Hello All,
I have been reading a lot the threads (and I could have missed one), but I am not finding what I need. A little history:

I inherited my dad's 84 with 82k on it. When I got it, I knew it had some issues since it hadn't really been driven a lot and just sat in the garage. One being a leak on the rear right intake corner, so I pulled it all apart, cleaned it all up, rebuilt the throttle bodies since they were off and put it all back together. After fiddling around with the timing and pulling my hair out on trying to understand compression/exhaust and how to find both, I finally managed to get the timing right and the car started right up. Took it out, ran and up down the country roads, having a good 'ole time. Got it back to garage and noticed the water pump was leaking, oh man!! Well, as part of my inheritance, I also got all of the spare parts for the Vette and much to my surprise, a brand new pump!! Removed the water pump, deleted the smog pump, bought a new A/C compressor . New pump installed, cooling system flushed and topped off, A/C compressor installed, empty still, fired the car up, started right away with no issue. Another quick ripper around the countryside and back home. I did notice during this drive, the car felt a little off, so I thought I would verify the timing. As I started to loosen the distributor clamp bolt, the head twisted off . Ok, no big deal, new clamp/bolt, I took a picture of the rotor before pulling it out so I could make sure it went back exactly. Got the screw out, new hardware on and put back together...

Now the issue:
It will turn over but will die immediately.

I know everyone's advice, don't throw parts at it, but it's 40 yrs old, had a rough life in Alaska for a number a years, 2 teenage boys, and some years in Washington. That being said, a new distributor, ignition coil and ICS, verified TDC on compression same issue, the car will only turn over for a second and then die? I have a fuel pressure gauge between the throttle bodies, but I can keep the car running to get a pressure reading. I verified the voltage at the pump and there is 12v when I turn the ignition on for the 2 seconds. As far as codes, it just repeats the 12 code.

What am I missing here? Any help would be greatly appreciated.

Thank you. CO-84Vette
(The Vette is in Colorado now)

 

One possibility - and it is a relatively cheap and easy fix to try - new fuel pump relay. If you don't want to buy a relay just to try this fix you could swap fuel pump and A/C compressor relay - which must have tested as good because you mentioned you had successfully fitted a new compressor.

 

My mistake, I forgot to list that part as well. Also new injectors and fuel filter. I am trying to think of any other parts I might have forgotten but none are coming to mind.

But thank you for the reply.

 

OK - the only other thing I can think of is the oil pressure switch. It also plays a convoluted role in the C4 start/run fuel pump sequence and is designed to kill the engine if the oil pressure suddenly drops..

 

So I took the distributor off and the top plug on the oil sensor was off. Straightened out the prongs, verified both connections were good, but unfortunately the issue is still there. I was so hopeful seeing the top plug all bent out shope.

How do you determine if the oil pressure sensor is still working?

 

Sorry CO-84 Vette - I have no personal experience but I looked at AI Google for "how to test a 1984 c4 corvette oil pressure switch" and they have instructions for several tests using a multimeter.

 

What are you losing? Spark, fuel pressure, injector pulse?

 

When our '84 did this, I was stumped also, it turned out the fuel pump would flow fuel but not under pressure or enough to keep running once it started. changing the fuel pump on these is pretty easy

 

change the oil pressure switch.
I just had one fail on my 85,
When it fails it covers the motor , trans and driveway with oil.