points type distributor.
As for the purple wire....this is the easiest way to find a bad section of wire...take a multimeter....turn the ignition switch on.....probe the purple wire along the firwall every two feet to see where the voltage changes-----
if there is no voltage change, then test the purple wire from the fusebox along behind the dash until you find a voltage change.
I found 3 bad repairs in the purple wire/a corroded terminal in the fuse box/a neutral safety switch out of adjustment.
Thread Starter
Intermediate
Joined: Jun 2014
Posts: 41
Likes: 1
Thanks all,
Ran out of time to check everything, nothing too major yet.
I promised the vette for a friends graduation this weekend, so I wired up a relay that is triggered off the purple wire that puts a full 12 v on the starter. Not my preferred solution but at least she should start.
Will do a deeper dig on the above in a couple of weekends, has the clutch and neutral disconnected already. Didn't get to the bottom of how they bypassed them, could be a problem if wires are just twisted together.
Door gunner, thanks for the thought on the HEI mine also has a HEI installed, so will be tracing that wire as well.
Glenn
Ran out of time to check everything, nothing too major yet.
I promised the vette for a friends graduation this weekend, so I wired up a relay that is triggered off the purple wire that puts a full 12 v on the starter. Not my preferred solution but at least she should start.
Will do a deeper dig on the above in a couple of weekends, has the clutch and neutral disconnected already. Didn't get to the bottom of how they bypassed them, could be a problem if wires are just twisted together.
Door gunner, thanks for the thought on the HEI mine also has a HEI installed, so will be tracing that wire as well.
Glenn
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Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
What voltage are you reading that you consider low? The value could help figure out what is causing it to be low.
Good luck... GUSTO