Now that it is getting dark earlier I have been using the headlights. After about 10-15 mins all the warning lights on the Dash light up and I get sound out of the dash that sounds like 2 wood blocks being hit together.

Occasionally they will turn off, other times they will turn off and come back on.

I suspect this is a grounding issue but I haven't a clue where to start looking.

thanks

Mike b

 

I think you have reduced alternator output. Sounds like it can't keep up with the demand imposed by the headlights, and eventually the battery can't support them either.

Drive with a volt meter, and check the voltage at the battery when you get the lights.

 

This is good analysis! I will do just that. I have a voltmeter handy. I assume the when the xmas tree lights up I will have something less than 12v at the battery terminals?

Also, should I check any belts?

 

Well yeah, definitely check your belt tension.

A fully charged battery should show about 12.5V. If the engine's running you should see around 13.5V. If you have less than that at warm idle rev the engine and observe the resulting voltage.

 

I finally had a chance to measure the voltage across the battery terminal while at idle and I get 13.36v so I'm flummoxed as to why I get the xmas tree effect. Are there any fuses I should check/replace?

 

Search under "Christmas tree effect". There are many things that can cause this, including bad grounds.
In my case, replacing my original coils, solved the problem for me.

 

Well here is a new twist to the story:

I am about to send my distributor out to Mark Cohen for belt replacement. For kicks, I wanted to see what would happen if I remove the coil wire from each distributor and start the car.

When I removed the coil plug from the primary disty cap the entire post came out with the wire! It is the center piece that the plug conductor makes contact with. It doesn't look like it is cracked or broken. It also looks like the post is held in there with simple pressure. These are news caps too from exactly one year ago when I did my valve adjustment/plugs/disty caps.

Could this be the source of the issue and do I need to buy a new Cap? I am also going to replace the plug wires while the distributor is out of the car.

 

You need to load the system- fans on, headlamps on (bright), other electrical equipment on, and maybe the engine should be thoroughly warm.

I dunno about your distributor cap; I'd guess it broke when you tried to take it apart.

 

had something simular it was the head light switch........

 

If the connector in the cap is loose, you will get arcing because of the poor contact. The arcing is usually what causes the Christmas Tree effect.

... Gregg

 

Thanks for all the input guys. I just learned that all the metal posts in the distributor caps that connect to the plug wires are removable/replaceable. Almost all of these posts in both disty caps came out with the plug wires. Fortunately they are easy to push back in.

I am sending the distributor out Mark Cohen for belt replacement. In the meantime I am working up the motivation to replace all the plug wires. When I did the valve adjustment last October I noticed that some of the wires going into the lower passenger side of the engine were saturated with motor oil and looked rotted. My amateur theory is that the electric flow is compromised and causing arcing/grounding problems.

I'm not sure how this is related to headlights causing the Christmas tree on the dash but the wires need changing.

Any other thoughts are appreciated!