Our 2001 expy has been sitting a while and tonight I tried to start it.

The engine cranked just fine and fast, but wouldn't start.

I checked the Schrader valve on the passenger side fuel rail and there was no pressure [no fuel spurted out].

I pulled the fuse [#10, 20 amp] it looked OK.

Put a cheap digital DVM [Harbor Freight, $4, great meters for the $] on the 10 amp scale across the fuse holder and turned the key on and saw a current draw of 17 amps for about 2 seconds. [Suggesting the pump was drawing current and trying to run]

Listened for the fuel pump running with the fuel cap removed, wasn't running.

Then took a rubber hammer and beat the crap out of the bottom of the fuel tank while my SO turned the key on and off.

Still no run of the pump.

Swapped relay 301 [fuel pump] with 303 [wipers] and tried -didn't run.

Hit the fuel tank some more while SO turned the key and all of a sudden I heard the pump run.

Swapped the relays back to original position.

Pump still ran.

Note --pump drive circuit is designed to cause the pump to run ONLY a second or two each time the key switch is turned for safety issues.

After the pump started running engine would start OK.

I think the hydraulic shock from hitting the tank combined with the electrical pulse trying to spin the pump caused the pump to break free and run.

[I've seen the same thing happen with a small John Deere tractor and pulled the tank and the pump with no visible issue. It's worked fine since.]


Now some QUESTIONS...

How many think the pump will fail again soon? [everyone?]

Does anyone think something else is going on besides the pump being intermittently 'stuck'?

We use the expy for trips and I'd like to create an access hole thru the floor board to access the pump asm to facilitate a quick fix while on the road if it fails. Does anyone have thoughts or have done this?

Would someone post the schematic of the fuel pump circuit so we can see if 'modules' or other components besides the relay are involved? My shop manuals are in another expy a couple thou miles away.

Thank you all in advance!!

 

One other clue for folks having problems.

As mentioned above, when I measured current across the fuse holder [w/ the fuse removed] while the fuel pump wasn't turning, the current was approx 17 amps [locked rotor] for the 2 seconds or so it was energized when first turning on the key.

After the problem was fixed a little while ago, I was curious what the running current was for the pump.

Measuring it the same way with the same meter, the running current is approx 5 amps.

Important info when diagnosing and can save you BIG bucks understanding the problem and fixing it yourself.

 

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