Ok so here it goes. I installed an Air Dog II fuel system. Altered the in tank lift pump like instructed. Truck would start and run fine until it would get near half a tank and it would start sucking air and acting erratic. Simple fix keep it above half a tank. But i wanted to fix this issue completely so i ordered a pre-made draw straw fuel module from Vulcan Performance. Installed the fuel module with no problems. Truck fired right up no problems. The next day truck fired right up again no problems. Later that evening it seemed as if it lost prime, it took atleast 5 minutes to get the truck fired up. Then again later it took atleast 15 minutes to fire and seemingly has been getting worse. I have no codes. I've verified i'm getting plenty of fuel to the injection pump by removing the line and turning the key on. I've also broken lines free at the injectors and made sure i'm getting there while cranking. This is where i'm stumped and considering it being a electronical issue because i had 4 injectors primed and still the truck wouldn't start. I'm leaning towards a possible crank sensor but i didn't look to see if its registering RPM when cranking, tomorrows project. But if anyone has any input at all it would be appriciated. Thanks ALOT for your time.

 

Is the pump running as soon as you turn the key on, and while cranking?

 

Yes sir. I was told to wire the pump directly to the engine fuse due to it not running properly when I had it plugged into the old lift pump harness. It never had problems with it before because I know I've read a lot saying vp pumps "don't like fuel when tryin to start."

 

That's exactly where I was going with my question. That could be your hard start problem. You may need a toggle switch, or put the ADII onto a power supply that cuts out during cranking.

 

My only question with that is why would it of started fine prior to installing this new fuel module and now it not? I've had it hotwired the whole time it's been on my truck (7 months maybe). I mean it would be something to try but it just doesnt make sense. I just figured it would have been a problem this whole time if that was the case?

 

Something else to try;

When you first go to start the truck, let the pump run without starting. Listen to the pump and try to hear for a change in sound. If it goes from pumping fast and easy, then sounds like a load is added and bogs down a little, you could have fuel leaking back.

 

Yea I'll have to check that but the thing is if it's gettin fuel to the injectors, I cracked 4 line, and has fuel comming out of them the truck should fire. I mean it might take off rough but it should technically fire. That's the only reason i'm starting to wonder if this is something different than a fuel issue.

 

You may be correct thinking crank sensor. Have you been able to see if it registers RPM while cranking yet?

 

It does register RPM's (around 100 when cranking and approx 200 when it seems like it is wanting to fire). I'm not sure what is normal but it seems that that's probably relatively close.

 

OK, I have an 02 and this is my first Cummins. I'm not real knowledgeable on diesels, but a pretty good mechanic. My wife is trying to get me to quit cussin', but this darn thing is hard to start! Morning, 3 15-20 seconds cranks. Warm after it sits 30 minutes, 2 12-15 seconds cranks. I did some reading about about the fuel return line (is is stock with 112K miles by the way) and I think it may be leaking. I tightened up the fitting on the T, but I think it might be leaking where the plastic line attaches to the metal line. How does that connection work?? Is it an o-ring? How do you get it apart? The banjo bolt on the back of the head seems dry, so I really don't think it's leaking. Any help is appreciated!!