Need some assistance from the experts,

OK ... I have read probably a hundred posts on the lift pump and testing and I am still not sure I understand everything yet.

I tested the pressure on my 99 at the two plugs on the filter housing. I wasn't able to come up with the Shrader valves that they tell you to put in place of the plugs but instead connected the gauge directly. Since the truck is in a no-start condition, the best I could do was to check pressures with the key on and the lift pump running. This gave me about 10 lbs at each port. When I tried to start the engine (with gage attached) the pressure dropped to zero.
Now ... are the Shrader valves really necessary for this test and can I assume that from the drop in pressure that the injector pump is sucking fuel faster than the lift pump is providing it ?

I cracked #1 and 3 injectors and have fuel ... still no start. I want to fix it but I am not sure that I am 100% sure that a new lift pump is the cure. The more I thinks ... the confuseder I gets.

PISTOL

 

The lift pump doesn't run while the engine is cranking. If it did, it would cause a hard start condition because the extra fuel would mess with the timing a little. Bump the starter, but don't start the truck, and see what the pump is putting out. It should cycle for about 20 sec doing it that way. The schrader valve is only put in when you run the gauge into the cab so you can dampen the pulses from the VP and stop your gauge from bouncing all over the place.

 

Blue,
That is what I did ... sort of. I didn't actually engage the starter but the L/P was on and building pressure. This gave me a reading of 10 lbs which it held steady.

When I shut off the key, the L/P runs for about 25 - 30 seconds.

I noticed no pulsing of the needle when I cranked it. Would this only happen when it is running ? The theory makes sense to me ...

PISTOL

 

On older 2001 and earlier the lift pump runs when you turn the key on without bumping the starter. Thats how mine was until I had a reflash then it changed to the 2-3 second burst on key on.

 

PistolWhipt
The testports your using on top of the filter housing are the right ones.
10 psi at prime is low but you should have enough to fire and idle.
With a VP thats supplying fuel to the injectors she should run.
First, when did the no start come about, after you opened the test ports for the gauge install? If so you may need to do some cranking with the lines cracked to get her running( this would be the cheapest)
Second, Is the VP supplying enough fuel or is it just trickling out of the injector lines? Two things here timing (VP electronics) or not enough fuel suply for combustion. Either way thats a new VP. No mater at 10 psi I would say your LP needs changing. Good luck and keep us up to date.

 

The truck was running fine until I pulled into a parking lot where she just died and wouldn't start. I came back the next morning and after a few cranks, it started and ran fine until the next time I tried to start it.

I haven't been able to get it started since then though. The batteries are needing recharged now as well.

I will go ahead and buy the L/P and see if that makes a difference. We'll see

PISTOL

 

when you went to restart in the lot was the engine warm???????? if so sounds like the i/p went and took the big nap...........

 

Yes it was warm ...

Oh ... I don't like the sound of that. What do I need to do to check the injector pump for correct pressure ? I did get spray but maybe not 4k lbs worth.

PISTOL