Flickering fuel filter light

[dale w]

When I start my truck the light flickers for a few seconds or sometimes longer. If I take off it stops. Is this a sign of something going bad. I replaced the fuel filter a month ago so .

[argve]

The light is connected to a pressure sender (on the clean side of the filter housing) so if it sees a drop in pressure either from a weak fuel pump or dirty filter it will turn the light on. If the wire comes off (disconnected) it will NOT turn the light on - but it would be a good idea to check it for shorting but since you say it goes off once you get rolling and I assume it does not come back on I highly doubt it's shorting out - but still worth a look see.

I would test the pressure coming off the pump at the filter head - 5 + psi is what your looking for. I want to say the flow is like a 1/3 pint in 10 seconds or so... Pete will be along here shortly with the data on the flow (memory a little foggy on the flow specs at the moment)

[fish36991]

CDNSARGUY posted on one of my questions:

Take the Schrader valve core out and hook a hose and pressure guage to the outlet.........crank engine see what you get for pressure, should have 4-6 psi from a good lift pump.

Volume test same place hook a hose to it crank over the engine 10 seconds you should get 1/3 pint of fuel minimum or 1 pint at 675 rpm in 30 seconds... engine running

Important the fuel shutoff solenoid (FSS) wire on the IP should be disconnected if you do not want a start just cranking. Re connect FSS after test complete.

Instead of draining the filter bowl, use the Schrader (tire) valve on the filter head.

This is not info from me but from CDNSARGUY who is obviously more experienced than myself. Just noticed you were looking at the same info he provided to me. Hope it helps,

Josh

[dale w]

If the pressure is low when I first start the engine. Is there a check valve on the lift pump that is failing. I don't know if this is related to this problem but fuel is moving from the back tank to the front tank. My mpg jumped on the front tank from 15.5 to over 19. My guage on my front tank is broke so I just run by mileage then switch over to the back. I noticed the bank tank was away a little lower then It should be.