Okay, here's the story so far...
Car was running fine until after a really heavy rain (car was parked during the storm,) last May when I started it up and it ran really rough at idle (smoothed out above 2500 rpm,) Then it just died and wouldn't start. The next day, I was given an out of town work assignment for 6+ months, and didn't return home until just before Christmas.
I've been trying to get it to start, to no avail. If I use some starting fluid, it will fire up, but immediately dies. I've put in a new fuel pump, new fuel filter (the old filter was pretty clogged up,) and new pressure regulator.
When I relieve the shrader valve, just a little fuel comes out, without much pressure.
Any suggestions???

 

maybe a small amount of water in a fuel line turned to rust, and plugged the line?

Have you listened for pump operation?

 

test your fuel pressure with a gage

 

Okay, today I checked the fuel pump, and it is working. Took the fuel lines loose from the engine and pump/tank and blew them out, and blew out the fuel rails also. Gas in the lines, and in the tank, may be contaminated, or degraded, as it appeared slightly white-ish. Same with the fuel in the fuel rails. After blowing the lines out, the fuel coming out of the shrader valve appeared clean. 30 PSI at the valve. Still, no start.
Tomorrow, I'll put in some new spark plugs, clean the injectors, and drain the tank (if the other steps don't work.)
When this all started, the car did throw three codes with the OBD 171, 174 (lean right and left bank,) and 300 (random multiple misfires.)
Once I get it to start, I can sort out the other problems that will surely arise.
I love my vette, but all I'm thinking right now is, "I really miss my 67 SS396

 

If the drain by the fuel fill is clogged then water would have entered the tank. If it was parked outside while you were gone that would be a strong possibility.

 

Few suggestions.
Fuel pressure does not guarantee fuel flow. Pull off the return line at the tank and run the pump and see if fuel is returning to the tank.

Just to make sure, check the drive to the injectors with a noid light while the engine cranks.

When cranking, fuel pressure should remain 30 or better and above 35 is pretty normal.

Make sure there is a good spark, 1/2 inch ark is normal.

 

You should have more than 30 psi of fuel pressure at the rail. My 93 has 42psi keying it up to ON without the engine running. Stock all the way.
Has 38 at idle.

Getting water into C4 gas tanks is somewhat common, check the drain hole in the filler neck area is clear. Adding another one is a good idea, they are a known issue.

If you suspect water in the fuel, drain the tank and get as much out as you can.

Also, what kind of fuel pump did you put in?
I've had issues with parts store pumps not up to par. (Granted it was on a turbo car, the 1 yr old. new pump deadheaded would only put out 50psi. The car required about 52+ at WOT under boost. A Walbro fixed that lean, detonation problem. The Walbro deadheaded made 80psi.)

 

Definitely check for water in the fuel as suggested above. I also agree on the pressure -- you should have 42-45 PSI. 30 should be plenty for it to start though.

 

You said fuel filter was pretty plugged up....which filter was that? I hope the one on the frame under the passenger seat......The "sock" in the tank don;t count..

Cleaning the injectors...pointless.

They have baskets inside the inlet side of the injector. If those screens are plugged, they have to be pulled out, ultrasonically cleaned and reassembled. Hardly worth doing to the stock injector. Replace. not a repair item.

Have you pulled plugs to see whats inside? A wet plug most likely. This is an Opti-Issue. Just because starting fluid gets a burp...does not mean the Opti is good. BTW...that starting fluid will kill your engine and aluminum pistons...

The engine should start at 30psi. Whats the pressure hold test? The system should hold pressure for several hours.

Do this with the fuel pressure gauge connected...
Key ON....watch gauge and note pressure from key on... approx 30 psi for now.
D/C the fuel pump fuse or unplug the pump. Crank the engine and watch trhe gauge. As the engine cranks the gauge should drop downward with every revolution. Thats the inj firing and bleeding off the static pressure until there is none.

IF this happens the way I describe, go buy a new Opti Spark.

IF the fuel pressure holds and does not drop ANY...no movement of the gauge when cranking, then that indicates that the inj are NOT delivering fuel to the cyl for whatever reason.; either no inj signal OR the inj are plugged up (unlikely, too much filtration to happen easily).

Go back and start verifying the spark. The Opti dies from wet. First time it sees water it dies. They are sensitive and when they fail it can be in the timing dept, or the spark intensity, or the irregular signal to generate spark. It dies in many ways and gives odd symptoms everytime.

Follow the FSM flow charts to diagnose.

 

What I've done so far... Blew out all fuel lines and reattached.
Fuel pressure is 42 PSI (first gauge I used was defective,) fresh fuel, new Airtex fuel pump, new screen, new inline filter, new pressure regulator, new pump relay. New Bosch Platinum plugs... old plugs were worn and dry. Noid lights show signal to all injectors.

Hence - dry plugs w/excellent spark, and signals to the injectors means there is no fuel reaching the cylinders due to severely clogged or plugged injectors

Solution??? - I ordered a new set of Bosch 3 flow matched injectors for the LT4 from FIC, and will install them when they arrive this week.

Outcome - TBD

 

HI.Take that after market pump out.30 not enough.GM delfi good choice.You said car got wet.Hows the opti miss distributor.Hall efect controls spark and sequential injection.Have a good tech look at it.