Testing ECU on BBi

Does anyone know how to test the ignition ECU on the Boxer? I put my timing light pick-up on the coil wire, and get flashes, with intermittent breaks.

 

On a BB, the No 1 lead is so long it's very common for a timing light to get a weak signal. I time using the No 6 lead and get better results.

Does your intermittant flash coincide with a misfire? If not, I'd not worry. If you have a misfire, and listen carefully on a BB as they're so smooth it's hard to pick up one cylinder, then you need to put it on a scope to observe the spark traces. Anything over 28kv is too high and you have a problem with anything from a plug/gap to a lead or extension or inside the cap........

 

Phil: The intermittent flashing comes with corresponding misfiring. I have replaced all plugs. My spark tester is showing around 6KV on all wires 1-12.

While trying to time it, with plug #1, I can't seem to get the flywheel steady enough for a good reading.......it fluctuates back and forth quite a bit.

I put my timing light pick-up on the coil wire, so that I can observe the flashes, BEFORE they enter the distributor........that way I can rule out the cap and rotor as problem areas.

When you time with #6, what marks on the flywheel are you using?

 

You use the same mark....it's PM 1-6 so it's exactly the same as using No1.

If you have a lot of variation........it's one of the most common Boxer problems, to have sticky bob weights in the distributor.

Remove the dizzy and do an overhaul of the internals. You may be lucky to just do a full strip and rebuild with new lubrication, but you may need new parts. Be careful with the small wires and screws on the Hall effect sensor when removing it.

To lubricate the inside, I use motorcycle or chainsaw lube spray. It doesn't fling off so easily and you only put enough on to do the job without having great big globs of greasy goo everywhere.

Be sure to set up the static timing before removal.

Hey, I just realised this is post number 512 for me!!

 

Thanks Phil: I took the distrib off, and will take it apart. Is it possible that the pick-up coil is bad?........any way to test it?

Thanks again.

 

The pick up coil, or Hall effect sensor is magnetic. If it's still strong you will see that the distributor will stay in a position that aligns the arm. You can spin it like "wheel of fortune" and it will stop dead on a signal position.

You can test the windings for continutity but I don't have a figure for a resistance value off hand.