Problem Resolved [was I'm Stumped], Runs briefly, then dies & won't restart Options

[ThinAir]

Background: In preparation for last year's RRC I fixed the mounting on the MPS of my son's stock 1971 914-4. All seemed well until we went out for the Saturday morning run - we turned a corner and the engine suddenly died and was clearly flooded. It restarted quickly, but we had the same problem several times on that trip after that.

I assumed that I had disturbed something electrical on the passenger side of the engine and in digging around I discovered that the wire connecting the Cylinder Head Temp Sensor was corroded at its base (in fact it fell off in my hands). Ok, this is simple I said - so I bought and installed a new CHT.

Current Problem: The engine will start, but runs for only about 30 seconds before it dies. At that point it will not restart, but it smells of fuel as if it is flooded. I've checked for spark and I have spark. I've disconnected, cleaned and reconnected every electrical connection on the engine & relay board that I can find - including every relay on the board. The only connections that I have not checked are the connector where the FI harness connects to the brain.

Does anyone have any ideas on what could cause this and where to look next?

[wilchek]

First, I think you need to narrow down your search and work on one area at a time. First check the fuel pressure with a pressure meter. Harbor freight has them cheap and it will be fine for this purpose. To me it seems that you are thinking much worse than it is. Make sure the head temp sensor is good. IF you are flooding out which you are you should be able to remove the temp sensor and ground the line to the body and this will run at a fully heated setting (more lean). If the car still floods out then it is not the head temp sensor (sounds like this is not the issues). It sounds like one of you injectors are stuck open and the car is running for 30 seconds due to running out all of the fuel that is in the chamber. I think it is running with the MPS disconnected as there is still fuel in the cylinder. The injector can be stuck or the fuel pressure is too high causing the injector to leak. If the pressure is too high replace the pressure regulator, and make sure the return line to the fuel tank is not clogged. If these areas check out make sure the fuel injectors are not stuck open. So now we ruled out MPS, head temp snesor, fuel pressure and injectors. Last think to look at is the wiring. Clean all the contact at the board (which you did) and the ground contact under the airfilter at the base of the intake (all white lines). If this does not work I would bet it is the computer. I know they say that they never go but this is not true. swap a new ECU out with the quick connector under the grey door on the side of the ECU and go.

Steps to check

1. MPS ( sounds good)
2. Head temp sensor and wiring (sounds good)
3. Fuel Pressure (issues could be pressure regualtor, return line, fuel pump,and stuck open injector)
4. Injectors (stuck open)
5. ECU
6. Ground wiring

One of these things above is causing your car to flood out.