Subford nailed it, Thanks as I was not aware of that procedure. Note that the output is measured as a frequency, not as a voltage. Something you cannot do with a basic multimeter, hence the tachometer.

Still don't know how you will relate this info to your no start condition. If there is a problem, it would set codes and I never have seen a faulty MAP sensor produce a no start condition.

 

The MAP sensor is not looked at during starting.

 

I'll throw that test out the window then . Good news is I finally got a code out of it. 556, Fuel pump primary circuit failure. That may explain the fuel pump issues in the past. But now, and please bear with my naïveté, how do I fix it.

 

Well I'm heading out in this single digit temperatures to start from the fuel pumps forward checking for power.
The part that's confusing me at this point, before I do the checks, is the fuel pressure issue and the fact it won't start with ether either. I "think" I hear the fuel pumps kick on for a second when the key is turned on, but I get no initial PSI at the rail. When I crank it over the PSI jumps high but no catch.
If anyone has any tidbits for me I'd greatly appreciate it. This working in the driveway at 9* gets old pretty quick. I'll be checking in with what I find. Thanks all.

 

Back in from the cold.
Long story short, I've got 12 volts coming out of the coil and through fuse "U" in the engine compartment and the same to one of the tabs for the fuel pump relay.
But, I've only got 6.5 volts coming out of the fuel pump relay on the DG/Y wire heading to pin 66 on C202 and then subsequently on to the inertia switch an so on.
I'm not really good at anything yet but electrical is definitely my worst so is this just a bad ground? A bad relay (I just replaced it)? Or something else along the line. All your help is greatly appreciated.

 

Well, everything you have posted so far would lead me to believe that you do not have a fuel pump, or electrical problem.

Don't worry about that 5-6 volts coming from the ECU when the engine is not running. That line supplies a ground to the relay with the engine running and a check signal for circuit integrity when it is not running.

There are two things posted that are interesting;

First, 30 to 50 lb fuel pressure is too high. The only way this would happen would be through a restriction in the fuel return line, a faulty fuel pressure regulator, or a faulty measurement. Have you tried another fuel pressure gauge?

Second, you verified you have spark, but it will not even fire with fuel sprayed into the intake. Either the engine has flooded from too much fuel, possibly related to the high fuel pressure reading, or the timing is so far off that the mixture will not light. Possible cause may include a jumped timing chain.

So, I would suggest you first verify those high fuel pressure readings with a second gauge. Next, establish just where your timing is set using a timing light and finally, run a compression test. A jumped timing chain will dramatically change the ignition timing and produce poor compression.

 

Ok so the low voltage isn't an issue? I'm not arguing just asking because all my diagrams show that I should have 12 volts throughout the system and I've got that up to the fuel pump relay but only the 6.5 coming out at the engine compartment panel. All the other wiring coming out of the panel is showing 12 volts where it's supposed to.

 

Also, could it have jumped time all of a sudden like that? I'm again just wondering because this isn't the first time this truck has shown these symptoms. It's run great in the past with the new fuel pumps I've mentioned in the interim but this time the new pump didn't fix the issue.

 

And then again, my book says I should have 35-45 PSI in the rail with the key on engine off. But I don't have anything at all until I crank it over. I unfortunately do not have access to another fuel pressure gauge.

 

It's something that is easy to overthink. Yes, your fuel pump runs on 12 volts and a full 12 volts is applied when the fuel pump relay is energized. This 12 volts does not come directly from the ECM. Think of the relay as a remotely operated switch. The relay contains an electromagnetic coil and a set of contacts. They are electrically isolated from each other. The contacts switch the +12 volts from the battery power distribution to the fuel pump circuit. The coil has two electrical connections. It also operates with 12 volts applied, but it is configured a little differently. One end is connected to an ignition switched source of +12 volts and the ground is applied to the other end from the ECU. The ECU will only apply a ground when the ignition is first turned on, (for 1 second), then it will continue to apply the ground if the engine is turning, (cranking or running). If the engine stops turning, (or fails to start), the ECU removes the ground from the fuel pump relay. This is done for safety reasons. You don't want pressurized fuel spraying around if a fuel line is ruptured in an accident. The ECU does a couple other smart things. It checks the circuits attached to it by sending a coded signal. This signal is typically a low current pulse at the internal operating voltage of the ECU which happens to be 5 volts. Your meter sees this as a steady reading. Entirely normal!

It would not be the first time a timing chain jumped on engine shutdown, but it is entirely a guess on my part. I suspect this because you have spark, but cannot get the engine to fire, even with fuel sprayed into the intake. Check with a timing light and a compression tester and you will know for sure. Don't assume anything!

When your pump runs for that 1 second when you turn the key on, it will be building pressure. Try turning the key on and off several times without cranking the engine. Sometimes you can borrow a fuel pressure gauge from your auto parts store. Commonly quoted pressures are 32 PSI KOEO and 28 PSI KOER.

 

Thank You for that answer. It is very informative and keeping me on the right track.
I'm heading to the parts store shortly to rent a compression gauge and I guess buy a timing light since they don't loan them out unfortunately. I'll see if they have another fuel pressure gauge.

 

You can do a quick and dirty check on the timing by lining up the timing mark on the balancer and popping the distributor cap to see where the rotor is pointing. It should be near #1 or 180 degrees out.

 

Did the quick and dirty on the timing as I haven't been able to get to the parts store as of yet. By eye it looks good, 180*ish out at 0* on the balancer. The wife is at the parts store now actually picking up the compression gauge and timing light for an exact measurement later.
In the meantime I changed out the pressure regulator on the rail. Awful, awful placement. Anyways the old one definitely had something rattling around in it when shaken, whereas the new one does not. Hopeful. KOEO pressure at the rail now reads 34PSI, right in range and prior, with the old regulator, I was getting nothing. Still won't start, dammit.

Rechecked for spark with an HEI spark tester on all cylinders and we're good. So that means my coil, icm and stator/pip are all good right?

 

While she is at the auto parts store have her rent a NOID light set to check the fuel injectors.
If you have good spark then yes they should be OK.

As far as the fuel pressures goes all of the books are wrong on that 45psi for a V-8. The fuel pressure regulator (FPR) has spring in it rated so it will give 39.3psi fuel pressure at zero vacuum. We all say 40psi instead of 39.3psi. All the time the engine runs it must have 39.3psi fuel pressure across the fuel injector. So with the fuel pressure gauge you will get 30-33psi at idle and about 40psi at WOT when throttle is kick open or run it is ran with the vacuum line off the FPR.

You will also get about 40psi if you ground the fuel pump pin in the self-test connector and turn on the key with the engine not running.

 

I had checked the injectors with a NOID originally, only 5-8 though as I didn't want to pull the intake to access 1-4. Is it time to do that?
Also, just checked timing and it looks good. Right about in the 10* range as far as I can tell. I've got the battery back on the charger to retest in awhile but I'm pretty sure its good going off the down and dirty, and now the light test.