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

[Minerva's 914]

Okay, so after a long delay involving travel, photography projects, holidays, flu and snow / cold weather. I finally got back on this project. If you'd care to know the whole background of this mystery jump back to the beginning and follow the various symptoms, suggestions, and fixes tried.

I had proofed the fuel pump by running a jump straight from the battery to fuel pump relay pin 85 on the circuit board, the fuel pump ran continuously, which to me proved to me a) the fuel pump was functioning properly and b) the circuit from pin 85 to the pump was good. I switched out a borrowed ECU and no change as the problem remained. I checked all of the power wiring and power circuit board continuity and all were fine. I removed the steering wheel and found the starter switch had a brown spot indicating it had gotten hot at some point so I replaced it with a new one thinking for sure that was the problem. No change but at least I know have avoided a future problem.

That's where I stopped back in September.

After thinking about it over the winter months I realized I was only thinking about power supply. So I started to check ground. Checking the obvious ground connections with the wiring I then moved to the circuit board. I checked the 14 pin connector to the relay board, pin 10 (ground) to the fuel pump power replay pin 86 by checking the continuity of pin 86 to ground. It failed, no continuity.meaning a bad circuit board!

I located a source for rebuilt circuit board "High Performance House" in Redwood City, CA, installed it yesterday and........

IT'S ALIVE!!!

www.highperformancehouse.com



Thanks to everyone who offered up suggestions. This is a great resource, you guys rock.