Monday, January 28th, 2013 AT 2:02 PM
I have a '93 GMC Jimmy that was running fine then will not start. When I first tried to start it, it would run for 10-15 seconds when either the gas pedal was floored or the fuel pump was disconnected after priming. The fuel pressure gauge showed 60 psi with key on, engine off/on; though there is slow fuel leak down problem on the supply side. Testing the spark plugs showed that all plugs were getting current. After removing the air intake plenum, I noticed that the CPI was spraying a good amount of fuel. At some point during my testing the CPI quit spraying fuel. Upon testing the CPI system with ignition coil disconnected, the CPI will spray some fuel when I apply an external power source to the injector (injector solenoid can be heard). Testing the CPI leads shows a constant ~12 volts with key on & engine off. There is no sign of wire/connection issues. VOM testing of the injector and leads shows a resistance of ~1.5 ohms. Don't understand why it won't spray any fuel except when an external power source is connected. Any ideas?