Installed the Raptor yesterday and it was running fine at 18 psi until this evening when I took the truck to the car wash.. after pulling out I noticed the fuel pressure gauge was reading 16 psi.. 5 minutes later.. 15psi.. by the time I got home it was down to 8psi.

Got underneath the hood and noticed one of the fittings was leaking a bit.. figured that's where the pressure loss was coming from, but I took it all apart and re-did the teflon tape.. put it all back together again.. dry as a bone now, but only reading 7psi. Turned the screw on the pump up.. but no change in pressure.

Any ideas? I can't imagine a pump that sits on the frame of the truck wouldn't be able to handle a car wash?!

Got a different pressure gauge?

Got a different pressure gauge?

 

I don't unfortunately.  I'm using an ISSPRO EV mechanical gauge - no change with it.. made sure the air was bled out after re-doing the fittings.  I suppose it's a possibility though..

Is your fuel pressure gauge new as well? Does the truck start right up after it's been sitting? If not you've still got an air leak somewhere, if it does start right up I would call Air Dog and inform them.

Birchy, I have an '01 CTD auto w/ AD II, mounted on the frame. Installed about a year ago, it was supposed to control at 15 psi but had 5-8 psi initially, per my MaxTow gauge w/snubber and electronic sender. After several weeks of worrying, I screwed the adjuster in 2-3 turns with very little improvement. I took the relief valve adjuster out and found the spring inside was very flimsy. It would not apply enough force to the sliding piston in the relief valve to build that pressure; if the adjuster was screwed all the way in, the adjuster stem could push against the sliding part of the valve and create a fixed orifice which could REALLY raise the pressure,which is NOT good, could over-pressure the PV45 injector pump and kill it. Contacted AirDog- they sent a replacement spring that holds the relief valve in but it was for the old AirDog and wouldn't fit- diameter too large . Checked with them again and they sent a different spring, stiffer than the original and the right diameter. I replaced the flimsy one with this, and then was able to easily adjust the pressure to 16-17 psi, or anything else i wanted it to be. Just saying- the pressure adjuster on the Raptor looks the same externally as my AirDog II, so perhaps yours has the wrong spring; the ID on the bag the good spring came in is:"1V-00034: spring, 71906s A/D II 15psi". Their parts line is 317-421-3180. This may help.

Is your fuel pressure gauge new as well? Does the truck start right up after it's been sitting? If not you've still got an air leak somewhere, if it does start right up I would call Air Dog and inform them.

 

Yes, brand new out of the box.  The truck does start right up, so I don't think it's an air leak.  I actually did email Pureflow last evening around the same time I made this thread, and they emailed me back this morning already.

 

Birchy, I have an '01 CTD auto w/ AD II, mounted on the frame. Installed about a year ago, it was supposed to control at 15 psi but had 5-8 psi initially, per my MaxTow gauge w/snubber and electronic sender. After several weeks of worrying, I screwed the adjuster in 2-3 turns with very little improvement. I took the relief valve adjuster out and found the spring inside was very flimsy. It would not apply enough force to the sliding piston in the relief valve to build that pressure; if the adjuster was screwed all the way in, the adjuster stem could push against the sliding part of the valve and create a fixed orifice which could REALLY raise the pressure,which is NOT good, could over-pressure the PV45 injector pump and kill it. Contacted AirDog- they sent a replacement spring that holds the relief valve in but it was for the old AirDog and wouldn't fit- diameter too large . Checked with them again and they sent a different spring, stiffer than the original and the right diameter. I replaced the flimsy one with this, and then was able to easily adjust the pressure to 16-17 psi, or anything else i wanted it to be. Just saying- the pressure adjuster on the Raptor looks the same externally as my AirDog II, so perhaps yours has the wrong spring; the ID on the bag the good spring came in is:"1V-00034: spring, 71906s A/D II 15psi". Their parts line is 317-421-3180. This may help.

 

Good to know, thanks.  I'll keep that in mind when talking to them.

Pureflow is sending me a replacement Raptor 100 and a prepaid return shipping label. Hopefully the new one will tide me over until I can save up for a FASS Titanium.

Ive replaced about 6 raptors and the last one was replaced 6 months ago. So the replacements I have done are still working

Edited September 23, 201410 yr by mopartechnician

Ive replaced about 6 raptors and the last one was replaced 6 months ago. So the replacements I have done are still working

 

Good to know.  I appreciate your input on the last couple threads I've posted - thanks!  I had done a bunch of research 2 years ago before going with the Raptor..  I knew it wasn't the BEST solution, but reviews seemed to be pretty decent, so I figured it would get me by until I could save up for something better.  I'm hoping that's still the case.  By the sounds of things, I just got a lemon.  I've seen quite a number of people here - and on cumminsforum - that have had good results with them.

