Pressure Switch?

[waytallwhitey]

What are the symptoms of a bad fuel pressure switch? I was headed home last weekend; 325 miles on a new filter and clean pre-filter. Just an hour into my trip and the green light starts flashing rapidly; not intermittently like when the filter starts to go south. So I shut the system down and drive home on diesel. Once I get home I pull the pre-filter and it’s practically spotless, but I changed the filter anyway as I want to eliminate as many variables as I can.

Any input here? How big a pain in the arse is it to change the switch? Spare time is the one thing I don’t have when I get home; I’m only here for Saturday and half of Sunday before having to head back to the city.

[BruceM]

you need a fuel pressure gauge.

[waytallwhitey]

you need a fuel pressure gauge.

[Longstroke]

+2 for the fuel pressure gauge.

Symptoms vary at least it did for me when the pressure switch malfunctions.

I have a OBS truck and when the switch quit the first time the diesel pump would not come on. To get it working again I had to use the jumper thats supplied with the V3.

Went though 2 of the newer style switch's and when they quit the V3 wouldn't come on due to the switches not being able to handle the current to the diesel pump.

So I installed a pressure gauge now I know whats going on with the system and when it's time to change the filter on the V3 or the diesel side.

The gauge tells you the pressure of of the fuel that your running so there's no guessing whats going on with the system.

Good Luck

[BruceM]

LOL I was waiting for that.

Something you can try, figure out which is the pressure switch on your Fancy vegistroke, pull the plug and jumper the pins on the plug. Go for a ride in your truck and manually switch on the system. If it runs fine at all mph/rpms then it sounds like your switch is the likely culprit.

when I had a plugged fuel filter on my truck on the diesel side I couldn't go much above 30mph with the pedal to the floor, there was just no fuel pressure to feed the injectors.

In theory if you bypass the pressure switch and really give your truck a bit of a workout, and it dosen't want to go then you would have low pressure from a restriction, bad pump, or bad filter. If it runs and drives like normal then it's gotta be your switch.

If it's just the switch you could drive back down to Yonkers with the connector jumpered. If there isn't enough fuel to fill the injectors your truck will just slow down.

also make sure any vent cap/port on your WVO tank isn't plugged. read some stories on various boards where people will have problems cause of buildup on the vent causing a vacuum in their tank.

[Jack_Toepfer]

Whitey - The gauge is still overrated.

You need a switch. When the light flashes slower on colder oil and goes away when its really warm, then you'll need a filter soon. If the light is solid and operating normally, the filter is good and everything is great.

The gauge wouldn't tell you much more than that.

[lancaster,pa]

Have to agree that you can get a lot of info from the light? - Patrick

[waytallwhitey]

+2 for the fuel pressure gauge.

Symptoms vary at least it did for me when the pressure switch malfunctions.

I have a OBS truck and when the switch quit the first time the diesel pump would not come on. To get it working again I had to use the jumper thats supplied with the V3.

Went though 2 of the newer style switch's and when they quit the V3 wouldn't come on due to the switches not being able to handle the current to the diesel pump.

So I installed a pressure gauge now I know whats going on with the system and when it's time to change the filter on the V3 or the diesel side.

The gauge tells you the pressure of of the fuel that your running so there's no guessing whats going on with the system.

Good Luck

I didn't get a jumper. I just am wondering what symptoms I should be looking for if the switch is bad

[Longstroke]

I didn't get a jumper. I just am wondering what symptoms I should be looking for if the switch is bad

You should have got the jumper with you V3, it's a plug with a short loop in it. If the diesel pump will not come on due to a bad switch you simply unplug the pressure switch put the jumper on the wire going to the timer boards.


When the first switch went bad my green light would not go off, the next two switches would not turn the light on when they went bad, they blinked some then just quit.

There's good thread or two around here somewhere about pressure switch problems.