This was a lousy day that ended in a tow home.

Yesterday I decided to treat myself to a nice digital timing light as my old SunPro would shut down at anything over 1800 rpm. My 928's timing was almost perfect at 22º but I decided to experiment and try 25º.
Went for a spin and was happy to experience a nice power increase with no pinging.
Drove to the nearest gas station about 7 miles away and filled up. Started the car and it died about 3 seconds later. Attempted several more times and no go.
Pushed it to a parking spot and started diagnosing but unfortunately all I had was the factory tool kit. Went with the old saying of "it's the last thing you worked on." Checked the vacuum lines, pulled the distributor cap, checked the green wire etc. No issues in that area.
Next I removed the test port cap off the fuel manifold and only a small amount of fuel leaked out. Bumped the starter, removed the cap again and no pressure.
Jumped the fuel pressure relay and all I get a loud thunk from the rear of the car. I'm screwed.

Called Hagerty (my insurance company) and they dispatched a flatbed and she was safely back at home in the garage within 45 minutes with no money out of pocket.

After ordering a new Bosch fuel pump, I decided to dissect mine...concerned over something from the fuel tank getting into it and jamming it up.
The pump was on the list of maintenance items from when I bought the car in 2011, so it only has about 12K miles on it.
First off, it was stalled and drawing about 20 amps. Also would not free up by reversing the polarity. After getting the end off, the commutator would not spin until I applied a lot of force and it finally broke free. No debris or damage in the commutator area so it had to be the pump section.
I hammered out the commutator with the impeller assembly and now it was spinning nicely. I disassembled the impeller and removed the 5 steel pucks and all were perfect.

The odd thing that fell out is the little UFO looking piece of plastic shown on the black cloth. It was at the inlet section and if you look at the impeller assembly to the right, there is no recessed area it would fit into.
It's also too large to fit through the inlet opening, so it could not have come from the fuel tank.
Any idea what it is? If you squeeze it, it's soft plastic and filled with air like a miniature float.
Bugs me that it was jammed up so bad with no signs of damage, wear or debris (other than that little plastic thing).

 

I have never dissected a fuel pump, but AWAG could be a check valve? To allow fuel flow in only one direction and keep the pump primed?

 

That thought crossed my mind but it doesn't appear to fit anywhere. It was just in the bottom of the metal housing. I think a by-pass valve is in the 5 o'clock position on the pump but it appears unrelated to that as well.

The main Bosch check valve is in the upper right corner of the pic.

 

maybe something that fell into it during manufacture?

 

the ufo is supposed to be in there. As far as I remember It avoids having actual airbubbles in the fuel pump as long as there is sufficient fuel in the tank and it can absorb small presure changes without pressure being applies to the pump housing.

 

That's sounds logical. It is like a soft bladder.