Technical 56 oldsmobile rocket 88 power loss when starting

I'm not sure if anyone can help me here, but im out of options and ideas. I rebuilt a 56 olds rocket holiday 88. I rebuilt everything on this girl except a new wiring harness. It all looked good and I went with it. It started up and ran great when I finished her.

After sitting for the winter I tried starting her and it started a couple times fine. Now when I turn the key, the dash lights turn off and there is no power at all. The wierd thing is, after 10 min I turn the key and the power on the dash comes back. When I try to start though, the power all cuts out. Won't turn over at all, but after a while the dash lights come back on. So its when I go to start that it kills everything. I thought it was the battery but when putting the multimeter on it and turn the key. It doesn't drop voltage at all. I thought it may be a bad battery and when a load is on it maybe it would drop to 9 or 10 volts telling me its a bad batt. It didnt move the voltage at all though. So now im really confused. I went to start it remotely from the solenoid and it did turn over once, but now it won't even turn over that way for some reason. It has power going to the solenoid. It has power going to the ignition. I just bought a new ignition because the last one burnt up while charging the battery.

All I can think of is maybe the new ignition is bad now, and when I turn the key its grounding something out. I just dont know why it has a time delay before it gives me another chance to start her. Its wierd. All the fuses are good. I checked the grounds to the frame and engine, and re wire brushed them to shiny metal...im lost, idk what's going on here.

Can someone please drop some wisdom on me here and give me an idea about this wierd behavior. There is a purple wire next to the starter relay and regulator. It goes into the harness and connects to the starter silonoid. Then the other end goes to the ignition switch in the dash. I use to be able to pull apart the wire connection in that wire under the hood, and it would rest the power back without waiting for it to randomly come back on to try and start her again. That plug connection is very clean as well.

Please help. Any suggestions are more ideas then I have at this point.

Thanks guys,
Mark

 

You have a high resistance circuit somewhere. The fact that things go out, but the battery voltage stays the same tells me you have a bad connection somewhere. The first place I would look at is the battery cable connections. Put the voltmeter leads from the post to the cable (do this both positive and negative). Turn the key to start and see what the meter reads. It should be zero, but if there is a bad connection at the battery post you will see a reading, possibly as high as battery voltage. If I was guessing, I'd guess a negative side problem.

If the test at both battery cable read less than 0.5 volt, you need to do additional testing. The next thing I would do would be to connect the negative voltmeter lead to the battery negative. Then connect the voltmeter positive lead to the battery terminal of the starter. You may have to use jumper wires to do this. Turn the switch to start and read the voltage. If it goes real low, you have a high resistance connection between the battery and the starter terminal. Either a poor connection or a bad cable. If it stays at battery voltage, move the positive voltmeter to the starter case. You are connecting the meter from ground to ground it will read zero or very close. Turn the key again. If it stays real near zero, it means there is a problem in the starter (I don't think this is what you will see). If it reads anything above 0.5 volts, you have a ground circuit problem between the negative battery cable and the starter. This will also turn other things off in the car.

It is possible that you get good reading on the starter test. This would point me towards the circuit that supplies power to the ignition switch. I would repeat the test at the ignition switch to see what happens when you turn to start (leave the voltmeter negative cable attached to battery negative).

 

Clean both ends of your battery cables, and the cable going to the starter. Clean and sand them even if they look good. Clean the ground strap on the engine also. I bet that will fix it.

 

Well I feel pretty dumb at this moment. I will say, you were dead on. I scrubbed all my points of ground and the starter. Tried after every point. It ended up being the starter silonoid ignition wire, the purple one.

Thank you sir. You saved me a lot more time and headaches? Good man.

Mark