I have a 302, new 900 cranking amps Everstart AGM battery, load tested, good, new OReily’s Ultra starter, new Cole- Hersey metal body solenoid, new Alternator, new Voltage Regulator, all wiring and connections double and triple checked, ground, #2 wire from battery to engine block, hot lead to and out of Solenoid #2 wire, Voltage at end of starter lead and out of starter button matches battery But the starter will not engage if the battery is 12.72 volts. The battery has to be 12.85 vots or so for the starter to engage. If it o is at 12.72 the starter will not engage, the Solenoid clicks. These starters for these older engines need a a lot of voltage?

Thanks
mjac

 

New means nothing. If you got power/ground to the starter, it should engage. If it does and will not crank over the engine, the engine is either seized or the starter is no good.

It's a starter and starters about as easy as it gets when it comes to testing. Don't over think it.

Google voltage drop test. Come back with the results of those tests.

 

Did a voltage drop test, connected the leads of a Fluke Multimeter to the negative and positive terminals of the battery, hit the starter button and the voltage did not drop below 12v.

The starter and engine turn over fine, when the battery is around 12.85 volts or higher. But if the battery is at 12.72 volts, only the solenoid clicks and the starter does not turn over. I am trying to figure out why the starter needs so much voltage to turn over.

Thanks
mjac

 

That is not a voltage drop test. Google it so you understand what this test is for and what you can learn from it.

To do a voltage drop test on the starter lead, you would put one lead on the battery positive post [not the clamp, the post]. Put the other lead at the starter terminal. Not the clamp, but the terminal. Then crank it over. The number you see will be the test result. In a perfect world, the reading would be 0V. Because you got resistance with all those connections and cables, you will have some voltage change.

To make it simple, you would have 12 at the battery, but you might have only 9v at the starter. That means the voltage drop is 3v. 3v is a lot. Do this on the ground side too.

To break this test down in baby steps, put one lead on the battery post, then the other on the battery clamp. Crank the engine, because of the short distance, it should be darn near nothing. If you see 1.0v, then you are losing 1 volt at the clamp connection.

This should also be done on the ground side of things. Just start at the ground post [not clamp].

As a butcher, I would drill a small shallow hole on the battery post [not too deep] and put a small screw in it. That way, I can attach my test lead to the post easier.

It's a lot like an ohm test, but this test is done when current is flowing. I cannot stress this enough, if you have no current flowing, then you are not doing a voltage drop test.

Google it because I know what I am thinking, but it does not always come out right on the keyboard.

 

Yes, I saw that procedure when I was looking for how much voltage drop was acceptable. I have not done that yet. Is it accurate that the test I did tests the battery and the voltage drop test tests the circuits?

Thanks
mjac

 

The test you have done would not help me if I was looking for a problem. I am assuming the leads are on the clamps. If the clamps have a connection issue, then that would not indicate if the battery is good or bad. That is why with a small screw in a battery post, it makes it easy to start at the source. Make certain when you close the hood, the screws won't hit the hood.

Many people don't do tests, let alone voltage drop tests. Once you have done that test, it's a go to test when checking circuits under load. I can't stress enough, there must be a load. If you hook up the leads to the starter and battery and don't try to engage the battery, you are testing nothing since current is not flowing. You might as well do an ohm test.

 

I can get a good connection between the actual battery post and the multimeter leads to insure an accurate test. That is no problem. I did the test I described to you in the past where the motor would turn over but it was very sluggish and slow, barely turning over and the battery showed 13.2 volts on the multimeter and would go through the complete charge cycle with a NOCO Genius 5 charger. So I thought it was the starter, the starter button, solenoid or the circuit. But when I tested the battery under a load, I call it a load test, the voltage dropped to 4-5 volts which I was told indicates a bad cell and it was. Changed batteries to the Everstart AGM all problems disappeared. So I thought somehow I had a bad cell in this new battery, but it checked out good. I was calling a battery load test a voltage drop test.

I guess the next step is to do an actual voltage drop test on both the negative and positive side to see why the battery has to be around 12.85 volts to engage the starter. If the circuits test out good, I do not know what else it could be.

Two questions, should 12.7 volts be enough to engage the starter and turn the engine over and what is the difference between a voltage drop test and an Ohm test? The voltage drop is more accurate?

Thanks
mjac

 

It will be called good to go.

Something is not good and making the right tests will prove what it is. Thinking a new part is a good part is flawed. New parts can fail too. People just assume that if it is new, then it is good and therefore, it can't be that.

If everything is good, it will be working. Battery, wiring, or starter. It's that simple. Of course, the engine can be seized, but let's not go there until you test everything.

