Intermittent spark when engine cold

[Brent Mills]

I have been having trouble starting my car when the engine has been sitting idle for more than 4+ hours. Over the last several weeks, when it eventually fires after several minutes of turning her over, it'll run just fine and then restart just fine after warm.

Today I was unable to get it started and checked the spark (I had thought it was my 4 48IDA Weber carberetors that were fouling my plugs or something. I've check and rechecked connections. I did the ignition test where I took a paper clip to the wires that lead into the distributor and the spark plug I installed at the end of the coil wire fired perfectly, so it seems the ignition box and the coil are fine?.?.?

When just turning it over with a spark plug in one of the 8 plug wires grounded against the frame, there's no spark at all. What is next?

Thanks for any help.

[Barnsnake]

What's different between the test and actual cranking:

1. When cranking you get a voltage drop due to the starter load, so a marginal battery or high-resistance connections are a possibility. You might want to check the voltage at the ignition box while cold cranking.

2. The spark plug in the coil wire bypasses the distributor cap and rotor. Give them a good inspection, especially the rotor-to-cap contact.

3. The paper clip test bypasses the pickup in the distributor. Given that is one of the most frequent points of failure in an MSD system an inpection and (cold) resistance test is probably warranted.

[Brent Mills]

Thanks Jim. I think I'm going to go and get a new pickup tomorrow and install that.

[Gaz64]

Spark at the coil lead, but not at the plug wires?

Your first test confirms all of the electrics of the ignition, the spark leaving the coil lead is not getting out of the cap.

I'd be looking at rotor and cap.

[lovehamr]

Gary has a good point; is it an MSD cap and rotor?

[FWB]

i would look at the caps center button.......i can't get more than 3500 miles out of a msd cap