Starting problem diagnostic idea logic check needed
Thread Starter
Racer
Joined: Mar 2008
Posts: 434
Likes: 0
From: Triangle Area NC
Starting problem diagnostic idea logic check needed
My 74 won't turn over...solenoid clunks, but it wont turn over. I've cleaned cables at both end, and charged the battery (I think) with no change.
In order to eliminate cables and battery as the problem, I was going to put a spare battery (top post) on the ground, and run a cable from the positive term to the starter lug (after disconnecting the existing battery of course) and a jumper cable from negative to chassis ground.
If it still doesn't start, I'm fairly sure that the starter is bad. If it does, either the existing battery or the cables (or chassis ground from the battery) is bad, correct?
Also, where does the negative battery cable ground to the engine/chassis?
Thanks for your feedback
John
In order to eliminate cables and battery as the problem, I was going to put a spare battery (top post) on the ground, and run a cable from the positive term to the starter lug (after disconnecting the existing battery of course) and a jumper cable from negative to chassis ground.
If it still doesn't start, I'm fairly sure that the starter is bad. If it does, either the existing battery or the cables (or chassis ground from the battery) is bad, correct?
Also, where does the negative battery cable ground to the engine/chassis?
Thanks for your feedback
John
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
That should work. the main grounds are from the - of the batt to the frame on the drivers side, right below the batt, outside, and from the engine block to a motor mount frame bolt, i believe, on the pass side, rear part of engine. you can use 2 replacement blk batt cables with 2 flat ends with holes, avail at any parts store, in different lengths, if your not too NCRS. 
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
When the starter clunkes = Bendix pulling in to engage the flywheel,
inside the OEM starter Solinoid is a copper disk about 2" Dia. that is supposed to make the contact to allow 12v to the starter motor, after many starts these basicaly get arced and build up resistance, which is what turns the actual starter motor, or Not .... after many years.
Thus smacking the starter sometimes will make the contact good enough to start. you can actually remove the soliniod, dissassemble it, flip the copper washer over, clean up the copper lugs, and you have a new starter solenoid.
The starter solinoid is the final switch that tells the starter to rotate.
After the Bendix has fully engaged the flywheel. (The Clunk )
The negative battery cable goes to the frame, you must also have another negative/GND. cable
going from the frame to the Engine/starter. I assume you have verifiied these cables are solid with NO corrosion.
It the battery were the problem it would crank slowly, ....no Crank at all = Bad solenoid.
69VETT
inside the OEM starter Solinoid is a copper disk about 2" Dia. that is supposed to make the contact to allow 12v to the starter motor, after many starts these basicaly get arced and build up resistance, which is what turns the actual starter motor, or Not .... after many years.
Thus smacking the starter sometimes will make the contact good enough to start. you can actually remove the soliniod, dissassemble it, flip the copper washer over, clean up the copper lugs, and you have a new starter solenoid.
The starter solinoid is the final switch that tells the starter to rotate.
After the Bendix has fully engaged the flywheel. (The Clunk )
The negative battery cable goes to the frame, you must also have another negative/GND. cable
going from the frame to the Engine/starter. I assume you have verifiied these cables are solid with NO corrosion.
It the battery were the problem it would crank slowly, ....no Crank at all = Bad solenoid.
69VETT
Last edited by 69Vett; Oct 4, 2009 at 07:32 AM.
