STILL will not start...utterly lost
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
STILL will not start...utterly lost
Just replaced the Mallory Unilite module but maybe that wasn't the problem. Re-installed distributor and re-wired cap with engine at 8 deg before TDC compression stroke. So the plug firing order is fine.
Ok.
On a fully charged battery and the ignition key in the "ON" position I read approximately 6 volts on the positive terminal of the ignition coil.
While cranking, the voltage drops to even LESS!
I'm using the Mallory coil that does not require a ballast resistor, 29219, so I should see 12v while cranking, right?
I mean when I crank one of the wires from the harness delivers 12v from the starter solenoid, right?
Please tell me what I am missing.
I am totally lost. This is my third trip up to my parent's from San Diego and this is getting old.
I appreciate any and all help.
-Brad
Ok.
On a fully charged battery and the ignition key in the "ON" position I read approximately 6 volts on the positive terminal of the ignition coil.
While cranking, the voltage drops to even LESS!
I'm using the Mallory coil that does not require a ballast resistor, 29219, so I should see 12v while cranking, right?
I mean when I crank one of the wires from the harness delivers 12v from the starter solenoid, right?
Please tell me what I am missing.
I am totally lost. This is my third trip up to my parent's from San Diego and this is getting old.
I appreciate any and all help.
-Brad
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
So when the key is turned to start, the starter cranks the engine but I don't think I'm getting sufficient voltage to the coil.
While cranking the positive terminal on the coil should show 12v, right?
Any ideas?
While cranking the positive terminal on the coil should show 12v, right?
Any ideas?
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
lets hot wire it.....take a jumper from your alternator + post to the battery side of the coil and see what happens. this will give you 12 volts and we can see if that eliminates the problem
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
i always try to eliminate things by hot wiring or using substitue wires.....then when it works you know exactly where to start nosing around....it also makes the entire process a little less frustrating becasue you have narrowed it down to a manageable size>
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Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
thats a pretty big voltage drop.....let make sure all connections for battery to ground, ground from frame horn to engine and battery positive connections are all clean grease free and touching shiny metal...
is your battery charged and do you know if its good?
i would think that you have some basic connections problems and\or perhaps a weak battery.
have you tried jumping your battery with another car and see if this makes any difference on your voltage drop?
edit....lets bring the jumper directly from the battery to the coil wire this will by pass all other electrical systems....disconnect the original wire when you do this
is your battery charged and do you know if its good?
i would think that you have some basic connections problems and\or perhaps a weak battery.
have you tried jumping your battery with another car and see if this makes any difference on your voltage drop?
edit....lets bring the jumper directly from the battery to the coil wire this will by pass all other electrical systems....disconnect the original wire when you do this
Last edited by bobs77vet; Jul 2, 2011 at 09:53 PM.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
poor connections mean increased resistance....increased resistance means big voltage drops....just like you have.....clean all of your battery connections ....not just the posts but the connections on the frame and frame to engine and on starter....
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
i wonder how fast is this thing cranking? with voltage that low are you even spinning the starter fast enough to get the compression you need? does it sound labored when you are cranking it?
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
Just thinking out loud here...but have you checked if you have any spark at the plugs? Pull any one plug wire, insert a spare spark plug and hold the outer case to bare ground on the engine. Crank over the engine. Can you see the plug sparking? What color spark? If yellow, that's weak. Now hold to a good ground somewhere off the engine. Any difference?
Racer
Joined: Apr 2006
Posts: 322
Likes: 0
From: Rockford MI
Just thinking out loud here...but have you checked if you have any spark at the plugs? Pull any one plug wire, insert a spare spark plug and hold the outer case to bare ground on the engine. Crank over the engine. Can you see the plug sparking? What color spark? If yellow, that's weak. Now hold to a good ground somewhere off the engine. Any difference?
Agreed, Do you have spark at the plugs? If so yellow or blue? Yellow indicates a weak spark.
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Thanks for all the ideas. Wasn't able to troubleshoot today but will tomorrow.
I'll test for a spark, and then use my multimeter to check for voltage drop in my battery cables, terminals, starter, etc.
I'll test for a spark, and then use my multimeter to check for voltage drop in my battery cables, terminals, starter, etc.
