Wiring question

[1stford]

I’m struggling to work through an issue with getting my starter to turn over. I believe it’s a ground issue and was hoping someone with some expertise around that topic could be helpful. If so could you message me with contact info.

Thanks.

[JSeery]

Some of the common issues are wire size, connections and grounds. A 6v systems requires a larger gauge wire than a 12v system, but they both benefit from a larger gauge wire from the battery to the starter solenoid and from the solenoid to the starter itself. Most auto supply store starter wiring is not heavy enough gauge for a 6v car/truck. All of the connections need to be very clean bare metal and a little grease on each connection helps. Grounds are a big deal, you need good ground wires to bare metal. The starter itself needs to be mounded to a paint free, clean bare metal surface. The engine, body and frame need to be grounded to each other.

[1stford]

It’s a 6 volt system. I had this same issue before and I fixed it by putting a ground from the bellhousing to the frame. Everything was perfect after that. I had to pull the motor out to fix an engine issue and I put everything back as was. I now have the same issue as before the ground strap went on.
Battery side of the starter solenid is 6.4-6.5 volts. When I open the solenoid only 2.4 come out.

[1stford]

Originally Posted by JSeery

Some of the common issues are wire size, connections and grounds. A 6v systems requires a larger gauge wire than a 12v system, but they both benefit from a larger gauge wire from the battery to the starter solenoid and from the solenoid to the starter itself. Most auto supply store starter wiring is not heavy enough gauge for a 6v car/truck. All of the connections need to be very clean bare metal and a little grease on each connection helps. Grounds are a big deal, you need good ground wires to bare metal. The starter itself needs to be mounded to a paint free, clean bare metal surface. The engine, body and frame need to be grounded to each other.

What gauge wire is needed from batter to solenoid and solenoid to starter? That would seem to not be my problem though if it worked prior?

[JSeery]

Originally Posted by 1stford

What gauge wire is needed from batter to solenoid and solenoid to starter? That would seem to not be my problem though if it worked prior?

I would not think it is a wire gauge problem as well. Not sure what size works the best, but I would use "0" or "00" gauge myself. My guess would be a connection is not right somewhere. Take each one apart one at a time and clean them, grease them and retighten them. Also, might not be likely, but wires do corrode internally, see if the wiring looks in good shape. It could be a bad starter solenoid, have you tried jumping across the solenoid?

[1stford]

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Originally Posted by JSeery

I would not think it is a wire gauge problem as well. Not sure what size works the best, but I would use "0" or "00" gauge myself. My guess would be a connection is not right somewhere. Take each one apart one at a time and clean them, grease them and retighten them. Also, might not be likely, but wires do corrode internally, see if the wiring looks in good shape. It could be a bad starter solenoid, have you tried jumping across the solenoid?

How do you jump across the solenoid? I’ve neber used wire grease. What is it for and where does it go?

[flatford8]

Does it turn slowly or not at all?..... what was the motor issue? what had to be done to the motor?...... Mark
PS....you can use a battery jumper cable and go from one lug to the other on the solenoid and see if it cranks over.

[1stford]

I’m not sure what PS is?

The motor had exshaust getting into the radiator. We pulled it out to check everything and it seems as though new head gaskets have fixed the issue.

[JSeery]

The grease can be anything, it is just to help keep the metal clean and stop corrosion. You can use di-electric grease, but I don't.

PS is just a notation for Post Script, and add on at the end of a letter or posting. It is like an after thought.

You can use anything to jumper across the solenoid, a pair of pliers (handles) will do it. But there is a lost of current involved (it will spark like an arc welder!) so a jumper cable would be a little less exciting!

[TJ]

If you are using the braided ground straps they do corrode and could be your problem. Personally I don't use them.

[rotorwrench]

A lot of battery set ups for 6-volt systems have the ground cable connected directly from the battery to the engine to prevent starter grounding problems. The flat braded ground cables work OK as long as they are in good condition. Some are good quality and some may not be so I always look for best quality of wire for stuff like this. The starter relay should only require a ground to get it to function just as the starter button provides.


