Not getting 12 volts on crank
Thread Starter
Intermediate
Joined: Oct 2015
Posts: 46
Likes: 0
From: Quad Cities Illinois
Not getting 12 volts on crank
Hey guys, I've got another thread here but I'm wondering if this sticks out to anybody. I'm having a hell of a time getting my 73 automatic to strat cold. After a bunch of testing we've run a wire straight from the ign on thr fuse box to a voltmeter to see what it's reading. We get 12.4 in the on position. And it drops to about 8.5ish on crank. What could be causing this?
Emerging Vendor
Joined: Mar 1999
Posts: 1,599
Likes: 114
From: San Diego CA
Thats normal as the resistance wire for the points ignition drops the voltage. Check coil and condition of points.
Does it start ok when warm? Is the carb choke working correctly?
Does it start ok when warm? Is the carb choke working correctly?
Last edited by corvgreg; Sep 10, 2017 at 03:17 PM. Reason: add more info
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
It is NOT normal as he is taking the voltage reading at the IGN terminal at the fuse box which is before the resistance wire. Also, with the key in the START position the resistance wire to the coil is bypassed with the bypass wire from the starter to the coil positive terminal.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
How good is your starter?
Are you sure all connections at the solenoid are tight and correct??
Also do what 'terry82' in post #3 suggested...it is a good thing to verify
Also make sure your battery cable connections at the battery are clean and .
I am not shocked that the voltage drops when you crank the engine..that is normal due to the amount of current that the starter circuit commands when you go and start the engine. Proof is that if you go and try to start your engine with the headlights on..they dim.
I have seen the voltage drop as low a 9.0 volts on some Corvettes.
Without having any more detailed information about your 'cold start' issue. It is pointless to type out numerous variables.
I can say that I have dealt with numerous starters where the armature bearings/bushings were worn along with the brushes and the armature was actually scrubbing slightly against the field coils inside the starter.
A very good description of what the engine is doing when it is cold when you crank it would help...along with any information about the timing and if you know for sure your carb is getting fuel and that the fuel is good fuel.. and so on..they all can be factors.
DUB
Are you sure all connections at the solenoid are tight and correct??
Also do what 'terry82' in post #3 suggested...it is a good thing to verify
Also make sure your battery cable connections at the battery are clean and .
I am not shocked that the voltage drops when you crank the engine..that is normal due to the amount of current that the starter circuit commands when you go and start the engine. Proof is that if you go and try to start your engine with the headlights on..they dim.
I have seen the voltage drop as low a 9.0 volts on some Corvettes.
Without having any more detailed information about your 'cold start' issue. It is pointless to type out numerous variables.
I can say that I have dealt with numerous starters where the armature bearings/bushings were worn along with the brushes and the armature was actually scrubbing slightly against the field coils inside the starter.
A very good description of what the engine is doing when it is cold when you crank it would help...along with any information about the timing and if you know for sure your carb is getting fuel and that the fuel is good fuel.. and so on..they all can be factors.
DUB
