I'm having a hard starting issue on my New (to me) 1996 Olds Bravada.

The engine is difficult (sometimes almost impossible) to start after sitting overnight, or after sitting for 6 hours or longer during the day.

Here's the diagnosis and testing that I've done so far:

• Fuel pressure is good after system primes. I'm getting about 55psi after it primes.
• Fuel pressure is good when running, it drops down when you start it and it's idling, but spikes back up if you stab the throttle quickly. It seems to be following intake manifold vacuum/absolute pressure, just like it should
• After sitting overnight, or for 6 hours or longer during the day, fuel pressure drops to zero. It comes right back up when you turn the key and the system primes.

I'm suspecting that the poppet nozzle(s) is/are leaking, causing a flooded condition.

This seems to be further confirmed by my workaround. It will start fine the next morning if I pull the fuel pump relay while it's running, and let it run until it coughs and sputters and dies from no fuel, then turn the key off. The problem only happens if I shut it down with the fuel system pressurized to operating conditions.


I have a stainless steel "ultrasonic jewelry cleaner" that I often use to clean mechanical injectors on old Mercedes Benz and VW's. I was thinking of pulling the intake plenum and putting the poppet nozzles in my ultrasonic cleaner with a mixture of acetone, mineral spirits and "fuel injector cleaner" and letting them soak/clean for an hour or so.

Is this likely to fix the issue? Is there anything else to check while I'm in there. I have a full intake gasket set (upper and lower). I will probably pull the lower manifold at the same time. I've got a broken bolt on the thermostat flange that I need to remove (possibly drill and helicoil)

Are there any other things in this area that are designed to last "the life of the engine" which might need maintenance after 180K miles?