Fuel pump problems on 87 chevy 305 tpi
Ok guys
This is my problem, turn on the ignition switch, and i cant hear the pump turn on. Thought it was Fuse by the battery, that is ok, replaced the fuel pump relay, and that was alright. The relay is getting 12 volts so i worked my way back i took out the connector behind the backseat right above the rearend. I checked it for corrorison it seemed fine. I checked the wires before it goes into the connector in the rear and it read like 10 volts then i checked the wires after the connector,wires closest to the pump, and it read like 8 volts.. So right away i am not getting my 12 volts that i need to run the pump. I need to get 12 volts to the pump to make sure it is working? How could i do that without burning anything up. what is the deal with this, is that connector my problem??? or is maybe something in my switch in the column.. Also i noticed that when i turn on my head lights the dims are VERY DIM and when i put on the brights only 2 lights light up and the other 2 go completely out,,,, Do i have some kind of electrical short somewhere that is causing these symptoms?? Any advice is appreciated, please help it is driving me crazy.
thanks
John

 

Dim headlights coupled with other problems is a sign of a battery problem. You need to put the lights on with the engine stopped, and see what voltage you get from the battery.

Don't measure across the terminals first, measure from the alternator and the engine. Then work back to the battery to see if the battery has full volts, but you are lossing it somewhere.
You have to have a load on, like the lights, otherwise there will likely be full voltage anyway.

 

Thanks for the response, but it is a brand new battery so i am thinking that it wouldnt be the battery. However one thing i noticed that on the negative battery cable there is a ground wire going from the cable to the passenger side fender, that it got hot or something at one time because the wire is showing completely through the insulation. What would have caused that, is that maybe where the problem is?? All i know is that i am not getting 12 V all the way back to the pump. So i cant start it or anything.. I checked the codes and there were no codes besides the 12. Anymore ideas.
John

 

It would take a lot of power to melt through a normal earth cable. The only way that would normally be expected to happen is is the supply side had a major short to the body, possibly a wrench shorting to ground.

Is it a the correct cable? It should be about a quarter inch or more in diameter?

If the cable overheated it might have a poor connection at the body, and that will cause the problem with low voltage. It will also prevent the battery from charging up properly.

It sounds like you need to completly check out and maybe replace the ground cable. Also check the engine to firewall earthing cable.

I suggest you check the resistance between the battery and the rest of the car, it sounds like that needs to be cleared before looking elswhere. Maybe also recharge the battery if you have a charger.

 

what happened to that wire that looks bare is that the ground from the battery to the engine is/was bad/corroded and the STARTER grounded throught the body, through that wire and burned all the insulation off, that wire at the time was glowing bright white, check all your grounds, make sure your shift cable isn't melted (I've seen the starter ground through it), replace that melted wire at the battery and then go from there