Ok, to clarify and a lil history.

Had issues with electrical. Changed key switch, terminal connections. Ended up being power to kill switch was pulling out of the molex plug. Fixed that... Ran fine!!

Today, ran fine out to lake.. 30 min idle and 20 min run.

Did fine, went to leave and cranked off then died.

Thought it was vapor lock, but filter had fuel and even filled it up with P motor just to check.

Idled home. Check fuel pressure at key on and has 38 and can hear pump priming up.

Must be electrical... Key turn to on and buzz sounds off...

What else can kill my ignition like this?? Has to be simple. 454 mag mpi with 80 hours.
Any info I am leaving out/

Cranks over, spins fine, just will not fire off!!

3 fuses in black box with ecm are good.
Will get spark tester tomorrow..

??

First thing is to check for spark.

Just because there is fuel in the water sep filter does not mean its not vapor lock.
The fuel rail could be full of air/vapor.

Thanks griff, I do have 38psi at rail. Gauged at shrader on rail. I will check for spark next, picking up a tool this am.

UPDATE:
Sprayed starting fluid just to rule that out.. Nothing
Checked fuel pressure again on shraeder valve on rail.. 38psi (stock rating)

Put spark tester on ignition wire. FIRE there!

--> Put spark tester on plug wires ( did 2) NO fired!! (Had plug tester just out of distributor,Not on plug side of wire..FYI)

So I had just changed coil, distributor, and rotor in fall.... Barring malfunction of cap and rotor.. What else it in there that would kill fire??

[ATTACH=CONFIG]555635[/ATTACH]

Igition module? How to do test that?

Coil in distributor? How do I that too?

I will do some reading, but any info would be appreciated!

Did this run after you changed all the parts ? Or did you change them after putting boat away and now it doesn't run ?

I changed parts chasing wot issue before putting up. Ran great after changing AND I found that all vacuum lines were loose and falling off. Ran several times after.

Ran several times this spring, though I was chasing another gremlin that ended up being a loose ignition wire in the molex connection behind the dash. (Pin was pulling out) So I had intermittent loss of initial turn key buzzer, which would kill ignition.

SUnday ran awesome from start up to where we anchored and then cranked up after and writhin a min, quit and wouldn't start up.

Also, test lighted the 2 wires going into ignition module and have power with key on..
Cap and rotor still look good.

Bad pick up module inside distributor would be my best guess.

Here you go:
http://easyautodiagnostics.com/gm/4....ed-icm-tests-1

And please, if you need replacement parts, please do yourself a favor and get GM AcDelco parts. We can help you find those, when you figure out the issue.

Thanks, that link is awesome!!

I ran through the different tests, but confused by 1 part.

I do have spark coming from Coil lead, but not have spark coming from several plug wires (but, I only checked 2 or 3).

With no spark coming from the cap, it says that its only when "some" of them do not fire it is the cap. However, if the pick up sensor (coil in dist) is sending signal to module, which is in turn sending on/off to Coil, AND I have spark comig from Coil....

Then I should be loosing spark via the cap and/or Rotor. I guess the part that confuses me is that supposedly checking the cap Test is when some of the plugs don't fire and not all?

I have a dealer down the street from me where I can get a new cap and rotor, or should I still get an ACDelco?? if so, do you know the cross reference? 98 454 mag mpi gen VI.. link http://www.mercruiserparts.com/bam/s.../31812/4854/70

Found the module D1965a, but now that I am looking for cap/rotor.. What is ac delco number? thanks!!!