jmack91z28

Theres a ton of things to check when theres a strange problem like this. In my experience it's always been something like clogged fuel filter or a clog in the fuel rail, or a bad computer or chip. Where in the fuel system are you checking for pressure? You said you bought a new computer for it, where did you buy it at, and could it possibly be the chip?

Tuner

I took the fuel pressure at the inlet to the injection system at the factory schrader valve. This was with the schrader valve removed so it could not hold pressure at the gage. It's getting enough fuel to foul the plugs so I think it's a spark problem. The haynes manual says I should see 5V output on the crank sensor and I'm seeing only 2.8. I get the same reading off three crank sensors (the two I tried besides the original were used). I still have to believe the crank sensor is not the problem. Any ideas.
Thanks for all the input, You guys are great.
Tom

jmack91z28

I'm pretty sure there's a camshaft position sensor too, did you check that? How about the wiring from the sensors to the computer?

rockmaples

Did you clean the egr valve?

shawnvw

Sounds like one of those things where the problem is so simple, its take 3 guys, 3 days to figure out.I hate when that happens haha

So lets go back to the basics, really sounds like an intermittent poor connection. start by checking all grounds, everywhere under the hood. battery terminals etc. when it doesn't start, check for proper voltages at various sensors, computer, coils, and also the grounds. Check the resistance of all ground to the battery. Should be less than .5ohms.When its not starting, can you communicate with the computer with a scanner?

Tuner

Yes the PCU link is fine and the information I recieve is what I would expect. Nothing out of range. Is it possible the theft deterrent system on a 97 shuts down spark not fuel???

northey87