FP Gauge Working or Not?

[Funracer]

Yesterday I checked my system pressure by jumpering the FP and closing the valve on the pressure test setup. In this picture its open but you can see how its attached:

71 PSI which is mid spec.

Then removed the jumper wire and without thinking started the car again. Started immediately and rpm jumping around a somewhat. Then realized I had not opened the FP gauge valve. It was closed and the car was running.

Today I repeated this by opening the valve and starting car then took it for a drive everything was normal. When I got home left the engine running and shut the valve again. Engine kept running with wavering idle for a couple of minutes before I shut it off.

I was thinking in the past I had done this once (closed the valve with engine running) and the engine shut off immediately.

This is not a Harbor Freight FP tester. What gives? Or is this normal?

Thanks

[PeteKz]

Yours is a Lambda-CIS right?

If it's warmed up, it usually will keep running. It may not run well and will be hard to start like that.

[Funracer]

OK that is actually good news.

Thanks