73 2.0 Has Issues, Ran GREAT and then it didn't Options

[Minerva's 914]

1973 914 2.0 restored and motor rebuilt by Fat Performance and installed by Black Forest Racing. We've driven her off and on for about 750 over the past year with no problems, in fact she ran fantastic .... until she didn't. Driving around the neighborhood last week the engine bucked a few times with the tach dropping to zero before bouncing back to normal, downshifted and it seemed better only to return again while cruising along at 2800 RPM, down shifted again and since we were only a block away from home made it with no drama. Was thinking maybe an electrical issue shorting out the ignition.

I started the car yesterday evening and backed out of the garage and it stopped dead in her tracks. Turned the key to 0 then back on again and no fuel pump buzz. Proceeded to engage the starter and after several seconds of cranking I returned the switch off, then back on again. No fuel pump buzz.

Checked the relay in the circuit board, switching out the relays, no change. Checked the fuses and connections seem clean so I jumped directly from the battery to pin 12 on the circuit board, turn the key to 1 and got the fuel pump buzz, turned off and back on again got the fuel pump to work.

What do you guys think should be my next step? I planning to get on it early tomorrow and start chasing the wiring but hope someone here might help me narrow down the possibilities. Plan to remove the circuit board, turn it over and check the connections and double check the grounds and then check continuity from the brain, then work my way to the inside fuse panel and wherever else the electrons are circulated before reaching the fuel pump.

As always THANK you guys for all you do to help the 914 live on!!!

Brady

[Dave_Darling]

If the tach drops to 0 even though the engine is still spinning over (even though it isn't firing) then your ignition system has a problem. Could be the power to it, could be the switching part, but something in there has a problem.

If your "tach goes to 0" didn't mean what I said, above, then it's much less of a clue.

Still, not a bad idea to verify that your'e getting spark when the engine won't run.

--DD

[JamesM]

If the tach drops to 0 even though the engine is still spinning over (even though it isn't firing) then your ignition system has a problem. Could be the power to it, could be the switching part, but something in there has a problem.

If your "tach goes to 0" didn't mean what I said, above, then it's much less of a clue.

Still, not a bad idea to verify that your'e getting spark when the engine won't run.

--DD

This is exactly what I was thinking, if the tach pegged to 0 when the engine lost power the problem isnt going to be with your fuel delivery. Signal wire for the tach attaches directly to your coil. Start at the ignition system and work back from there. Are you getting spark?