Timing Light Question
Thread Starter
Instructor
Joined: Jul 2002
Posts: 125
Likes: 1
From: Fort Walton Beach Fl
Timing Light Question
It's been a while since I've had my timing light out but I went to use it and no strobe. I did use the battery in the car as the power source and put the clamp around the number 1 spark plug wire and disconnected the vacuum advance. It just so happens that I have another, identical timing light. Hooked it up and nothing until rpm's increase and then strobe starts flashing. Both lights doing the same. This has to be operator error but what am I missing? The motor is a 1970 LT1 with points. Thanks in advance.
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
Maybe a dirty or corroded battery terminal or bad ground? With my dial back I usually use the red positive connector on the back of the alternator and for negative the front brake line nut on the master cylinder. Both are right there.
Edit: Looks like HeadsU.P. can type faster than me....
Edit: Looks like HeadsU.P. can type faster than me....
Last edited by CanadaGrant; Feb 26, 2019 at 07:29 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Maybe a dirty or corroded battery terminal or bad ground? With my dial back I usually use the red positive connector on the back of the alternator and for negative the front brake line nut on the master cylinder. Both are right there.
Edit: Looks like HeadsU.P. can type faster than me....
Edit: Looks like HeadsU.P. can type faster than me....
Race Director
Joined: Oct 2008
Posts: 19,147
Likes: 1,667
From: Long Island
Make sure the Tab on the piece that goes over the plug wire is closed. One of mine will not work unless the tab is closed and touching the base.
Check for corrosion on the battery clips on the timing light cables..
A little "White-out" will make the mark show up better.
Check for corrosion on the battery clips on the timing light cables..
A little "White-out" will make the mark show up better.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,334
From: North of Toronto - Ontario
For what it's worth, hook it to the #3 wire and see if it acts the same, it's possible, although maybe not likely that it's not properly firing #1 at idle
Or, it's also possible the voltage is weak at idle, (alternator output goes up with the RPM)
Just a thought.
M
Or, it's also possible the voltage is weak at idle, (alternator output goes up with the RPM)
Just a thought.
M
Thread Starter
Instructor
Joined: Jul 2002
Posts: 125
Likes: 1
From: Fort Walton Beach Fl
Just went out to try moving the power source to the alternator and an engine ground, still no go. I started moving the clamp, first to #3 and nothing, next to #5 and now it's flashing, The same with #7. Does this sound like it was never set up correctly with #1 at TDC on the compression stroke with the rotor aligned to it? I say this because I know that it has been apart before I owned it. I have not checked charging voltage yet but the battery seems strong.
Last edited by Bigb69; Feb 26, 2019 at 08:05 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,334
From: North of Toronto - Ontario
If it runs, all should flash regardless of where the dist was set or if the balancer is spun or whatever, just won't flash at the timing mark. If the voltage is right (or decent) either those cylinders aren't actually firing at idle (should be rough as hell / flooding) or there's something wrong with the wires/ground.
M
M
Thread Starter
Instructor
Joined: Jul 2002
Posts: 125
Likes: 1
From: Fort Walton Beach Fl
This all began because it is running so rich that your eyes water and you'll choke on the fumes. I assumed it was the carb at fault. I changed plugs, cap, and rotor. It ran smoother but still too rich, that wasn't any better. I checked the float level and tried to adjust with vacuum gauge but everything I did seemed to take me a step backwards. That's why I wanted to verify the timing and then work from there. Sounds like I need to check for a dead cylinder/plug/wire. Hopefully I'm moving in the right direction??
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,334
From: North of Toronto - Ontario
Always start with timing 
Check #2 wire with your light, if it's OK, swap the wire with #1 wire (should be long enough to trade those two) and see if it's good on #1, if it's good on #1 then the wires are a problem, if it's still dead on #1, check the plug or cap / rotor (just cause it's new doesn't mean it's not faulty) or put your old cap back on and re-test
M
Check #2 wire with your light, if it's OK, swap the wire with #1 wire (should be long enough to trade those two) and see if it's good on #1, if it's good on #1 then the wires are a problem, if it's still dead on #1, check the plug or cap / rotor (just cause it's new doesn't mean it's not faulty) or put your old cap back on and re-test
M
Last edited by Mooser; Feb 26, 2019 at 08:51 PM.
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
Just went out to try moving the power source to the alternator and an engine ground, still no go. I started moving the clamp, first to #3 and nothing, next to #5 and now it's flashing, The same with #7. Does this sound like it was never set up correctly with #1 at TDC on the compression stroke with the rotor aligned to it? I say this because I know that it has been apart before I owned it. I have not checked charging voltage yet but the battery seems strong.
Last edited by CanadaGrant; Feb 26, 2019 at 10:48 PM.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,334
From: North of Toronto - Ontario
Intermediate
Joined: Sep 2018
Posts: 40
Likes: 12
From: Huntingtown, MD
You might also want to check your ignition coil? Easy enough to check out of you have a digital meter. If interested you can find good info with instructions of how to do it here.
http://www.secondchancegarage.com/pu...leshooting.cfm
The reason I suggest the coil is.....? What are the chances a few of your plug wires going bad at the same time without a good reason? The common denominator is the ignition coil. If the coil is weak? The spark will also be weak. I could be wrong? But, there may not be enough spark traveling through the wire on number 1, or several of the other wires you have switched your timing light to in order to trigger your timing light?
Just a thought?
Good Luck,
White One
http://www.secondchancegarage.com/pu...leshooting.cfm
The reason I suggest the coil is.....? What are the chances a few of your plug wires going bad at the same time without a good reason? The common denominator is the ignition coil. If the coil is weak? The spark will also be weak. I could be wrong? But, there may not be enough spark traveling through the wire on number 1, or several of the other wires you have switched your timing light to in order to trigger your timing light?
Just a thought?
Good Luck,
White One
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
also, the metal "jaws" of the "core" inside the clip ... they can become slightly loose ... and, if they do Not contact one-another when closed around wire ... it won't trigger.
My light is ~ 42 years old SUN induction (Not dial-back) with the rubber, screw-on snout housing a glass optic ... its last strobe bulb replacement came off the shelf at a local, Loooooong closed Radio Shack. Put a baggie over the snout with a rubber band when I tuned harleys; never liked plastic timing mark case plugs.
Dr. Detroit
Joined: Mar 2012
Posts: 10,095
Likes: 4,022
From: New Braunfels Texas
Do both timing lights work well on another car? If so then put a hot battery on a cart and use it to power the light. If you still have issues then either the inductive pickup or a bad wire.
I have never had a problem using an ancient Craftsman strobe with Taylor wires.
Let us know what you find.
Jebby
I have never had a problem using an ancient Craftsman strobe with Taylor wires.
Let us know what you find.
Jebby
Race Director
Joined: May 2006
Posts: 18,665
Likes: 2,564
do you have an ohm meter? if so measure the resistance of each plug wire, it should not measure more than 1,000 ohms per foot of wire. If the wires are old carbon core wires it is quite possible for more than one to be bad.
Last edited by MelWff; Feb 27, 2019 at 11:34 AM.