Engine died at autocross event, How embarassing! Options

[toadman]

RESOLVED - See last post by me.

Background - I put my car up for the winter early last December. Car is a 1976 914 with stock fuel injection. Filled it with gas and some Sta-bil fuel stabilizer. Car was running very well when put up. In March I replaced my Pertronix Ignitor with a Compu-fire unit. Car ran well around the block but did not have much time on the Compu-fire until recently when I drove it to a local autocross event.

Drove about 30 minutes to the event with no problems. I made one run and got in line for the next one. Idle started to fall while I was in line. This was not unusual as the car has a history of a weak idle when hot. Car ran well for run two but the engine died on the way back the line.

I had no idle but I could get the engine to run (poorly) if I gave it lots of gas. Exhaust was very rich. I carry a lot of spare parts all the time, including a known, good MPS. I replaced the MPS but it didn't help. I could not diagnose the problem at the event so I got a tow home.

What I have done - I removed the distributor, cleaned things up a bit, including the trigger points, removed the Compu-fire unit and installed points and condensor and reinstalled distributor in engine. No change.

I got my hands on a VW/Grundig fuel injection tester and everything checked out OK except one thing - test number 15 indicates "Open circuit, poor connections or defective pressure switch". The repair instructions were "Check pressure switch, connections and cables. Replace pressure switch if necessary. Look for modified wiring harness". This is not unusual as I have identified this condition in the past and the car ran well, except for the weak idle when hot, for years until now. I have had this harness out of the car for evaluation and I am aware of a short splice of black/purple wire from the FI harness to the negative coil terminal. I know this is a soldered splice as I made this repair.

I used a timing light to confirm spark at all cylinders.

I replaced the fuel injection brain with a known, good unit. No change.

I replaced the cylinder head temp sensor with a new unit. No change.

I cleaned the grounding point beneath the relay board behind the driver's seat, the battery-to-body ground and the fuel injection grounding points on the engine block above cylinder 3. No change.

I removed electrical leads, one at a time, from the intake air temp sensor, the thermo-time sensor, cold start valve and the TPS. No change.

Observations - After trying to start the car, plugs 2 and 3 are wet and plugs 1 and 4 are dry. Does this mean that there is no combustion at cylinders 2 and 3? When I removed the passenger side (cylinders 3 and 4) intake runners to clean the FI grounding point, both intake runners were wet with gas.

I am totally stumped and would appreciate any advice.