Chevrolet Repair: 1988 chevy s-10 blazer, engine control module, battery voltage

Question
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Followup To
Question -
The problem that I am having with my blazer is that it wouldn't start.  The engine size is a 4.3 v-6.  The motor will crank over but will not start.  I sprayed some starting fluid on the part I think is the throttle, which is under the air filter, and the truck started.  I had asked a person at my local part store and he said that it could be the fuel pump.  I would like to know what you suggest the problem is.  If it is the fuel pump, is there any way that I can test it before I have to drop the tank to change it. Can you give me info on what to check please.  Your help is greatly appreciated.  THANK YOU

Answer -
Hi Ryan,
By all means, yes, check for power getting to the pump before just replacing it.
Reasons for power not getting to it can be...
blown fuse,
pump relay bad,
ground connection at the frame near the tank bad,
loose connection in wires,
ECM not turning the relay on,
pump running but filter plugged,
and bad pump.
You can find the connector near the tank, and check the wire powering the pump, I believe it is gray. See if battery voltage gets to the connector for about three seconds when the key is turned to run, or all the time during cranking.
You might also smack the bottom of the tank when someone cranks the vehicle, to see if you can coax the pump into working, but if the cause is a plugged filter, that won't help. But you should be able to hear the pump run for that three seconds if the filter is the problem.
Van


Thank you but can you please tell me what to test, what is ECM (also where is it located, and how can i tell if the relay is bad.  THANK YOU.

Answer
ECM= engine control module, or in other words, computer. They are quite dependable.
I would first listen to see if the pump in the tank runs for three seconds after the key is turned to run.
If not, check for power at the connector near the tank.
Injector fuse should be checked if the pump is working.
Check all the fuses anyway.
If pump is working, and inj fuse is good, get a pressure test on the fuel system.
Van