Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
I am sending these ,this is for the chevy with an 8th digit of W which is more common...guy...
hi, do you have injector pulse? here are the pin-outs at the ecm check these out ,at this point I am more concerned if you have battery voltage with the key on at A6 B4 battery voltage at B1 C16 and grounds at A12 D1 D9 D10 , and at D16 there should be battery voltage with the key on ,also at the dk blue wires of the fuel injectors,on the other wire(s) at the fuel injectors there should be a pulsating ground signal when cranking over the motor ...guy...
I printed these large and small to make sure you can see these
Circuit Description: When the ignition switch is turned "ON," the ECM will turn "ON" the in-tank fuel pump. It will remain "ON" as long as the engine is cranking or running, and the ECM is receiving distributor reference pulses. If there are no reference pulses, the ECM will shut "OFF" the fuel pump within 2 seconds after ignition "ON" or engine stops.The pump will deliver fuel to the TBI unit where the system pressure is controlled to about 62 to 90 kPa (9 to 13 psi). Excess fuel is then returned to the fuel tank.The CPI pump will deliver system pressure that is controlled to about 370-440 kPa (54-64 psi). Excess fuel is then returned to the fuel tank.Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.
ok, let me know if you have a throttle body with 2 injectors on it , or if you have the cpi unit which has a wiring connector in the top of the motor ?
,ok at the connector at the tank disconnect that and on the harness that comes to the fuel tank sender unit connnector test the grey wire for battery voltage with the key on,it should read battery voltage for 2-3 seconds,then crank the motor over it should read bat voltage,if that is good the black wire is ground check this for a good ground and then while cranking the motor over see if it still has a good ground reading ,it it does then the pump is bad ,now back to no spark ,when you tested the pick up coil in the dist ,did you ohm out the pick up? that is hook up the ohm meter to each one of the wires ,it should read o.oo ohms or so ,if it doesnt that may be giving you a no spark situation
I had voltage at the fuel pump and while cranking, The ground stayed stable. The volate I read at the fuel pump was about 7 volts and it cycled while cranking. The pickup coil ohmed at 733 and while cranking the ohms cycled while cranking.
I think we have it nailed now. Using the chart for no fuel and providing 12volts to the fuel pump test lead the fuel pump does not run. Using the chart A4 following all the steps to completion it states that D16 if a light is on to check the connection at the ECM D16 so Guy I believe we have a bad fuel pump and ECM because I ran the test procedures to the exact letter. Let me know what you think buddy. Thank You David