It started cutting out on Saturday and died at stop light. Had it towed home, tried to start it right before tow and it would not, however it did start about an hour after that. Total time between stop light and starting was about 3 hours. Sunday morning I started it up and it ran for about an hour before it died. Monday, today, it ran for about an hour before it died. I changed ICM for good measure, spark was a little on the weak side, but no change. About 2 hours after it died I was able to get it to start briefly by pumping the throttle about 15 times while cranking and then letting off on the throttle. I was able to get the RPM up to around 3000 and it ran OK for a minute then starting cutting out and died. I was not able to get it started again.

I have narrowed it down to the fuel system, as it starts when I spray in ether. Fuel pressure is 62psi when cranking or fuel pump ON. When fule pump is off the pressure drops to 40psi right away and then drops to 20psi within 10 minutes. I have relieved the pressure to 10psi and it holds steady. The passenger plenum is not clean and is exactly the same condition as the driver plenum. Spider was changed about 60,000 miles ago. Fuel filter is brand new, changed it after problem started.

It seems like the fuel pump to me but some threads I read lean me towards the FPR.

What do you guys think?

Edit: I just checked the pressure and found that it is now only holding at 4psi down from 10psi over the last hour.

Edit2: This morning it would not start at all and the fuel pressure had dwindled all the way down to 2psi.

 

You have a fuel leak. Something is allowing pressure to leak down. The 10psi test is to determine if the check valve is the cause and if it held, then the check valve is ok. Sounds like a problem in the plenum. Pop the top and have a look for leaks.

 

No apparent leaks but I did find that the red lead on the spider assembly had come out of the connector. I got it back in, with the help of aluminum wire to tie it in place, but wanted to see what the symptoms of this being unplugged would be before I button it all back up.

 

A wire off of the injector would not cause your fuel pressure to bleed down. You have a leak.

 

I changed the pump, something told me it was bleeding off I am only losing 5psi after 10 minutes now. The damn thing still will not start on it's own. It will only react to ether in the intake and that only lasts for a second.

 

I suppose it is possible for a regulator to not seal properly. Not a typical failure mode though.

 

I changed the pump, something told me it was bleeding off I am only losing 5psi after 10 minutes now. The damn thing still will not start on it's own. It will only react to ether in the intake and that only lasts for a second.

 

Have you replaced the connector on the injector?

 

No I have not.

Do you know what the voltage is supposed to be at the connector?

Do you know if the injectors will fire with the upper plenum off? I would like to be able to visually verify if the injectors are firing.

Do you know what timing method the injector unit uses to fire and what drives that method? ( Crank/cam sensors or mechanical )

 

The PCM controls the IP (injector pulse) to the injector. It is timed via the CKP (crankshaft position) and CMP (camshaft position) sensors. The IPW (injector pulse width) is modified by the O2 sensor readings to maintain proper AFR (air fuel ratio).

IIRC, the connector should have full battery voltage across it as the PCM only grounds the connection. One wire should be +12V at all times with the key on.

Given that the IPW is in the realm of a few milliseconds, you may not be able to accurately read the voltage across the connector. A noid light is typically used to see if power is getting to an injector.