I installed a new Westach FP guage about two weeks ago. I think it is acting funny. At idle I have 16psi, but sometimes when cruising at low rpms the guage will go up and down slowly from 12psi down to below 0psi. Then when I hammer it it comes up to 10 and goes down proportionally with rpms. What should happen at WOT? I had the pump checked for pressure, but when the dealer checks for pressure they are not checking for volume, which is just as important.

 

How do you check for volume?

I turn my key on, and the gauge goes to 15psi, then promptly falls to zero.

The truck starts quickly. The pressure goes to 15psi at idle.

8 psi & wot.
11psi & 70mph cruising
14-15 @ idle

oh yeah....i have a westach fp gauge.

 

I also have Westech. One thing I noticed after I instelled it, is the wires were not quite long enough to the sensor. Everytime the motor would torque, my gauge would act up. Since I have lenghthened the wire, and made sure of tight connections, I have not had any problems.
Idle: 15 PSI
cruising: 12 PSI
WOT: 10

 

I have a fairly new lift pump, a 7lb pusher pump and large banjo fittings and bolts.

When I turn the ignition switch on without cranking it spikes to 10+/- lbs then drops to 0.

Start it and it runs a little below 20 until the heaters quit cycling and everything warms up, then it is around 21+lbs at idle.

Crusing it is in the 16 to 19lb range. If I get in it, it can pull down to as low as 10+lbs.


My gauge is mechanical - if yours is electric there may be an issue with grounding or vibration of the sending unit.

Good luck,

George

 

Where did you install the transmitter? I installed mine on the wheel well using an 18” X 1/8 npt grease fitting hose. My pressures are always nice and steady. I don’t have to worry about the VP-44 vibrating my transmitter to death.
15 - 16 psi at idle
12-14 psi at 70 mph
8-10 psi at WOT
The pressures are higher in warmer weather.

 

My transmitter is mounted on the intake horn hose clamp. I don't think vibration is a problem. First I will change my fuel filter. What filter should I use? What oil filter should I use? I think the lift pump is cutting out, unable to keep the pressure up in a high volume situation.

 

Using your finger, tap on the wires at the sensor, while someone else watches the gauge. this will rule out the loose connection. As far as which filters, I only use Fleetgaurd filters since Fleetgaurd is a Cummins company. You can get them from a couple of sources like a local Cummins dealer, or there are places on-line. I get mine from Genos Garage http://genosgarage.com/ for $71.00 plus S/H for a 'filter kit'. They also have the kits-air filter for a little less.

4 - LF3894 - Stratapore Oil Filters
2 - FS19579 - Fleetguard Fuel Filter (new filter supersedes FS1268)
1 - AF25541 - Fleetguard Air Filter

 

Mine reads fuel pressure. I don't know what yours does.

 

You said what i was thinking

 

I have a pressure question also. I put in a 0-30# pressure gauge in the 1/8 NPT fitting on top of the fuel filter housing. It goes to 12PSI before it starts, then drops to zero after it starts. One time it was at 11 at idle, but not it only registers before it starts. The truck has always run very strong with no problems at all. I leave the guage in all the time and it might be failing from the vibration, but you would think it would not work at all. I've ordered a new pump to be on the safe side. I'm confused, any ideas anyone?

Where do you usually mount the fuel pressure sending unit?

 

This has worked problem free since mid 2000. I had the lift pump replaced under warranty when I started seeing it drop down to 5psi on hard pulls. I also have the -8AN Wildcat SS fuel line upgrade now and I never see pressures below 12psi (That's pulling the 5er up steep grades @ 2600-2900rpm)


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