Losing Ignition

stewwolfe

stewwolfe

Senior Member
I've got an issue in my Roadster that has me stumped. When I turn on the key I have ignition. When I step on the starter it will fire, but just for a moment, and then I lose spark. I've tried swapping out the coil and it didn't change anything. I then swapped out the condenser, still no change. I bypassed the amp meter, with no success either. I've walked through the wiring and replaced one connector, which seemed to help for a minute (it actually ran for 30 seconds), but it went back to the same situation again (no spark). We are getting 4.5 volts at the positive terminal of the coil while the starter is running. Does anybody have any ideas where to go from here?
 
Prop your points open with a stick or something, key on, put a test light on the movable arm, shake everything, including working the spark lever up and down, and see if the light goes out. It should not go out. If it goes out, find out where the short to ground is and fix it.
 
What Jackson says, but first is your car/ignition stock?

The reason I ask is the other day I spent some time trying help someone and then the guy says BTW this is a resto-rod... WTF? :p:p

So a little back ground please before people start making suggestions. :) Pop out? Stock or modern ignition? etc?
 
I took Jack's suggestion and propped the points open and started shaking things. No such luck! Then I went back to testing the spark by shooting a spark from the coil wire to a head nut. I noticed that as soon as I touched the points (before they had even really opened) I was getting a small spark out of the coil wire. This led me to investigate the points and voila they were pretty badly burned and pitted. A little dressing with a point file and now she starts and runs like a top. FYI I have NOS original points that have about 2,500 miles on them. I feel like a bit of a fool because I didn't follow my own frequent advice to walk through the simple possibilities before diving elbow deep into the issue. Thanks to all for the suggestions!
 
If the points go bad quickly, or spark too much, then the condenser should be replaced. I think most dealers sell the good one made by A&L.
 
Hi there I had a similar problem with my 30 Coupe.
Turned out to be a bad cable for the ignition switch to the dist.
Must have had a break in it somewhere - it was intermittent.
Drove us crazy for awhile.
Good luck ... Chris
 
I would start with a logical path troubleshooting before shotgunning parts.
Use your digital volt/ohm meter and check voltage at the starter switch. Take reference, should be the same voltage at both terminal box studs, then both sides of the coil ignition switch off. Then turn on the ignition switch and with points open ( or insulated whichever you choose) check the voltage at the moveable arm. Should be about the same. If significantly less you have a poor connection either at the ignition switch, pigtail to the distributor, or in the distributor itself. Using the volt ohm meter will help you determine quickly where there is a poor connection. If in the distributor you will have to remove the cam/upper plate, and determine where the problem is.

Keep us posted. If you don't have a meter a test light will help but will NOT show you low voltage which in turn signals you to where the problem may be.

possibly when it quits key still on take the voltage checks as well to see if you can determine where you are losing it.

Larry Shepard
 
Yes, it's fixed. I appreciate all the help, which I knew that I would get when I made the original post. Thank you all!
 
Sometimes when we have trouble, we make a mental "list" of how to ATTACK it.
In the end, we sometimes find that we should have started at the BOTTOM of the "list" & worked UP!
SIMPLE DIAGNOSIS is always the FIRST step!!! When you do this for a living, you won't last long, if you CAN'T DIAGNOSE, quickly & accurately!!! On baffling problems, many times the actual repair is SIMPLE.
Bill Curious
 
Just an FYI.
For this same situation or very similar. Friend of mine called me up saying his 30 coupe just up and stopped running while driving. After a bit of searching around and wiggling things around, found that the screw on his Junction Box loosened a bit and moved just enough to short to the body.
I would recommend that anyone replacing or working the terminals in the Junction Box, take if OFF the firewall, tighten the screws with a dab of nail polish to secure the nut and personally, I filled the back hole with ShoeGoo, or a bit of silicone sealant will do the job too. DO NOT use any Loctite or the same as it could attack the plastic of the Junction Box and destroy it.

My 2¢
 
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