The saga of my Suburban continues!

I left the truck with a friend of mine who's a mechanic and had him take care of some of the issues on it while I was on a long business trip. Now that it has a new pitman and idler arm, as well as the timing properly set and a bunch of other little items, the truck drives fabulously. It's not there yet, there are still some items I have to take care of, but I have a pretty good game plan set out for handling those things.

One issue I currently am trying to tackle is a hard start. The truck does not hold fuel pressure when it is shut off after a few hours. If I go to start it up shortly after shutting off it will start right up and be fine. However if I go to start it in the morning and then leave it sitting all day until I'm done with work, it will have to crank for a while, and then once it catches it will fluctuate in idle a bit as it's bleeding the air out.

What I am wondering is where I should look to solve this problem. The fuel pump is new (which helped running immensely). I have not changed the fuel pressure regulator. Is there a check valve or something else that I should consider looking at?

Thanks!

Fuel filter clogged? I know the pressure bleeds off on my Suburban (5.7l), and when I first turn the key on, I hear the fuel pump run a few seconds and shut off (or go quiet as if it met the pressure demand).

The check valve is in the fuel pump.:o: Depending on what brand of pump you installed,they often leak with many aftermarket pumps.Ive had very bad luck with Carter pumps lately. There are 3 things that will make you lose fuel pressure,check valve,fuel line leaking fuel,or a leaky injector.

You can "bump" the key to prime it before starting,just turn it on and wait 3 seconds,turn it off,and bump it,that will run the pump,priming the lines,then it should fire right up.

The check valve leaking is annoying more than anything else. One last thing you want to check is the fuel pump relay,when they go bad(and they do),they run off the oil pressure switch only.This means the engine needs to crank long enough to close the contacts on the oil press switch,then it starts the pump,by then its been cranking 5-10 seconds.
Find the green single wire connector under the hood,( it should be under the plastic cover on the pass side of the firewall behind and above the distributor,its the fuel pump test wire,put a test light on it,and turn the key to run but dont start it,you should see the light come on for 2-3 seconds then go out.if not,the relay or wiring likely needs help.A bad fuel pump relay will give the same symptoms as a bad check valve.You can run 12V to that green wire as well,and the pump will run as long as you have 12V at it.Good luck...

Well, I can about guarantee that the fuel filter isn't clgoged, because I just changed it (before doing the fuel pump) and it made no difference. I changed the fuel pump, and it didn't make a difference in this behavior, either. This behavior has been constant Come to think of it, I noticed yesterday that I didn't hear the fuel pump turn on when I turned the key to the "on" position, which I found somewhat odd. Meanwhile, right after I changed the pump (when I definitely did the priming technique) I did hear it working. So I will check that relay tonight.

That said, I am fairly certain that there is some sort of pressure leaking. When I removed the TBI unit a few weeks ago, I remember disconnecting the lines and very little fuel came out, on the order of drops. Also, when it's warm it does start much quicker, but then again it's not consistent. It's possible that the relay has worse contacts when it's cold.

The truck still isn't running at 100%, certainly not based on my butt-o-meter, but it's got a good sum of power. With 201k I am fairly certain that the timing chain is stretched at least a bit, and I intend on changing that for good measure. My guess is that my cam timing is somewhat retarded because of this, and that in fixing it I should gain the rest of the low-end torque that I believe this engine should have but doesn't.

Faulty fuel pressure regulator? Is it a TBI or a TPI?

It's a TBI. I have thought about just changing the pressure regulator, but I am wondering if I would be better off just changing out the whole throttle body assembly, seeing as it has 203k on it. What are your thoughts?