blazertom

1990 Full size 4WD Blazer w/5.7 liter TBI engine. My problem is the fuel pump continues to run after I turn the ignition off! Initial problem was the engine would not start. Found bad fuel pump and blown ECMB 10amp fuse. Replaced fuel pump, ecm module, oil pressure switch, ECMB 10amp fuse. Now when I turn the ignition on I hear the fuel pump turn on for two seconds then turn off, start the engine and it runs.

The problem is when I turn the ignition off the fuel pump continues to run. I can hear it very easily. I have been disconnecting the positive battery lead to shut the pump down.

When I use my code scanner it flashes 55 "CALPAK" error. Will that cause my problem? This is driving me nuts!!

RABarrett

My suspicion is that the relay is sticking closed. This may be the result of the pump's drawing excessive current. You might try locating the relay. Using a multimeter, locate the pins having 12 volts on them. If only two, the relay is sticking; if three, the ECM is telling the relay to stay closed. This could also be the result of a wiring problem, shorting 12 volts to the ECM signal line. Ray

Glenn Peters

EXORCISM, they work very well on Chevy's.