Ignition Problem on Sunk A4

[GorgeSantana]

I’m resurrecting an A4 that was sunk and am a bit stymied. I went through Don’s sunk engine checklist and she started on the first try, idled smoothly and took throttle well. I got her up to temperature and shut her off to change the oil (again) and work on other stuff.

After the oil change, she ran for about a minute then she cut off. Eventually I found there was water in the bottom of the distributor, below the plate that holds the electronic ignition unit. I think it splashed up and interrupted the ignition circuit. I dried out the distributor and its cap, but she’s still not starting.

I went ahead and got a new battery. It’s charging now, but I it held 12.25 volts when I used it so I don’t think it’s a problem.

I’ve been focusing on the coil and electronic ignition system. I jumped the positive coil lead straight to the battery but I couldn’t get a spark from either a grounded plug or from the center coil lead to an engine ground.

I rigged up another test to isolate the coil. I removed it from the engine, connected the negative primary to the battery negative terminal and intermittently touched the coil’s positive primary to the battery positive while holding the coil’s output center lead near the engine block. I could only get a miniscule spark to jump. I expected a longer spark so I think this shows a weak coil. Is that a good diagnosis? Is there any way to test the electronic ignition system?

Thanks for your help. What a great forum!

[Don Moyer]

George,

Your test of the coil was basically valid, but you may be expecting too strong of a secondary discharge. Remember that the strength of the secondary discharge is directly proportional to the speed with which you can open the primary circuit each time after you close it. If you allow a lot of arcing as you disconnect the positive lead to the coil, the secondary discharge can become quite weak. For example, simply removing the condenser from the circuit in a conventional system will greatly reduce the secondary discharge.

Don

[Marian Claire]

When she shut down was it sudden or slow? Do you have an electric fuel pump and low oil pressure cut-off? The running for a minute then stopping makes me think of fuel supply. Just some ideas. Dan S/V Marian Claire
Edit: Well done on saving the A-4!

[GorgeSantana]

Humming Along

I couldn't get the Ignitor module to "open" when I hand cranked the engine so it looked to be dead. After I installed a new one she fired right up! She's running better than before she went for the swim. I'm feeling better about this episode....

We've added a larger electric heater, automatic bilge pumps and closed all of the through-hull connectors. I think any one of these would have avoided the sinking.

[Bob Grenier]

Save um one at a time.

It's a job well done anytime we can save one more A4. Now I think this guy may need some help getting this one started. What do ya think?