Fuel PSI

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ramhunter9

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Well just installed the FP adapter on the quadzilla .

At idle 17psi
WOT 11-12 psi
Normal driving 13psi

With the raptor 150

Do these numbers sound OK
 

Mopar1973Man

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At idle 17psi
WOT 11-12 psi
Cursing 13psi

No there rather low... You only see about 2-3 PSI drop... But your dropping 6 PSI which shows signs of restriction or sucking air.

My AirDog 150 set for 18 @ idle and only drops to 16 @ WOT.
 
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ramhunter9

ramhunter9

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Teach me o wise one !

How do I adjust this issue ?
 
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ramhunter9

ramhunter9

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Scratch that ... found a diagram .. it has a adjustment screw ... I will adjust it to 18 at idle and see where that gets me
 

Mopar1973Man

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Hmmm... This has been a rather difficult one to hit a answer to every time. But I know the Raptor fuel system is nothing but quick connects. Eric over at Vulcan Performance told me about a sealing issues with the suction lines and how the fitting isn't design for suction. So getting to people have one stay in the cab and bump the starter while the other wiggles the suction line fittings carefully. The person in the cab has to watch for pressure fall occur while you jiggle the lines. Now I know you got a digital display so the display might update to slowly to actually show air bubbles. You might end up using a mechanical test gauge for this.

Another way to test is to pressurize the tank and look for wet spots...

Basically as you demand volume increases against the supply volume your pressure will fall. But I know the VP44 only takes about 20-25 GPH at WOT for the injectors the rest is sent back on the return line to the tank. So knowing this you pressure show stay pretty high like myself but if there is suction problems (air leaking in), kink lines, plugged filters, etc.

Oh thinking about that how about the line between the stock filter and the VP44 is that stock or 1/2"???
 
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ramhunter9

ramhunter9

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Yes all 1/2

I adjusted the pump and now it is 18-19 at idle
 
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ramhunter9

ramhunter9

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Holy crap ... almost to 5 psi at WOT ...wow

Be right back ... with a video
 
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ramhunter9

ramhunter9

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video

th_486e65a2.jpg
 
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ramhunter9

ramhunter9

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idle was at 18-19
normal speed 17
WOT 15 at one point for a split second I thought I seen 12 but was probably 15
 
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ramhunter9

ramhunter9

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Would it hurt to bump up the idle to 20 ?
That way I will be at 16-17 at WOT

Edit ... Bumped it to 20 psi at idle
Now WOT is 16-17

I think I am golden
 

Mopar1973Man

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Give me a bit video coming... I saw your I thought... "Ha! I got to show off mine... LOL" So I grab the camera and tripod and ran down the road for a 1 mile clip and hit 75 MPH both directions just flogging it. On the way back I sloshed the tank and suck a *** of air through the system as you see the gauge fall on its face. (D'Oh!)

But for 17.5 PSI at idle and hitting about 14.5 to 15 PSI at 75 MPH at WOT I'm still happy... I know a filter change is coming soon and I might have to check the regulator check ball in the AirDog its known to wedge in the spring time to time...

But I'll be back to post video.. :naughty:
 
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ramhunter9

ramhunter9

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LOL ^^

I just ordered a few donaldson filters form our Amsoil vendor at a fair price .. 21 bucks

Keep one in the rig at all times
 

Mopar1973Man

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Here you go... video...
Fuel pressure testing - YouTube

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ramhunter9

ramhunter9

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Show off ... lol

What was your boost at , at WOT
 
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ramhunter9

ramhunter9

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That is about where my boost gets on setting 8 on the quad at WOT
At 10 with it to the floor when I brought it home I saw 40 and **** myself never do I want to see 40 again
 

Mopar1973Man

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So you know got to dig into the problem you got with the fuel pressure fall...

I was thinking...

1. Do you have a needle valve before your sender to pretect it from water hammer pulses from the VP44?
Mopar1973Man's Dodge Cummins Articles - Fuel Pressure Gauge And Water Hammer Effects

2. Have you verified your plumbing is not sucking air in at the joints? You can pressurize the fuel tank by using a blow gun and rag in the filler neck don't get carried away with pressure though. A friend can crawl around under the truck checking for wet spots. The idea of watching the pressure gauge won't work because Raptor doesn't have a return line.

3. You might check the voltage at the actual pump using long test leads and watching the voltage as you drive. I've see na few ECM's randomly shut off and turn back on power to the lift pumps. So more or less test for voltage drop problems.
 
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ramhunter9

ramhunter9

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Good info ...

But all in all ya think my numbers are fine ?
 

Mopar1973Man

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They are usable just becareful of the amount of fall.
 
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