Chevrolet Repair: Chevy Blazer, oil pressure sending unit, chevy blazer

Question
I have a 1987 chevy blazer that will not start quite often, one day it will and might work for 3 days or so and then it wont for a day or 2. I had someone turn over the engine while I looked to see if it was getting any gas and its not. It will start if I put gas in the carb by hand or spray it with starting fluid and then it will run fine. I have changed out the fuel filter and ignition coil, but I have still had the same problems. Is there something electrical like a relay that tells the car to feed gas to the carb when the engine is being turned over? I have been told the fuel pump is the problem but it doesn't make since to be that when it runs fine after i get it started when i put the gas in while someone cranked the car.

Answer
Hi Jon... usually what happens is that you don't have enough fuel pressure to open the injs. you should have between 9 and 13 psi if this is S10 blazer. check that the fuel pump relay is working, if not you have to crank engine to open relay bypass on oil pressure sending unit.that makes for a long crank time as fuel pump will not turn on until engine reaches certin oil pressure...if you turn key on fuel pump should turn on and run for 3 seconds...if not check the relay...if relay is ok check for power at the pump when key is on...should light test light for 3 seconds...if not you have an open in the circut, if it does then pump is bad....hope this helps