Hi, after putting an overflow valve on, checked timing and adjusted the shut down soleniod my truck ran better than it had, and started great. I ve probably driven it 10 miles since then. This morning ( around 30 degrees F) it was terribley hard starting. I cranked for a while, stopped then tried again. It started slow, 1 cylinder at a time. Once running, for a minute or 2 I started driving slowly and very slowly eased on the gas. At around 1800 it crackled, blew white smoke and nearly died. Sounds like an air leak to me. Any thoughts? It has an air dog pump and 1/2 inch fuel lines starting at the suction tube of the tank. Where could it possibly be leaking air???? Thanks

 

Did you check timing or re-set it?

If you reset it, almost sounds like the timing slipped, pretty common for first timers.

 

just checked it, it was perfect

 

You have a problem with air getting into the fuel i saw your prior posts and what you have done before. That is why the long crank to get it fired.

 

Try letting the lift pump run for a while before starting, see if it starts up quicker. Won't help with any air in the injection lines, but should purge the air out of the pump itself.

Is the airdog plumbed in through the stock filter housing?

 

Went back and re-read it myself, did you ever get that fuel pressure gauge on?

You need 25 at idle, 32-35 at WOT

 

Havent gotten the gauge on yet. The air dog goes from tank suction hose through its own filter unit and directly to the injection pump. Im gunna check for leaks. Thanks!

 

Before I went any further, I would verify I had enough pressure.

 

Yea I got my pressure gauge today. Started to instal it but none of the 4 fittings that came with it even fit on the guage itself. Haha thanks alot Jeg's. The hardware store doesnt have the right thing either, gues I ll waite and order it monday from MSC. Also, today while workin on the truck i noticed that with the fuel line disconected from the injection pump, and running into a bucket, there was an air hissing sound. I checked it out and the vent on the very top of the tank was sucking air(normal) but when I shut the pump off it continued to suck air for about 30 seconds. Maybe the pump is moving fuel out of the tank faster than air can go in? maybe causing a suction and starving the engine of fuel? Heck of a theory. Haha Ill post when i get my gauge in.Thanks guys!

 

I'm sure it will only suck air like that because you are not returning the fuel to the tank and the volume of air that has to displace it is large compared to the fuel consumed under normal conditions.

 

Exactly

 

Since you eliminated the stock filter assembly, what did you do for you injector return line?

 

It has the air dog return line. It goes from the injectors to the tank with the supplied 1/2 inch line. It came with a special replacement filler neck that has a fitting for the line to attach. I stand corrected on the reason for the air hiss. Thanks.

 

Also, with an electric fuel pump the pressure should be constant and not change drasticly with engine rpm, unlike a stock cam driven pump. So i gues im going to want around 35 psi all the times?

 

Good question. I've been trying to find that out, but haven't seen anyone say anything about 12v electric pumps.

Are you using an external regulator or does the Airdog self regulate or have a regulator in it?