ClassA4x4

I've just returned from a 10-day 4x4 trail trip in Baja, around Bahia de Los Angeles and among others encountered the FSS problem. I had a spare FSS with me and performed field repair in the boonies; Here's what I learned. I had the #2 malfunction below.


Fuel shutoff solenoid (fss) operation

At ignition off, the free floating valve drops into the fuel path, closing the fuel flow, and preventing the engine to run. *At ignition on or run/start mode, 12V is supplied to the solenoid and creates an elecromagnetic field that retracts the valve from the fuel path, allowing fuel flow.

The solenoid valve consists of a cylindrical plunger with a spring inside it. There is a conical rubber at the bottom tip of the cylinder; *this provides a good seal to cutoff fuel flow when the solenod is de-energized. A dead solenoid and a leaking conical *rubber tip are common problems.

The fss may malfunction in 3 different ways:
1. *Dead/open solenoid coil, good rubber tip, fails to energize and retract the valve - this causes a no-start condition
2. Dead/open solenoid coil, leaking rubber tip - this causes a no-shutoff condition. Good idle but engine won't reach upper rpm potential, depending on the size of the leak.
3. Good solenoid coil, leaking rubber tip, retracts the valve but causes a no-shutoff condition. Normal idle and rpms.

BC847