duster75

O.K i searched this and found alot of 12V info. but none really on V.P so can you strech the spring out on these things or get a heavier rated spring? It seems that my earlier posted issue (Airdog pumping air) has to do with spring colapsing and not holding pressure at V.P!!! ???? Anyone else experience this? My A.D 100 is only running 17#s on idle and 14 wot. these pressures are at intake side of V.P Nate

tanderson2002us

I have a Holley with a Moroso spring.......20 at Idle and 18 WOT.

duster75

Is the spring mounted in vp return port/ overflow valve or in your holley? I spotted a prev. post of yours seaching today......Thanks, Nate

Dinner

What is your question here? Are you wanting to up your fuel pressure?

If you are wanting to get higher pressures you will have to change the spring in the return port of the Airdog itself. There is a check valve on the VP44's return line, but you don't need to touch that for pressure increase.

nickg

17 at idle and 14wot is normal (almost the same as mine) why do you need more??? if you call pureflow I'm sure they will send you a stronger spring so that you get the psi you want, stretching a spring is a poor way of increasing fuel pressure.

If you need help diagnoising AD issues the Tech guys at pureflow are more than helpful!!

duster75

Guys I'm not looking for more pressure. The tech's at pur flow thought that the bypasss might be my problem .I have to bleed off air in system EVERY time I start truck.Truck ran great for 700miles now I'm suck'in air or possible fuel is draining back to tank after shut down causing me to suspect bypass. thanks,Nate

*********See my other post AirDog sucking Air?************

Dinner

In that case. The check valve threads into the VP44 through the return line. If you look at the two lines that are hooked into the side of the VP, one will be your feed line from the AirDog. The other is the return line (runs along the block for a bit and is steel). The check valve is the Banjo Bolt that connects the return line to the VP44.

I would also recommend checking your cross over tube o-rings and injector line nuts to make sure they are torqued properly.

duster75

Yeah, I pulled it out and cleaned it but it was good.Thing is I hear that it is rated for 7-10 psi (the spring) and I'm running 17-14psi thats why I was asking if anyone changed it out to a higher rated one if they even exist.I know they do for 12v or so I have read here.Thing is I installed A-DOG and I'm on my 3rd tank of fuel and now having problems. Thats why I don't think its the seals unless increase in pressure caused it. But that would be nill because v.p is setting pressure to injectors correct? thanks,Nate

PaulDaisy

The check valve is supposed to be set at 14 psi per FSM with some latitude. It will not serve as a pressure relief though, all it is meant to do is open at 14 psi. You can have greater pressure before it, as it can not flow enough to serve as a pressure relief.
I recall hearing from others that when the check valve is worn it can leak slowly and lose prime. I think they are available separately and are inexpensive.

nickg

just for fun leave the fuel cap loose or park with the nose down hill, if it starts fine after doing either of these two things they for certain you have air leaking into the system somewher OR the fuel cap is faulty and the vacuum in the tank, is pulling the fuel out of the vp/filters after the truck is shut off

rage_blue

Just to add to the stuff nickg jsut posted There is also a valve built into the sending unit on your tank, some sort of vaccume or pressure relief valve. I had air getting into my system and i tryed everything new return valve, new seals on injectors and tubes, new sealing washers on the return line banjo at the back of the head, new feul cap. Finally i pressureized the tank and found that valve leaking. The valve has a nipple on it so I caped it off and haven't had any issuses all summer. So you've got a few things to check out.

duster75

put vulcan drawstraw1 in yesterday.... primed it to v.p started went for a ride noticed rpm's fluctuating between 7-800 when u push clutch in. Trys to die when you leave a stop sign in 2nd.Lack of better judgement I stopped at store to get some beer.Got back out to truck and no start.Bleed injectors #1 weak stream #3 good stream no start.Happens that a buddy of mine shows up and we go get my other truck to pull it home.I hook up and tell him try and pop start it...... it starts... trys to die at stop sign pops it again get it home nothing.No codes..... starting to think I've got elct. issues now. Any ideas???? Thanks, Nate

Krob

Im confused at what is wrong but i would check all the simple things that people have suggested. Parking down hill over night and then leaving the fuel cap off. Those two are free.

Then i would check your preasure make sure you have preasure at the VP. Then check your line...collapsing fuel line maybe, or some kind of leak.

After that i am out of simple stupid ideas.

Hope it helps
Rob

duster75

rag blue http://www.dodgeram.org/tech/dsl/ISB/low_power.htm check this out it has to do with the vent you plugged off

Krob , new A-dog100 installed drawstraw 1/2" lines ect. truck after 2 tanks of fuel has devolped a losing prime issue. Doesn't matter if after you get it started you shut it off it won't start again...used to start after bleeding inj. lines now it wont't even start that way.I will try above suggestions just happen to have a hill for a driveway. thank,Nate

Mike Holmen

You run the stock fuel filter? What you using for fuel lines? Have you checked the injector lines for leaks at the VP and connector tubes?

Is the fuel tank pressuring up? I've been thru these issues, the latest one was that my line coming off the supply side of the VP was leaking enough to cause air to get inside. I had one time, I forgot to tighten down my injector retainer, and caused my fuel tank to pressurize. I had a roll over valve plug-up with junk from gravel roads. O-rings leaking is another common issue. Maybe discribe you fuel system set-up in more detail. VP pumps are sensitive to air leaks. P pumps have tons of fuel, so they can live with a few leaks.