PSI & Lift Pumps

[GM Smitty]

You fellas running lift pumps...what sort of device are you using to measure pressure (psi)? Is this the same gauge that others are using to check restriction of the fuel system?
Thanks.
Josh

[chuntag95]

I bought a cheap gauge that measures 30"Hg to 15 PSIG. I put it post Mega and set up my pressures with the gauge at room temperature. I was right before the inlet on about the same level as the Schrader valve. I have the gauge on the top of the Mega now, but only read it when it's cold. The temperature get's to it and changes the readings. I am waiting on JK's gauge to be my final go/no go gauge. I think both Tommy (abear) and Bill have the Kent Moore high dollar GM gauge for their setups.

[a bear]

I use a slack tube manometer. A little old fashioned but the reading in always dead on. I'm running a 12" head of diesel (.364 Psi) @ 1/4 tank of fuel. The pressure had been so reliably steady I hadn't checked it in a while. Still waiting on JK's gauge so I can check it at the shrader valve and catch my fuel sample. :D

Chris,
I see you've been heavy on the honey do list. I guess it's safe to assume you're gas free. tongue.gif

[ 07-03-2003, 09:01 AM: Message edited by: a bear ]

[chuntag95]

Heavy? :confused: My list is about to CRUSH me! :eek: I have been busting you know what for the last 4 weeks straight. I got my fan today for the Alli cooler, but it's too big. I will have to modify the mounting bracket if I move forward. I am thinking about the second cooler now instead. :rolleyes: Taking her in on Monday to have the tranny, AC and injectors checked before our vacation. The list never ends.....

To actually answer your question Tommy, YES! :D Still gas free. I have not had good mileage for this tank. I am wondering if the air staying in solution is the cause. Hey, do you have a picture of your tube?

[jbplock]

Josh,
I have a low cost ($13) Vac/Pressure gauge (http://community.webshots.com/photo/77018086/78007628dTiRDx) (from MSC) on the Mega bleeder similar to Chris’ except it’s not liquid filled. It’s about 2 inches in diameter with a 30inHg to 15 psi scale. With the large range on the scale, the resolution around zero is not very good, but it provides the ability to quickly monitor vac/pressure within 1 psi or 1inHg. I also have the GM Kent Moore gauge (http://community.webshots.com/photo/73314886/73315108BBKdiI) that attaches to the schrader valve. I used this to set the lift pump (http://community.webshots.com/album/77018086bLHHHC) pressure at the schrader valve as close to 0 psi as I could get it (currently about 0.2 psi). Each tic on the Kent-Moore is .4psi and just moving the GM gauge will cause the reading to vary a few tenths. I always lay the gauge on the air filter to get a consistent reading. Every time I've checked the gauge on the bleeder, it has tracked well with the Kent-Moore.
smile.gif

[sdaver]

ok guys Im confused........I have installed the fm100 with the 5 micron prefilter and the 2 micron filter post lift pump but pre oem........what are you guys using to regulate the pressure to the injector pump.......mines just running at what ever pressure fm100 is supplying thru the 2 micron and the factory filter......I have the ability to totally bypass the pump and go back to factory setup but I don't know if the valves will work partilly open :confused:

[CntrlCalDmax]

I have a 0-15 psi liquid filled 2.5" gauge temporarily (for the last 12,000 miles) mounted in the cab so that I can monitor while driving. I sample pressure at the outlet of the lift pump and run 3 psi at idle.

BTW, made the best milage ever last tank, 19.9 mpg, mostly commuting. Maybe some day I'll see 20. smile.gif

[CntrlCalDmax]

sdaver,

I am running a ball valve in parallel with the pump. It acts as nothing more than an adjustable fixed orifice to bypass a portion of the fuel and lower pressure. Also can be used in case of a pump failure to allow normal fuel flow from the tank. Many are using a needle valve instead of a ball valve which is probably easier to adjust.

[GM Smitty]

Thanks for the replies everyone.

sdaver - I was wondering the same thing? I think, emphasis on "I think", most are using some sort of needle valve to regulate the flow through the bypass, therefore affecting the psi of the fuel at the schrader valve. Can someone correct me if I'm wrong.

Where can the Kent-Moore tool be purchased? I've heard pricing ranging from $140 to $200.

Josh

[sdaver]

cntrcaldmax
I would sure like the oppurtunity to talk with you on the phone call me collect 205 xxx-xxxx...Ill edit this later and remove the number(If you accept this mission the thread will dissapear after you call).....thanks dave

Thanks so much for the call....will bypass as we discussed in the morning....you have a new friend in alabama........thanks again :D dave

[ 07-02-2003, 09:43 PM: Message edited by: sdaver ]

[a bear]

GM Smitty,
You are correct on the bypass needle valve to adjust pressure. You can see the needle valve location in the below lift pump pics.

[chuntag95]

GM Smitty,

I have lots of pictures as well at Web Shots (http://community.webshots.com/user/chuntag95) that you can look at. My gauge is 2 1/2" diameter. I have one that is liquid filled and one that is not. The not one is currently on the truck. I have not taken any pictures of the setup since I move it off the engine to the top of the Mega. Let me know if you would like to see a picture of it.

It has been really nice not having diesel hands from bleeding and drips. :D

[sdaver]

ok I got a 2&1/2" liquid filled gauge plumbed into the second filter output to oem fuel line and a needle valve plumbed from the second filter output to the second pump input. turn of the needle regulates the orfice size which in return regulates how fuel returns to the pump. I have the oem filter recieving 2 psi.......unregulated it was 5 psi.......have not checked at shcrader dont have a guage that fits there yet. thanks gben and centrlcaldmax :D :D :D dave

[ 07-03-2003, 08:59 AM: Message edited by: sdaver ]