I'd get a mechanical test gauge. Vulcan sells them. Takes the guess work out if it. If you're running an isolator I'd be really suspect of a proper reading at the guage. Thought mine was running low. Kept Turing up the pressure. Finally got a test gauge and my pressure was 35#. Got rid of the isolator and run hot right to the gauge with a snubbed and needle valve.

I'd get a mechanical test gauge. Vulcan sells them. Takes the guess work out if it. If you're running an isolator I'd be really suspect of a proper reading at the guage. Thought mine was running low. Kept Turing up the pressure. Finally got a test gauge and my pressure was 35#. Got rid of the isolator and run hot right to the gauge with a snubbed and needle valve.

 

Interesting...  I am running the isolator actually.  I'll take it out of the picture tonight and see if it makes a difference.  I've read that you shouldn't run diesel directly into the cab, but I've also read that quite a few do it, and have never had any issues..

If you install a needle valve you can shut it off should it become necessary. Use that black air line tube to the cab. Like 300 psi. Isolators in theory are nice, but can lead to accuracy issues. Plus you don't need to worry about bleeding off the air. There is a write up on it somewhere with pictures. The test gauge from vulcan has a 6' hose. You can run it into the cab. I hook I up and take it under the truck and adjust the fuel pressure and get it right where I want it. No jumping up and down to see the gauge. Since dumping my isolator Ive not had any pressure fluctuations. Or appearent fluctuations should I say. I'm at 20psi idle when warm and grid is not cycling on and off.

If you install a needle valve you can shut it off should it become necessary. Use that black air line tube to the cab. Like 300 psi. Isolators in theory are nice, but can lead to accuracy issues. Plus you don't need to worry about bleeding off the air. There is a write up on it somewhere with pictures. The test gauge from vulcan has a 6' hose. You can run it into the cab. I hook I up and take it under the truck and adjust the fuel pressure and get it right where I want it. No jumping up and down to see the gauge. Since dumping my isolator Ive not had any pressure fluctuations. Or appearent fluctuations should I say. I'm at 20psi idle when warm and grid is not cycling on and off.

 

I do have a needle valve installed - so I'm good there.  Is there any danger in running the standard translucent white tubing for awhile until I can find the black stuff?

I ran a cheap oil pressure gauge with copper tubing. Got sick of false gauge readings

I do have a needle valve installed - so I'm good there. Is there any danger in running the standard translucent white tubing for awhile until I can find the black stuff?

Napa has the black stuff, but you'll be fine for a while with the clear stuff. It's just a safe gaurd for the long haul.

Thanks guys!  It ended up being the isolator after all.  It didn't come with any instructions, so I just bled the air on both sides and put it together.  When I started reading up on it I found some instructions about pushing the diaphragm inside back with the eraser end of a pencil after bleeding the air on the fuel side.  I hadn't done that..  so the diaphragm had moved up and was pushed completely against the 'out' port on the fuel pressure gauge side.  

 

I tried to remove the isolator out of the picture completely, but I don't have the correct fittings.  So I took it all apart and re-did it the correct way, and bang..  30+ PSI!  Turned it back down to 19.. checked for leaks.. and then called it an evening.

 

Emailed Pureflow to let them know not to send the replacement pump if they hadn't already..

Excellent. This site has saved my bacon more than once. Glad we could help. If you start having pressure issues again, start with isolator again. Maybe work towards eliminating it when you can get the right fittings. Mine was ok for a while and then started acting up again. No issues since getting rid of it.

I have seen people have more issues running isolators than anything else I think when it came to false gauge readings. I would just eliminate it when you can. I have had my gauge straight plumbed into the cab with just a needle valve. In case of any issue, I can just open the hood and turn the valve off. I just feel like you will get the most accurate readings this way.

I'm using air brake line for my gauge its rated to a burst strength of 600-800 PSI. Copper is risky because 9 times out of 10 the vibration will crack the tubing. Cheap oil pressure tubing (nylon) typically fails from heat and becomes brittle. As for isolators they tend to always skew fuel pressure readings.

 

 

Just as a safety precaution I always check to make sure the airbrake tubing is rated for fuel/oil use. Some is and some isn't. I know the tectran brand of line is not rated for fuel/oil.

i myself would steer away from the raptor pumps. just ordered an airdog 150. i have been through four of the raptor 100gph pump within the last year, really hoping the air dog fp-150 will be a large improvment