Just bought a truck 2 weeks ago while on leave. And have read a lot about insuring fuel preasure from lift pump is present, so I ordered a warning light from blue chip and it is set for I believe 4-5 psi. I am now reading in some post responses that you should have at least 8-10psi.

recomendations anyone

 

8 PSI is my min. @ WOT, but if the light goes off at 5 you'll be fine. If you see the light go on replace the pump, don't think it will fix itself.

Thank you for your service to our country.

 

I have heard the same as above from others on the site. The main man at Cummins here in KC told me that anything above 3.5 was fine, though he didn't qualify that at any given RPM or throttle.

T

 

ya - send back the pressure switch and get yourself a mechanical fuel pressure guage, so you can actually see what the fuel pressure is

 

5 psi is generally accepted as the minimum WOT FP but most of us like to see a bit more than the minimum......it makes us feel a bit better. This is typically why you will hear people say to have more than 5 psi as the minimum WOT FP - nobody likes the feeling of running on the edge! I 2nd the good Dr.'s suggestion of skipping the warning light and installing the gauge. I much prefer the gauge so you actually know what your LP pressure is instead of just having a light that comes that only tells that there is too little fuel pressure and still not knowing the actual pressure.

 

I'm not to fond of the dummy light idea...

It's kind of like on a Honda motorcycle. The oil light comes on at 5 PSI or less pressure. Well one day you will be haulin' down the pavement and that light will pop on and it's to late now... You done the damage to the engine...

Well the same applies to you VP44 it could be hovering at 6-7 PSI for a long time before it trips the light. Like in my last LP it was idling at 11-12... Cruised at 6-7... WOT 4-5...

And with the price of a VP44 pump I would only use a light together with a pressure guage.

 

I tend to agree with him.

 

Another thing about the pressure switch/light - a member here tested three pressure switches that he ordered and found that they were all out of calibration from where they are supposed to be. Calibration of pressure switches can drift and then you have no idea how much fuel pressure you have - just too inaccurate.

 

Huh, I wasn't thinking of this part. THIS is a good argument for getting the gauge rather than the light. Good point!

 

That's interresting... and the first time I heard that one... I guess its a good thing to remeber and pass on to others...

 

Cant say for sure because its second hand info and I havent seen it myself - but the guy that posted this is an Instrument Tech. A pressure switch would be a decent idea if you had access to pneumatic calibration equipment so you could check/adjust the setting.

 

Either way, being able to SEE fluctuation and/or drop is key. There is no fluctuation to on or off (the light).
I was considering getting the light in addition to the gauge just incase I ever (highly unlikely) let someone use the truck.

 

thanks all, for the input. I think I will install both a light and a guage.

grant

 

Yes, that is a good idea.
I have had two different gauges on and they were 4 psi difference.

 

It might be a good idea to keep them both. My truck has a issue of sometimes not starting the pump when the key is turned on or the pressure will be low at the initial bump. That is with 3 different lift pumps! Two of those have good pressure while they are running most of the time. The point is that the light might get your attention when a part time problem occurs that you might not catch with the guage.