so let me begin with this, this all started when i decided to install some DAP 75hp injectors, ( im pretty sure anyway) so awhile back, i posted something about my fuel filter canister leaking which was creating a fuel/air leak, i would surge at first startup. I replaced the canister, all seemed good since then, but i haven't really drove it that much since replacing it, ( I also after i installed the injectors the first time( wrong, i did it backwards and realized it after i got done talking to Mike,) went back through a second time and checked all the o-rings on the injectors, o-rings and crossover tubs, all checked out. still did the same thing after i put it all back together. so then i dug into all fuel lines, From the raptor pump up to the injectors, one was slightly lose but nothing bad!! i was thinking yes!!! and then again no!! same thing, surge after startup.)  so from then to now, this is where i am at.

 

I just got back from my honeymoon last night, about 1 in the morning, tired, cold and grumpy, i left my diesel at my wife's parents house so they could watch it. we were gone for 12 days!!!

I go to start it up after we get to it, nothing....... just cranks..... you have to be f******** kiding me! 1am in the freaking morning!!! with rain!!! Fuel PSI 18* everything checks out, crack the injectors line...... wait a little while..... sputters up.... closed the lines and is all good now......

 

So where the hell could i be getting air from?? the only things that leads me to believe that could be wrong is the injectors?? or the raptor pump?? im lost in my own ideas because i have been through everything x3 now and still cant figure it out! should i send the injectors back to DAP to get the, checked out??

Sorry about the rant, 

Thanks nate!

 

 

How is your return line tee and the return fitting on the back of the head? Simple thing but these cause a lot of hard start issues. There are other culprits but these are simple to fix.

Yea I'm with @dripley on this one. If you've checked what was recently changed enough to verify that's good, move on to other culprits. I think when doing something as drastic to the fuel system as changing injectors, it could cause something else to dislodge or come loose that otherwise wouldn't of everything was left alone. 

 

I'd checked the those two areas on the fuel lines and see if that doesn't fix it. If not then at least you can move down the fuel system and keep trouble shooting.

thats the one thing i didnt even think about checking, ill giver er a shot and see whats happens

If you got a Airdog or Raptor you might have a leaking quick connect fitting. Might have to talk to Eric at Vulcan to get the fittings for Parker Push Loc fitting and convert over to stop the prime loss.

I do have the raptor Mike, I remember you telling me to put grease on the inside of the quick connects because of how much my fuel psi will drop. I did try it, and it didn't seem to have any affect on it. Or any affect on surging.  I'm tearing into it all again this weekend, and using the 12 valve fir a DD for awhile 

Loss of prime is a air leak issue. Like Hex0rz truck his was a injector problem. After changing the injectors the problem went away. So it could be a injector not sealing properly. Return line leak, drawing air in. It could be a supply line problem where its drawing air in on the suction side and draining the line out causing it to push an air bubble to the VP44.

21 hours ago, fuze24v said:

I do have the raptor Mike, I remember you telling me to put grease on the inside of the quick connects because of how much my fuel psi will drop. I did try it, and it didn't seem to have any affect on it. Or any affect on surging.  I'm tearing into it all again this weekend, and using the 12 valve fir a DD for awhile 

Did the Raptor come with its own fuel line and quick disconnects?

Just now, dripley said:

Did the Raptor come with its own fuel line and quick disconnects?

 

Yes. i bought it as the big line kit. i didnt do any modifying to the long hose. just hooked it up and zip tied the hose to make sure it wouldn't rub anything when vibrating 

Get under the hood with a flash light and look for any fitting that looks damp.  I recently had a hard start issue and I finally found that my needle valve was to blame.  The nut on top of the valve was weeping just a tad, enough to make it lose prime.  It doesn't take too much.

I'm not impressed with the quick connections on the AirDog / Raptor series at all. Lots of issues with sealing and air leak issues. Most of the time its resolved with using Parker Push Loc JIC fittings and resolves most of the air issues. The other rare Raptor issue is the pump seal gives up and it starts leaking fuel into the pump motor or air leak that drains the pump out.

Edited October 17, 20168 yr by Mopar1973Man

I have seen a lot of folks having issues as Mike describes. Boogles my mind as to why I have not had them. I did pick up an intermittent miss on hard throttle a while back but it just went away over 3 or 4 weeks. Do not know why it occurred or why it stopped. 

i have natta lol, clean and dry as a whistle! (fuel lines anyway haha) 

 

5 hours ago, Mopar1973Man said:

I'm not impressed with the quick connections on the AirDog / Raptor series at all. Lots of issues with sealing and air leak issues. Most of the time its resolved with using Parker Push Loc JIC fittings and resolves most of the air issues. The other rare Raptor issue is the pump seal gives up and it starts leaking fuel into the pump motor or air leak that drains the pump out.

i am half tempted to throw the old stock lift pump on with the orignal fuel and banjo bolts and see if that makes a diffrenece, or swapping out my raptor, i have another one from a buddy when he sold his pickup.

Just now, dripley said:

I have seen a lot of folks having issues as Mike describes. Boogles my mind as to why I have not had them. I did pick up an intermittent miss on hard throttle a while back but it just went away over 3 or 4 weeks. Do not know why it occurred or why it stopped. 

when did you buy yours? before they cam out with the different design?

My ADII 165 is 6 years old and came with the connectors. I know folks have had problems but dont know what the frequency is.

Remember suction leaks do not leak outwards. They leak inwards so never will you see a wet fuel line or fuel leaking out. Like the suction lines on the Raptor will never be wet but still leak air in while your driving or while you are parked. Air molecule is smaller than a fuel molecule so easier for air to leak in than fuel leak out. 

 

Another way it to run the truck to ensure the fuel lines are loaded with fuel quickly pressurize the fuel tank by using compressed air blow gun and rag at the filler neck. Have a buddy look the fuel lines over and see if the pressure is pushing fuel out any fittings. You might have to use baby powder to see small leaks.