New wiring - new battery...won't start

[Jim Gaspard]

After several hours in Search Mode, I am resorting to asking for some advice on the Forum. Several weeks ago I finally decided to replace my original frayed wiring on my B3B Driver with a new set from Rhode Island Wiring I ordered 2 years ago for my Frame-Off. I was getting some battery drain in between starts. I made the final wiring hookup Friday night and installed a new Optima 6 V battery with new 0 Gauge battery cables. Started ok before the project. Won't start now.

I am trying to solve by deductive elimination. Back tracked the hookups, everything checks. Replaced the V Regulator with a new one. Installed new plugs. Replaced distributor cam and rotor. I did tape one of the sparkplugs where I could see it through the window when cranking and it does NOT appear to have a spark. I guess this leaves either the coil is bad or the condenser/points are not gapped correctly, or ????. Before I disconnect the distributor for overhaul, does anyone have some advice of what I might have overlooked.

If there's a string on this in Technical section just give me the location. I can't find anything specific. Is there a way to test the coil to see if its bad? Thanks.

[Don Coatney]

Jim;

My day job in part includes re-wiring over 100 circuits in a machine. I have done this job over 40 times in the past 3-4 years. But I still make mistakes. When I do I start on the circuit that is not working and do a wire to wire search using an ohm meter as required to find the problem. Nobody here can tell you what is wrong. You need to do a wire to wire search on your vehicle to find the problem. If it ran before you started your re-wire project then something is not correct with your re-wire.

[JBNeal]

Yep, looking at each wire connection is required, starting with the power source. My guess is that the coil is not being energized, possibly from a ignition switch failure or a coil failure, maybe even the amp gauge isn't working properly. Has the new voltage regulator been polarized? I can't remember if that would affect the ignition circuit.

[Plymouthy Adams]

each system in the harness as Don says is individual..they just taped together and makes it look like a monster...you do not need to have the engine turning to correct verify the ignition circuit..you need just to have the key on and the battery hooked up..you can pull the coild wire out the distributor cap and with the cap off and looking in at the points..first if they are open..short across them with a screwdriver..this will engerized the coil and when you remove the screwdriver the field will collaspe and give you that secondary voltage through the coil wire..if the points are closed already..you just need to open them to get the same result..thi is step one..verifying you have ignition..let us know if it passes this test..if not them be sure to check for voltage to the coil and ensure that the other side is going to ground through the points..could be this wire is shorted prior to the points..

[rustyzman]

Fastest way to begin is with a couple of basic checks. First, I assume that it cranks over, but does not start. With the key on you need to check for voltage at the ignition coil. Even a test light is ok for a quick check here (or a 6v light bulb connected to ground on one leg). If you have voltage here, next connect your test light between ground and the terminal for the points on the distributor. Crank the engine and watch the light. If all is well in the points circuit, you will see the light pulsate or flash when the points open and close (this can be a bit subjective if the engine is cranking slowly and the battery voltage is raising and lowering a bit with the load). If you have proper feed and proper point control, then go look and see if you have spark out of the coil itself. If yes, then go to the end of the coil high tension lead and check again. If yes again, and there is no spark at the plugs then the problem is in the cap/rotor or the remaining ignition wires. If no spark is present at the coil and proper feed and point control is present, the coil has failed. If there is no flash when checking at the distributor points terminal, then check out the points and condenser for condition and adjustment. Be sure you do not have a fuel issue. A shot of carb spray down the carb and some cranking will tell you that.

If there is no voltage at the coil at all, then the problem is in your feed wiring and you just need to trace it from there. The good news is there are not a ton of wires on these vehicles so tracing the fault should not be too hard. A test light or an old 6v headlight as a tracing tool is your friend.

This may be too simplistic for you and you may have done all this already, but maybe it will help.

Good Luck,

Pete.

[Fernando Mendes]

1)Starter cranks engine with normal speed.....2)engine does not start....3)Disconnect spark plug cable and hold 1/8" from engine,while starter cranks engine....4)Now we can obtain 3 situations(no spark,Weak spark,Good spark)....a)No SPARK....check all primary(first) and secondary circuit(LOOK OUT FOR CONDENSER) Jim do this first and tomorrow we will see the NEXT sequence.

[Dave72dt]

I like to start at the battery side of the coil for testing ign problems. It's the easiest, most accessable part of the circuit and will point you in the direction you need to go. Power at the batt side of coil tells you problem is in the coil or dist. No power means you need to go towards the battery tracing the circuitry until you find a point that does have power, things like switches, resistors, termminals, broken wires, incorrect wiring. Switches that have had terminals disturbed from wire replacement may no longer work. Tell us where you have power and where you don't and we'll go from there. Check the polarity of the coil also, easy to get it backwards when rewiring.

[dbcooper292]

Hey I like that screwdriver/points hand timing! That's a neat trick. I'm all the time turning it over with the starter. Hunh! Never too old to learn.

DB

[Fernando Mendes]

Hunh! Never too old to learn.

I like more this thinking.Guys I was yesterday looking my WWII GMC CCKW 353 6x6 2 1/2 ton 1944 sequence(TM10-1563) from november'15 1942,it has all for helps a good driver.Of course,we never have all in our mind,like says this thinking above.Only to say for you,I solved a big ignition fault in my Jeep Willys 1/4 ton 4x4 1942 engine two years ago,looking all the sequence wrote in this GMC manual for find the problem.I am liking more of this manual.If JIM wants that I continue the sequence I will wrote all of it.I dont know if you understood my english,ok?

[Jim Gaspard]

Thanks everyone. I'm back from a business trip all week on western slopes of Colorado. I ordered a new coil, condenser, points, rotor and cap from Bernbaum before I left monday morning and it was waiting at my door when I returned last night. I plan on tackling this over the long holiday weekend now that I'm mentally recharged. First to drain winter gas and start fresh, then performing power sequence checks. I'll keep you posted on my progress.

[pflaming]

Jim, I just put my engine back in the frame. Here is what I am going to do: (1) Going to restart it with the hot wire set up to see if something changed when I moved it. I can remove that engine in 45 minute now. (2) when all is confirmed, then (2) will connect to the amp gauge from the battery and from the amp gauge to the toggle switch which I will temporarily mount in the dash. (3) from the toggle switch back to the coil. Now all I have added is the amp gauge. Will restart the engine again.

I will not hook up any other wires until I have my engine running. When completed I will add a wire at a time until all works. Will report back, going to take a bit of a nap now then go restart my engine!!!

Good luck.

Picture: I put a short 2x6 between the fan and the radiator then tied it tightly to the engine and installed the engine, tranny, and the radiator all together. Did it alone in an hour.

Edited November 19, 2017 by pflaming
Added pic and comment