That's true.....

So if;

- Fuel Pump delivers bulk and instant fuel pressure - pump seems to be working fine.....probably no split fuel line, blocked fuel filter, etc....

- Starting instantly on Ether can be taken to signal NO flooded condition....

Then......where could the fuel be so rapidly escaping to (without creating a rich condition)??

Back to the tank via the return fuel line???
Then what could allow this? Just the Fuel Pressure Regulator?

And......what happens after the Ether gets the engine running?
Fuel Pump supply ongoing is enough to overcome the 'leak back' to fuel tank?
Maybe a PO put in a bigger flow fuel pump to overcompensate??

 

I still think your first thing and easiest ,is to check if fuel is just coming back to the tank through the regulator (return line)

 

Absolutely!

Many Thanks!

 

Red has the next steps right.


1. prime system and as soon as the pump stops have a helper clamp the return line AND the sending line (look that up) Vice grip with a rag works. pressure behavior now tells you something. You can remove the vac supply line from the fpr and if it doesn’t smell like gas then the diaphragm is not ruptured. This would point to either an external leak, or, injectors leaking. (common). If pressure holds with both send and return clamped, then its probably the sending unit. I *think* there is a one way valve in there??? Release the sending clamp first…..leakback through sending u it?

2. if its the injectors, john bannerman at fuel injector connection is the guy i use. i like bosch 3.

 

OK Folks.......prepare the Champagne!!

I clamped the return line.......no difference.

That points to fuel pump check valve......

Now.......remembering that I'm in Australia, less than 5 mile from a field with kangaroos in it........Popping down to Jegs for a replacement fuel pump for an 87 Vette just aint happening.
Besides - I wanted a proof-of-concept before I go opening the fuel tank 3 days before Christmas, etc.......

So, I went down to the local speed shop and got them to collect me up parts for an in hose check valve, and pressure gauge.
Mounting the fuel pressure gauge on the engine side of the check valve allows it to read the pressure in the system right through to the fuel rails.

I celebrated this with a quick stop at a brand new store here......it's called Taco Bell.......not particularly great, but did what it was supposed to do.....

10 minutes of installation later;

 

And then I fired the pump to prime.
Pressure went straight to 55 psi.
Turned the key off.

.......drum roll please.......

Pressure did not budge!!!!!

Did I dare to try to start it without any ether???

It started straight up.
Turned it off again.
Pressure didn't budge.
Started straight up again.
I cried just a little.........

I left it turned off for as long as I could handle.......approx 60 seconds.....
Pressure hadn't moved.
Started straight up.......like a normal car........no tap dancing or indigenous tribal throat singing required.....

 

So I'd like to start by thanking my parents, my school teachers, the first responders, my uncle George, and all of the other good people of the world.

I should probably give a big thanks to all of the unknown souls that left all of those posts on various forums and youtube clips over the millenia for us to glance back over....some of them are even correct.

Most of all......thank you so much to all of the wonderful folks on this forum for their kind, polite, patient, HELPFUL input and inferred encouragement that is helping people like me to live out our 80's Corvette driving dreams in way-off places around this big old globe!

 

Remember that there is a pulse damper between the pump outlet and the hanger that could be your source of bleed down. For testing, you can replace it with an equivalent piece of appropriate fuel line (that will survive inside the environment of the tank). Many just delete the damper.

 

creative way to test. i like.

 

OK.

The morning after......

System still loses all pressure in less than an hour, so something is not as designed.....but.......pressure IS held after initial prime, so car starts......

I'll take that as a major WIN!

Now I can see if I actually have a VATS (or other) based non-crank issue......and/or a parasitic draw flattening the battery.....

"Live report @ 11".......

 

Only possible to get creative/constructive like that in response to increasing understanding of what the stock system is trying to do, so once again.....a large thank you to all here, and on other forums/youtubes that have generously provided so much information to allow so much understanding!

 

leaking down in an hour is fine. “ no worries “about that. you may have a leaky injector but thats a very slow leak. ive never had a c4 that didnt leak down. your case was extreme and its the second one ive seen on the forum like that.

As mentiomed you may have a split or torn or split component of plumbing at the pickup. I dont think it would be too tough to order a replacement kit even if u are in the outback. 👍

 

Don't get me wrong......I'm 30 kms East of Melbourne.......but there is still native land around here with native kangaroos......
We have speed shops, etc......they just don't cater much to specific American cars that were never sold here.

I just checked again.......12 hours after the last start, it's still got 25 Psi pressure. Very happy.
Just about brave enough to take it down to the cafe for brekky!

Did it start? No....battery is flat again.....so I guess next I'm chasing down a parasitic draw. A new starter and power cable to the starter can't hurt either....

NB - car was converted to RHD in approx. 1992.
It looks like they mostly just used the stock wiring loom, but moved stuff around and mounted modules to wherever the wiring would allow them to stretch bits to.
For Example;
The ECM is mounted in the centre behind the DIC back against the firewall, with wiring going off to the right.
The "central" fuses are on the right hand side, above where your left knee would be sitting in the American passenger seat (our Driver's seat).
The OBD port is forward from those fuses....

I need to remove the locally installed Immobiliser (alarm system), since it does nothing, is wired with spaghetti, and is a bunch of intermittent issues just waiting to happen....
In all of my hunting.....there does NOT seem to be a Starter Enable Relay anywhere......possibly what is currently running through the immobiliser......
Odd, since I originally thought my non-crank non-start issues were due to VATS kicking in. (Key Pellett seems to work fine).

My plan is to note down the number of wires and colours of the wires in the loom bundles that the immobiliser is wired into, then throw myself on the mercy of the forum crew here!!