Raptor 100 - Inconsistent Fuel PSI

Tejas TJ

Tejas TJ

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Apr 17, 2009
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Just finished installing my Raptor 100 w/ quick-connects and the Draw Straw V and now I'm getting strange fuel PSI readings everytime I start the truck up. I've got a mechanical Dipricol fuel PSI gauge with a needle valve, so it's not the gauge. I looked around for fuel leaks and couldn't find any. Some member on youtube posted a video of his inconsistent fuel pressure readings with the quick-connects and once he changed over to JIC fittings it solved his problem.

This is where the needle settled after 3 consecutive start within a minute...

1st start.

431085_10151220859580331_604235330_22602813_1055940541_n.jpg


2nd start.

418579_10151220857760331_604235330_22602810_160645505_n.jpg


3rd start.

420643_10151220851735331_604235330_22602798_402736086_n.jpg
 
Does yours have a regulator? If so try playing with that a bit maybe you have a little bit of air in your gauge line giving you inconstant readings. Also take a pic of the fittings you have and post them.
 
Could be a weak/sticking OFV also. The only thing i use those type gauges for is to make sure i have fuel pressure
 
Ok, well I'm leaning towards air in the gauge line.

To bleed the air out of the line, could I just unscrew the needle valve until fuel runs out and then close it back up or do I have to crack it at the gauge?
 
I was going to make my own thread about my raptor 150 fuel pressure fluctuating but I figured I'll just post here. Fuel sump and 1/2" braided lines, I'm not using any or the airdog fitting in the kit, the pump is pushing through a 2 micron filter and water separator and the gauge is at the Y before the Cp3's.
[ame="http://www.youtube.com/watch?v=69EcpCwohYw&feature=youtube_gdata_player"]Airdog RP150 - YouTube[/ame]




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Cummins610...you got some **** going on! Not sure but my mechanical gauge does not move at all and I have a airdog with there 1/2 inch fuel lines and there fittings. Not sure how your gauges are setup but I have a 1/4 line made out of the same line that airdog recommends. It goes to a metal regulator looking thing I can't remember what it's called but it does not flow diesel into the cab to the gauge. It has a diaphragm in it. On the other half there is another line that goes to the gauge and it is filled with antifreeze. When I installed it I bleed the fuel line by starting the truck and cracking the line that went to the regulator looking thing. If you shoot me your number I can send you a video or is someone want to explain to me how to upload one I can do that to.
 
Also you might want to move this post to the airdog thread so they see it and maybe give you an idea as to where to start for both of you.
 
You have what's called an Isolator. Those have been proven to be a pain in the butt. I would rather run a needle valve any day, unless it starts leaking in the cab of course.
 
I was heading home today and from a light getting up to speed fuel pressure dropped to 0 then to 5, 15 and then settled at 10. It sat at 10 the rest of the way home. What's up with this pump?
 
Also when you installed your draw straw did you gut all the stock restrictions out of the canister? If not that may be your issue. Draw straws suck get a sump if that is the issue.
 
Messed with it tonight.

1. I had both batteries and the altenator (14 volts) tested, all checked out good, power wires are tight, ecm wires are tight.
2. Checked the return line off the motor to the fuel canister and it was tight.
3. Took the new Vitron ball out of the regulator and it checked out.
4. Took the bottom off the pump and checked the gears for trash, nothing.
5. Bleed the fuel to the mechanical fuel pressure gauge. (when I adjust the regualtor a little the fuel pressure gauge moves with each little adjustment)
6. I then retightend all fuel pressure gauge fittings.

Here are some videos...

What would cause the gauge to drop PSI so slowely when I shut the truck down (The needle valve was open a nice bit)?

raptor 100 start and idle - YouTube

Fuel PSI gauge is in the middle, watch it move from 18 at idle and drop like a rock when the torque converter locks. Sorry for the shakes, steering a 2nd gen dodge one handed gets squirrely.

Cummins WOT Raptor 100 Fuel Pressure - YouTube
 
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