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Discussion Starter · #1 ·
My current MX6 GT turbo project keeps giving me the finger in one way or another. I guess the car is mad because I considered salvaging it. Anyway, the current problem is fuel flow or lack thereof at the fuel rail to the point yesterday that the car completely died, it restarted then died again. Currently, it will not start at all and the sparkplug I checked (#1) is showing little if any evidence of fuel ever reaching it. I'm going to check the other plugs at some point today for gas. The fuel pump tests good, the yellow relays click when the key is turned on and the fuel filter is brand f'ing new. BTW, before it died yesterday the car ran and sounded really good.

Should I assume this is something related to injectors, regulator or both?

I DO have spark so that is not the issue.
 

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Discussion Starter · #2 ·
Quick update: I pulled the remaining plugs and all of them had gas on them except for #1 as stated earlier. I'll look at the electrical connection next, although I doubt that's it because the car was up and running late last year, BUT with a different engine setup in it.
 

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The injectors are batch fired 2 X 2. Only 2 wires leave the ecu and pulse 4 injectors.
This means both wires leaving the ECU (Pin 3E and 3C) are crimped/spliced to another wire somewhere in the harness.

It is my experience that most issues with the F2T wire harness occur during an engine swap, from moving the harness out of the way to remove the engine, the harness gets moved and bent in ways it hasn't been since factory and the crimped/sliced wires in the harness can sometimes break.

To check the wire connections going to the injectors:
Use a multimeter and check that all four injector plugs have continuity on the positive wire (White/red).
Check for continuity on the ground wire (Yellow) between injectors 1 and 3.
Check for continuity on the ground wire (Yellow/Blue) between injectors 2 and 4.

To check if the fuel pump or fuel pressure regulator is the issue:
Block off the return fuel line and try running the car, if it runs and idles with the return line blocked than the pump is weak or the FPR is defective.

To check if the injectors are functioning your supposed to measure the fuel flow from the injector.
When the engine is running you can listen to the injector opening and closing with a mechanics stethoscope or a steel rod.
You can disconnect the wire connection on the injectors one at a time and see that engine speed decreases by 100 to 200 rpm each time.

The fact that it's the number one injector and spark plug is curious, if you are identifying your cylinders correctly (I think you are) Injector #1 is the only injector after the fuel pressure regulator on the fuel rail.
If it is a fuel pressure issues it is hard to tell if it's the pump or the fuel pressure regulator.
Can the fuel pressure regulator fail opened or the diaphragm leak 100% of the fuel back to the tank. It's really just a spring with vacuum boost assist. Vacuum helps open the diaphragm working against the springs pressure. Atmosphere (0vacuum) the diaphragm is under spring pressure only. Under boost every psi is added to the springs pressure against the diaphragm.
Theoretically the FPR should stay closed until fuel pressure in the rail is high enough to move the diaphragm, a weak or failing pump may never build enough pressure to open the FPR but even at 20 psi the car should idle.
 

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Discussion Starter · #4 ·
I changed all of the injectors to a set I had a history with and the FPR too. Considering, I am going to be selling the car I thought that was the best course of action. Additionally, I think there is/was some sort of minor eletrical gremlins going on that didn't help the fuel situation, but all seems well now.

On another note: while the tailpipe and muffler have been changed, the rest of the exhaust system is pretty much original OEM. The exhaust note is suitable for grandma if she were to buy it. ;)
 
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