 

It looks like the battery checks out good. I thought I might have shorted it out when I propped the starter lead against the frame to get it out of the way when I installed the starter. But with the fender wall mounted solenoid not engaged the starter lead was not even hot. So the next step is to check the circuits with a voltage drop test and go from there. One step at a time.

The starter and the motor spin just fine, but it takes 12.86 volts to do it, 12.72 volts will not engage the starter for some reason.

Like old Joe Magavio said, if its fixed right, it will work every time

Thanks
mjac

 

Just to reiterate, your "new" starter from O'reily won't even turn if the battery voltage drops to 12.72V? I would take it back to O'reily to have that checked out.

Most starters should at least turn at as low as 9 volts applied voltage, though slowly.

 

That is the crux of the matter, but I do not know if it is the starter, it may be the Solenoid. At 12.72 volts the Solenoid clicks, like when you have a dead battery. I don’t know if a charge is even reaching the battery. I can check the circuits using the voltage drop test but I was having a lot of trouble with oem solenoids, sticking, burning up, posts pulling out, so I bought a cole-hersey metal body solenoid. This solenoid is not vehicle specific, just a general automotive solenoid. I am thinking maybe it takes really high voltage to activate. Or maybe it is the circuit. But that is what it is doing. At 12.86 volts or there about, the motor spins like a top.

Thanks
mjac

 

I'm not there so take my comments with a grain of salt.

You really seem to be caught up with voltage. Sure, it's important, but so is the current available. You can string up a few AA batteries to get 12v but that would not supply enough to supply the current to run a starter.

If you don't want to do a voltage drop test, let us know what is the voltage at the starter during cranking. Put one lead on the battery negative post and the other lead at the large cable at the starter.

 

No, I fully realize the value of the voltage drop test, it settles the issue once and for all, it tells you the current actually reaching the component, not just a voltage value. Voltage is useless without current. I found that out previously when the starter would barely turn the motor over, I had 13.2 volts at the end of the hot lead running to the starter so I thought everything was good with the circuit so it must be the starter. It had 13.2 volts, but it had no current because the battery had a bad cell. If I had done a voltage drop test I would have found the battery sooner before replacing the starter. A load test on the battery itself showed the bad cell with a voltage drop to 4-5 volts.

So, the first voltage drop test I am going to do is the hot lead running from the starter button to the fender mounted solenoid. I don’t think it is getting enough current. It clicks with the battery st 12.72. Then I will do the voltage drop test on the negative and positive side of the starter circuit. Tell me if I have this right. I will disconnect the coil, put the multimeter leads on the positive battery post and the solenoid terminal, hit the starter button and see what the meter says, if it is way above .2. How does that sound?

Thanks
mjac

 

If you had 13.2v to the starter with it engaged, I would question why the voltage was too high. I can only suspect you have a battery charger on it. Take that off if you are testing. You don't want it.

What about the ground side of things. All the current must start and end at the battery. If indeed you have 13.2v at the starter, I would look at the entire ground circuit. Matter of fact, if it was my 30 year old truck, I would not even make the test. I don't believe Ford properly grounded the engine/body so I would just replace everything and do it my way. While I was there, I would beef up the alternator/starter power cables too.

 

A lot of issues here, I will try and take them one at a time. I din’t know at the time the importance of voltage drop and testing everything under load. All I did was check the voltage at the end of the hot lead that hooks up to the starter. Assuming it was getting enough current from that static test led to all kinds of problems. The engine is grounded to the battery very well, I have a #2 cable from the negative battery terminal bolted to the engine. Now the ground from the engine to the frame, I don’t know and I think that is causing some problems. The lines from the positive battery post to the solenoid and from the solenoid to the starter have been beefed up with a #2 cable with crimped copper end eyelets. So that is not a problem. That is why I did not think it was those circuits but may have to be checked. Now, I talked to the tech guy at Cole-Hersee and he enlightened me about several things. One, the Cole-Hersee Solenoid activates at 9 volts, so that is not it. Then he said the problem is often the Solenoid is not properly grounded to the fender wall because the fender wall surface is dirty or corroded causing high resistance. Mine is sanded and wiped down with brake cleaner but I do not know how well the engine is grounded to the frame at that point. He says that is why he always recommends a four post Solenoid so you can run a ground wire from the solenoid directly to the negative battery post. So he suggested to take a nice wire, put an eyelet on the end tuck it under the solenoid mounting bolt on the bracket and run it to the negative battery post. Right now that looks like what it might be but I don’t know until everything is tested. Sorry for the length…

Thanks
mjac