cpz28

A little background on the car (in signature): I'd let it sit outside for 5-ish years (no real good excuse), when I went to start it, it wouldn't start and I didn't hear a fuel pump prime. It would kick over if I sprayed ether into the intake. So I replaced the fuel pump, and it works (Racetronix kit). I drained all the old gas up to the fuel rails, and dumped some fresh premium in the tank. Then, the car still wouldn't start, and then I saw I had no spark. I changed the coil, because it's cheap, nothing. I've checked all the wiring and grounds.

So I ran all of shoeboxes diagnostics and determined the opti was the problem. I just swapped in a new one (bench tested to be functioning, Mitsubishi optical sensor). I have now have spark, so there is progress. But the car still won't start. I'm sure the opti is installed properly, because the spline drive can only go on one way. I double checked all the wires, they are on the proper terminals. I had the ICM tested at O'Reilly's and it was fine (it was replaced with a GM unit 10-ish years ago). I don't have a security light or SES light on. The injectors have 12 volts and are pulsing. And now the car won't start when I spray ether into the intake.

I'm stuck. Thanks in advance.



Thanks. I appreciate your guys' feedback in advance.

Injuneer

cpz28

I'm not sure I hear popping, I don't really smell fuel after trying to start it (with the intake elbow off). I didn't test the pressure, but when I disconnected a line to purge all the old gas, there was plenty of pressure.

This weekend, I'll pull the rails up and see if the injectors are spraying or not. Good suggestion, thank you.

As for the opti spline, I was careful to put it back in the same orientation as it came out and that was also the only way it went in. I quadruple checked it, having heard the cringe worthy tales of people having to pull everything back apart to check. Even so, I was thinking that GM should've made the spline shaped like a "D" just to eliminate any chance of installing it wrong. But I guess if we're talking about things GM should've done when engineering the optispark, the list goes on and on.

cpz28

Update: The car now runs. It's been in my parents' garage, and this weekend, without me, my dad pulled the fuel rails, fuel pressure regulator and and injectors. He said he cleaned everything and put it back together, and it still wouldn't start. I might not be regurgitating this right, but then sucked air through a hose that's connected to the vacuum diaphragm that controls the fuel pressure regulator and clamped it off. This opened up the gas flow and it took a bit for the rails to prime, but now it's starting/running fine.

So now I pretty much just have to change the oil, replace my bald Nittos and enjoy the car again.

Injuneer

If the vacuum compensation line is no longer connected to the fuel pressure regulator and to the intake manifold, it needs to be reconnected. The purpose of the vacuum line is to control fuel rail pressure so the DIFFERENTIAL pressure across the injectors is held constant at 43.5 PSI. That means when there is high vacuum in the intake manifold, the rail pressure has to be reduced to maintain the DIFFERENTIAL pressure. If the car will only run without that line, and with some sort of vacuum in the clamped off vacuum line, the fuel pressure regulator may need to be replaced as well.