Revs dip on light throttle, Otherwise perfect! Options

[gturner008]

A little bit of experience and wisdom needed.

I’m new to 914 - so don’t know if this is normal for the 2.0 1976 engine.

Engine runs perfectly. Great starter. Smooth and easily revs. Very happy.

But I noticed when it’s ticking over - and I gently rest my foot on the throttle - and apply a tiny bit of pressure, the revs dip - and it almost wants to die.

Apply more pressure or quick pressure, and it picks up perfectly.

Any ideas on what might causing this? Or is it a characteristic of this engine and injection system?

Very grateful for any thoughts. Thanks. Gary

[PlaysWithCars]

The trace for the "accelerator pump" isn't your problem. It has the same function as an accelerator pump on a carburetor only instead of moving a diaphragm to squeeze extra fuel into the air stream, it cycles the injectors open and closed. It only works to add extra fuel as the throttle is being opened, not to enrich it at a fixed throttle position.

If I recall correctly from my '74 2.0, the other traces on the board are used to sense throttle position and inform the fuel injection ECU so it can supply the right amount of fuel based on throttle position and load (measured by the manifold pressure sensor). Someone else suggested checking the adjustment of the throttle position sensor. I think that is where I would start. My guess is that it isn't changing resistance when you move the throttle very slightly off of idle. The result is extra air entering w/o the computer knowing to add extra fuel.