1995 Chevy K2500 recently replaced fuel pump ran great for an hour then cut off blown ECM B fuse replaced blew again and again, if this is caused by a bad fuel pump how do I confirm so I can remove and take back for replacement
chafed wire or melted connector in harness between fuse and pump can be causing fuse to melt as amps required exceeds the fuse rating. Find what connectors exist from there to there and inspect for resistance causes of any kind. check harness for chafed screwed or damaged. if the new pump was trying to pump dirt? well, there you have some excessive pump laboring. What did tour in-tank filter look like? are filters new ? Is the pump connector making contact but with resistance excessive? Not exactly harry homeowner's after dinner project, But U-CAN-DO-IT ! ask as you go and I will see if I can be more help, lets see, ground is within spec? gry wire feeds pump, theres a relay under the hood, you can jumper it. Service manuals can be requested from many types from the library. cjilton, motor, and mitchell are in house reference type. Databases have schematics and connector and ground locations. good one is in house at our library. Then you would have drawings and schematic, etc. Some websites have diagrams but they are hard to identify as correct. research can simplify but takes time.
Thanks my next job is to check the wiring out of the fuse box back too the fuel filter. I will also check the wires out of the tank from the pump to ensure a wire is not pinched when I lowered the bed back down
yeah and the door opening panel at the carpet can cap the area where the harness comes up and goes forward to that fuse panel. if any work was done there. or connectors in that area can mate loosely or suffer heat damage, inspecting crosses them off your list of connections to verify, but I like the recheck of the harness below if you had the bed out of position. The connector on top of the pump is most often mentioned for the C/k truck, not for fuse but for somtimes stops running the pump. Wad of goo protects it from the wet, kinda messy but wiggle testing is no problem. if you were reading before and after at that, the resistance would be the connection, looking for less than 1/2 ohm on any wire thru any connector. test with battery cable off.
I did as you suggested and pulled up the door opening carpeting strip and inspected wires and harness out of the fuse panel and all the way back to the tank and fuel pump and found no obvious problems with all. I did charge the battery and just as a try put in a new fuse in the ecm b and it did not blow and the truck started. Tank has about 15 gallons of clean new gas, I replaced the tank when I broke off the tank ring lock when I replaced the fuel pump. The question now is did I move the problem which I was unable to see. Any suggestions
Was there no connection that had over a 1/2 ohm reading? for the wire that is fused there at ecm b ? and the ohms to ground reading...did you take one for each ground wire?, body ground engine ground and battery neg read within .5 ohms of one another? Then if it acted up again, you could have that fuse protected with a breaker you reset, like out of a toyota, or carry some fuses. could it be behind the fuse panel, you could find how many circuits are using that fuse and fuse them separately for each. difficult, but if you have to drive it you may want to improvise.
What was your fuel pump connector like, fits tightly? ground supplied well ? and if there are a few circuits that use that fuse, you can use inline fuses and divide them. monitor while using the vehicle, and get more clues from it. They make weak stuff anymore deliberately, to get the thing to stop working rather than operate while drawing too many amps, so you want to disassemble and inspect.
The other wiring, the fuel pump relay, and the ecm wiring are the other side of the circuit. find the vehicle harness grounds and see if theres an issue
If the gry wire is fused on your truck, by that fuse. and you had the fuse removed and the gry wire at the pump connector was unplugged from the top of the tank, you could read continuity to show that wire is good fron there to there....If that wire shows ohms to ground continuity? it's shorted....................If that pin on the pump and sender assembly has continuity with ground, you may need to re inspect how it is assembled in the tank? If your schematic shows that fuse and the nomenclature for the fuse lists what circuits are protected you can inspect those, looking for issues with shorted problem. Seems to me the fuel pump relay would get the ground from the ECM, making the relay switch and let power flow to run the pump. I do not have your schematic here, but when you blow a fuse its using amps and finding ground for them, but where? I dont have the truck here either. I would suggest autozone website for schematic and google the m.m.y. and fuel pump schematic. or fuses, or ecm b fuse problems, etc. This can take hours with the clunky computer I am using. also, the public library has auto database and you can print for a quarter, I use landscape and try to get them legible. Try trace the circuits and answer the need before leaving there pretty much is what I have to do.
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