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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: A-Rod on February 04, 2016, 01:56:56 pm
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I recently change the fuel pump and the gas tank. I also change one injector but the other one is not working right but I'm able to crank it up until it blows the fuse. This is just one of my problems is also smoking like heck (white smoke). I'm guessing is a head gasket, for what I been reading on Internet. I need to know what can make the fuse that control my gas to blow. If some have any pointers that can help me.
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Specifically, which fuse? What is the fuse marked in the fuse box? And, what is the year and model of vehicle?
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87 Chevy Silverado v10
ecmb are the letters and is a 10 amp fuse.
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I'm not an electrical expert so correct me if I'm wrong. You should be able to measure the resistance of the pump to see if it is bad. Under your hood just to the right of the air box there is a rather large relay mounted on the fire wall. Hanging off of it should be a red wire with a plug not connected to anything. This is a diagnostic power wire to test the fuel pump. It will bypass the relay and send power straight to the pump. Using a fluke or something of the sort you should be able to measure the amperage the pump is drawing without having to cycle the key or anything else. But be careful because when you use this wire it bypasses all safety features and the pump will run until it is no longer receiving power...or worse.
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My fuel pump is less than a month old. Not saying that is not the problem. But Could a bad injector make that fuse to blow? It takes time for it to blow it is not right a way.
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The injectors and ECM receive ignition power through the 10-amp "ECM I" fuse. The 10-amp "ECM B" fuse supplies battery power to the fuel pump circuit and the ECM.
Replace the 'ECM B' fuse, unplug the fuel pump relay, then crank the engine to start and see if it continues to run without blowing the fuse.
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I recently change the fuel pump and the gas tank. I also change one injector but the other one is not working right but I'm able to crank it up until it blows the fuse. This is just one of my problems is also smoking like heck (white smoke). I'm guessing is a head gasket, for what I been reading on Internet. I need to know what can make the fuse that control my gas to blow. If some have any pointers that can help me.
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No need to guess.
If it's a head gasket the white smoke will smell sweet like anti-freeze. Easy fix. Have a machine shop flatten the heads. When you get em back install with new head gaskets.
If it's burning oil it'll smell like burnt tires or belts.
Oil smoke at startup that clears up in a few minutes is valve stem seals... Easy fix.
If it's a pest control vehicle leaving a cloud of oil smoke everywhere or just blowing oil smoke at idle, even when warmed up, then you have piston/cylinder area problems.
Since the power problem showed up after you performed service you need to look at what you disturbed... You changed an injector and the fuel pump.
The Injectors are on Circuit 439. Circuit 439 is fused by the ECM 1 fuse. You're not blowing that fuse... and since the ECM switches the ground side of the injectors we can move on from them.
ECM-B is Circuit 440. 440 feeds the Both plugs on the ECM, and the fuel pump circuit. This narrows it down a bit.
Since you had the sender out to change the fuel pump you removed the pump and sender/fuel-pump ground terminal from the frame.
My first thought is the tank ground is not making good contact. Amperage draw is inversely proportional to voltage at any load in a circuit...
If the sender ground is not making good contact the voltage at the pump will be low and it will draw more current than it should... Right around 10A in this case. You probably won't blow a 15A fuse but the fuel pump will run hot, the oil pressure switch and fuel pump relay contacts will get too hot and none of them will last long.
Sand the ground ring terminal till it's shiny and do the same with the frame around the screw hole till you have a good clean contact patch. Use an external tooth washer between the ring terminal and the frame. When you're done hose it all down with Battery terminal protectant or wipe on some grease with an acid brush.
Any of the Orange wires in Circuit 440 or the Tan/White fuel pump power wires in Circuit 120 could be pinched somewhere but try cleaning up the sender/fuel-pump ground first.
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Thanks to all the good pointer I found a ground wire that I forgot to bolt to the truck bed. I drove it all day today and it didn't blow the fuse. I guess if it dose it again I will check the ground to the fuel pump. I'm still working my way to get it running like it should.
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