<font color="black"> </font> :I was given a 90 Blazer, which had not been driven for about 3 years. It was started about once a month during that time. It's totally stock w/ 5.7L TBI. VIN # 1GNEV18K9LF166XXX. It was driven to our house and sat for 2 weeks. Then it would't start. What I know: 1. The fuel pump relay doesn't come on when the ignition key is turned to "on". 12V applied directly to relay coil (relay out of truck) makes it pull in and shows 0 ohm connection between proper contacts. 2. 12V connected to the "prime connector" on the fuel pump relay makes the pump run. Fuel comes out when the fuel filter connection is opened. I don't have access to a pressure guage but it does pump fuel.Sort of flows rather than gushes out? 3. O2 sensor was replaced as it was broken off(rusted) and hanging by it's wire. 4. Fuel filter replaced. 5. A voltmeter across the pump relay coil connector(relay out of connector) shows 12V but only for like 1 second. Then 0V. 6. Battery was bad and replaced. 7. No trouble codes show up. Just flashes 12,12,12 and repeats.(Yes, I checked that only AFTER replacing the battery /forums/images/graemlins/mad.gif 8. ECM fuses are good. I ordered the Helms factory repair manual (our local library had crap) but the weekend is here and the manual is not, so some questions: 1. Where is the oil pressure switch that keeps the fuel pump running? Where is the fuel pressure regulator I've seen mentioned on here? 2. Where is the brain thingy (ECM?)? And can it keep the pump from running? 3. Any other ideas? Thanks in advance for any help. This is a graet site! Special thanks to the member that had the fuel system wiring diagram on his website!