Heavy gas miss

[rodo]

Well, after a long time, the turbo is running. Mostly okay driving (so far) but getting on the road has coincided with an odd miss. With a light foot, the car accelerates fine and smooth. If I keep a light foot and not shift right away, the engine will continue to increase rpms as I speed up. But, if I try to put a bit more on the gas pedal, I get a quick shut down. Originally thought this was distributor, when I thought the problem was the rpms of the engine. But now I think it fuel. What in in the world is sensed by whatever sensor that cuts off the fuel flow? Or is it airflow as I put the pedal down? I'm stumped.

[Nut124]

Sounds like the fuel system is unable to keep up at high demand.

To confirm, you could plumb a pressure gauge with a long hose in the fuel line just where it enters the rail and place it so you can see it while driving.

[rodo]

Not sure it is unable to keep up at demand: new pump, filters, injectors. Seems, b/c it is so sudden, that it is more like a cut-off. But...what in the world would cut off fuel supply?

[rridge]

The turbo has a series of 4 manifold pressure sensors that enrich the mixture as positive manifold pressure builds. One of them is an over-boost protection that shuts off the FI completely when a boost pressure beyond 6-7 lbs is detected. So if the symptoms show only under boost, the pressure switches are the place to look.

[rodo]

Thanks, Richard. I had my suspicions about those. Time to check them.

[rodo]

And I'm sure that you, Richard, have mentioned that those switches are long gone. Did you ever find something that would work similarly to replace them?