Since I don't have any experience with marginal fuel pressure and injectors I communicated with a senior member here (Swartlkk) to get some help for you. This was his response:

"With a new SCFI spider, it likely can go as low as 52psi before the pressure would not sufficiently open the nozzles. As the poppets sediment up with varnish & other contaminants, their pressure requirements will tend to rise along with their spray pattern deteriorating. Higher fuel pressure can mask dirty nozzles for a time, but only for so long. This is why the upgrade to the MFI spider is a good one as it removes the problem prone, pressure activated poppet nozzle from the system; moving the electronic fuel injector down into the intake runner. The MFI spider will spit fuel at pretty much any pressure. It might not send out the required amount if the pressure is too low, but fuel will squirt out of the injector regardless."

Did you upgrade your spider?


George

 

Ok Georges. Thank you for taking the time to inquire. It advances research.

I actually improved the spider.

I contacted a traveling mechanic who came yesterday. According to him, I have done all that is possible in classical diagnosis. We tried to start insisting and he says gasoline is coming. Your explanation would confirm this since 58psi is above 52 so it should be fine.

Change of track therefore. We decided to get a crankshaft position sensor because the initial symptom made him think of a failure of this sensor since the car stopped several times and started again before stopping definitively. I will also order a camshaft position sensor even if it looks like there is a spark.

Another possible cause would be the ignition switch, but the car would normally have stopped suddenly.

When I have received the crankshaft position sensor, it will come back to test the electrical circuit.

I have to say that after that if it doesn't start it will be sold for parts with great regret.

thanks again Georges

 

the security light/system doesn't factor in this, does it?m Just a thought...Jerry

 

This is a possibility that we will see during the test of the electrical circuits if the change of the crankshaft position sensor does not give a result ...
For the moment, the security indicator lights up normally. Having said that, in Europe we have a different immobilizer system than you have on US Blazers. And it is very difficult to add a key, especially since the frequency is not the same.