Hello, I'm trying to chase down a problem with my 91 Z-28 not starting.
The car just cranks and cranks and cranks with no start-up.
The fuel pump turns on and pressurizes the lines to 45 psi at the fuel rail. Fuel pressure holds pretty well (still at 40 psi after 30 minutes). The car will start right up immediately if I spray starter fluid in the plenum (but then cuts right back off after it's burned off). All the fuses under the dash in the fuse block are good. All the fuel injectors measure about 12.3 ohms +/- 0.1 ohm. The oil pressure gage on the dash steadily build up to high after a few seconds as I crank the system.
I think the next thing I need to check is the injector pulse, but am kinda confused as to how to go about that. Anyone have any other ideas as to what it could be and what I need to be checking/why the car is protesting lol?

 

It won’t run long on starter fluid.

Like it fires when only in crank position?

 

Only fires with starter fluid and turning the ignition to the crank position, yeah. Otherwise, the starter just turns the motor until I get tired of hearing it not start lol.

 

I just went to O'Reilly and bought a new fuel pump relay, not sure if that is going to help anything but it was fairly cheap. I think i found a video on how to check the injector pulse... Will see about checking that as well here shortly and will post back in a bit.

 

So both banks had injector pulse and the new fuel relay didn't do anything... put the old relay back on and cranked it about another dozen times and it started up and runs smoothly. I'm at a an even greater loss as to what the heck happened now. But at least she's up and running for now. I have no idea. I'll post again with any other weird updates.
Maybe I scared some gremlins away...

 

If it fires in the crank position, and won’t fire in the run position, it is likely an issue with the ignition switch itself.

South Main Auto Repair has a video on their YouTube channel.

Think it was an S15.