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Discussion Starter · #1 ·
I just in installed my Raptor 100 with 1/2 in lines yesterday. The lil intank pump was pushing 7 idle/ 5 cruz/ 0-3 WOT, now I am running 19 idle/ 17 cruz / 14 WOT. Now Just idling I've noticed it seems to shake harder through the steering wheel and driving it reminds me of having 4wd on with the feeling of the transfer-case moving. Also my rpm gauge dosent seem to flicker as much( at idle, tack will bounce hundred rpm) and feels smoother but when downshifting I notice the vibration as well.

Now my question being would the extra psi cause this?? Or am I high and everythigs normal..
 

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in my experience if you think youre high, you probably are. LOL

re check all the fittings and make sure you arent getting any air into the system
 

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Do you have any codes present? How is your power and economy? Having run such consistently low fuel pressure (7psi idle, 5 psi cruise, 0-3 psi WOT :shock:), I would be very concerned about damage to the the VP44...

Over time, low fuel pressure to the VP44 can damage the diaphragm in the front of the pump, causing the timing piston to vibrate. The rotor may also have issues, causing cavitation. The increased fuel pressure from the Raptor pump may simply be bringing existing problems to light.
 

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Discussion Starter · #4 ·
in my experience if you think youre high, you probably are. LOL

re check all the fittings and make sure you arent getting any air into the system
Haha you might be on to somten :) But I just opend the drain valve for few seconds and stream of straight fuel was coming out.

Do you have any codes present? How is your power and economy? Having run such consistently low fuel pressure (7psi idle, 5 psi cruise, 0-3 psi WOT :shock:), I would be very concerned about damage to the the VP44...

Over time, low fuel pressure to the VP44 can damage the diaphragm in the front of the pump, causing the timing piston to vibrate. The rotor may also have issues, causing cavitation. The increased fuel pressure from the Raptor pump may simply be bringing existing problems to light.
Interesting.. I have no codes thrown, starts up instantly, getting 19.6 city,plenty of power figuring I just now started to turn my quad up ( lvl 4 lol ). But I do believe that I have OEM VP44 but not certain.

But it's only been a day so maybe there is air somewhere.. cause I hope VP not dying yet, got a 2k trip next week back to Indiana. :shock:
 

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With no codes, immediate starts, 19.6 MPG, and no seeming loss of power, your VP44 is most likely okay... :thumbsup:

Check things over, and keep an eye open for issues. There's a good chance nothing at all is wrong. If it makes you feel any better, when I swapped in new injectors, they minutely changed the idle characteristics of my truck to where the normal vibration in the steering wheel / brake pedal felt slightly different. Sometimes performance upgrades can manifest themselves in little ways like that.
 

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Discussion Starter · #6 ·
Haha a little, but it's not a bad shake just more noticeable. I also did have small leak by my VP at fuel pressure sensor.

Maybe it's shaking more cause it's actually getting adiquit fuel? I did notice my EGTs lower faster at idle as well..
 

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Maybe it's shaking more cause it's actually getting adequate fuel?
Based on what's been discussed, that's exactly what I'm thinking...

Take care of the fuel pressure sensor leak (which I'm sure you've already done), and you should be good to go.
 
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