Ignition Cutting Out

[HBChris]

My `69 has 700 miles on it's rebuilt motor, everything is new from water pump to tailpipe. Several months ago the ignition started cutting out while I'm driving, I could coast and it would restart, but sometimes not. I could drive 30 miles and no problems. Since I had an erratic tach that I had to tap to get it going after starting the car, I suspected a short in the tach so I replaced it. Thirty miles later same problem reappears. If I disconnect the tach wire at the coil I can restart it. So, I replaced the tach wire too as resistance in the wire can cause issues even if not broken.

After 110 miles of no issues over the last two weeks, including drives of 30 miles, it died while driving and would not restart. I disconnect tach wire again and it makes it 10 miles and dies again, and tach is still disconnected. This is the first time it has ever died while tach is disconnected so it ain't the tach!

Coil, wires, plugs, points, condensor, rotor, cap all have less than 1000 miles. Car runs great. Points are tight as is condensor. I am at my wits end, what is it that is obviously heat related that is causing the motor to die?

Chris

[c.d.iesel]

...after all you state above - recheck the points - how they're installed?, flatly ion base?, wire from points touching something it

shouldn't?, DWELL/Point Gap correct?, points pitted?

outside of the distributor- wire again cood condition?,

connections tight and clean? wires to the coil clean and tight?......................

i hope it not something silly

[HBChris]

Thanks c.d.

I checked those items, points, rotor, cap no pits, wires tight including condensor, wire at points snug, no play in base of points. I am going to check dwell and timing this afternoon but it runs great. The coil was new (red or also known as black since I still use ballast resistor). I have heard of new coils being bad that sat too long, is this even possible? I assume the coil 'could' be getting too hot perhaps?

[JohnS]

Chris,

Are you using the correct 1.8 ohm ballast resistor with that red coil? I know that some years of 2002 used a black coil that required a 0.9 ohm resistor. Other black coils (like the ones on my tii) required the 1.8 ohm resistor (it's labelled as such on the coil). The ohms of the resistor should be marked (cast into it's metal base) of the resistor. 1.8 ohm resistors ussually have a metal base that's sort of copper (red) colored. If you're using the proper 1.8 ohm resistor, you should measure about 10 volts at the coil after the resistor when running.

John

[HBChris]

John,

Great thought. The red coil needs 1.9 resistance, on my ohm meter I am seeing 1.0 to 1.1. Bosch number is 1 224 509 063, I will try to look this up. thanks!

Chris

[HBChris]

Well, I just measured 10v at the coil (term 15) and 10v at output of resistor, input to resistor is 13.3v. Unless resistor gets hotter after driving and fails overheating the coil.

[JohnS]

Bosch part #1224509063 is for the 0.9 ohm resistor. You can get the correct 1.8 ohm Bosch resistor from Autohausaz (Bosch #0227901014)

http://www.autohausaz.com/search/product.aspx?sid=gfkiyz451gungn553prtp555&pn=W0133-1627679,

[HBChris]

You may have solved the mystery although I was getting the correct 10V at the coil. When this car was parked in '89 it had the blue coil. My other thought was a bad connection at the resistor relay which I still have connected although really not needed in this climate and with the M3 starter. Did you receive your package today?

Chris

[JohnS]

I hope that it helps. I think that running the wrong resistor can possibly fry your points.

Here's the original coil from my '73 tii. Black KW 12V clearly marked as needing the 1.8 ohm resistor.

On the left is a new style Bosch 1.8 ohm resistor. On the right is the original one from my '73 tii. I had to make up the connectors on the new style resistor so that I could use my original push-on wire connectors.

Another example of a Bosch Super-Coil KW 12V (Red version). This is the one I replaced my original Black one with because I think it looks cooler, but they're the same.

[allbim]

Why not check the voltage at the coil next time the car quits on you?

[AustrianVespaGuy]

If you have access to one, try popping in a blue coil and wire it up directly with no ballast resistor/no resistance wire (that some later cars have). This will tell you whether your problem is with the coil circuit or not. While the blue coils may not be the 'best,' they are the simplest/most straight forward to get a functioning ignition circuit.

-Carl

[Mike Self]

One more "outlier" thing to check....

Pull the dizzy cap and look at the carbon contact button in the center, that allows the rotor to make contact with the cap. It's spring loaded, and if it's stuck or not moving at all (or broken) it can cause the symptoms you describe.

I don't think the tach has anything to do with your ign cutting out, as it's not wired in series with the distributor or coil low tension circuit. It's probably coincidental.

cheers

mike

[Kpeters]

This is very interesting want to see how it turns out as I may need to troubleshoot this in the future. Subscribing...

[HBChris]

Thanks everyone. John, I have the same red coil and will get the proper resistor, I know too much current can damage the points.

Chris

[JohnS]

I'd check out Mike's advise about the carbon pin in the distributor cap too. I've had that problem happen with a brand new distributor cap that was only about a week old. The carbon pin's spring action was sticking. Good luck.