If you have good cables with clean connections throughout then your problem is with the starter. Bad bearings or worn out brushes would be the more likely causes of failure. A bad armature or field windings are also a possibility.

[1stford]

Originally Posted by JSeery

I would not think it is a wire gauge problem as well. Not sure what size works the best, but I would use "0" or "00" gauge myself. My guess would be a connection is not right somewhere. Take each one apart one at a time and clean them, grease them and retighten them. Also, might not be likely, but wires do corrode internally, see if the wiring looks in good shape. It could be a bad starter solenoid, have you tried jumping across the solenoid?

When I try to jump across the solenid it does nothing except spark. On another note it seems my problem is voltage dropping. If I touch the cable from battery to solenoid it’s 6v. As soon as I hit the starter it drops to 1.5-2 volts.

[JSeery]

That appears to be a starter problem.

[Bob C]

Are you sure the starter is not jammed?

[petehoovie]

The starter pinion gear might be hung up on the flywheel ring gear. Put the car in high gear and then rock the car back and forth. You will hear a click sound when the gear releases....

[1stford]

I have no ground from the body (Cab) to anything. Should there be one and if so where?

[JSeery]

Originally Posted by 1stford

I have no ground from the body (Cab) to anything. Should there be one and if so where?

Yes, but don't believe that has anything to do with you current starter issue. The problem is the starter itself. It is ether installed wrong, jammed on the ring gear or defective.

I would have a ground from the body to the engine and from the body to the frame.

[rotorwrench]

The battery may also have problems. On a high rate discharge test, the battery can drop off to little or nothing if it is all sulphated up or has bad internal plate connections. The battery should hold a good percentage of its voltage when the starter is engaged.

[Flathead Fever]

Originally Posted by 1stford

When I try to jump across the solenid it does nothing except spark. On another note it seems my problem is voltage dropping. If I touch the cable from battery to solenoid it’s 6v. As soon as I hit the starter it drops to 1.5-2 volts.

With both leads on the battery if you are seeing 2 volts across the battery while trying to crank the battery it is not charged or its gone bad.

When you measure the voltage anywhere in the circuit except directly across the battery terminals "while the circuit is energized" you will only see how much voltage is being used up by the resistance between your two meter connection points.

If you had the meter hooked to the starter terminal and the other lead to the starter case. You will see zero volts until you try and crank it. Then you should see almost the full battery voltage drop across the starter.
You main voltage drop would be a cross the starter terminal and the starter housing. That's because the starter is where all the resistance in the circuit is located. If you only see 4 volts across the starter than somewhere else in the circuit excessive resistance is dropping the voltage 2 volts.

Voltage is the same as measuring water pressure. So you can only test the circuit with the pressure turned on. That means the circuit has to be energized. Everywhere there is a blockage (resistance) it will force pressure to try and go around the blockage and through your meter. Example, you put both meter leads on each end of a battery cable. When you try to crank the engine the pressure (voltage) going through the cable should nut put any pressure on your meter and it will read zero volts. Because a good cable or connection does not offer any resistance. The cable is large enough that it can flow all the amperage needed to operate the circuit. Now if there is a bad spot (resistance) inside the cable, say only 4.5 volts can get through the cable. The other 1.5 volts that is blocked by the resistance looks for another path to flow. It finds a path through your meter leads. The voltage meter being an electrical pressure meter measures that pressure at 1.5 volts.

All the voltage drops need to add up to the battery voltage. You keep hooking up your meter test leads across cables, connections, relays..... then crank the engine and see what the drops are between your two leads. You do this until you find every missing .1V piece of the battery voltage.

You should have no more than .1V drop across any cable or connection. That includes between the battery post and the battery cables end.
.
If you see 2 volts between the starter solenoid and the battery when cranking then you have a 2 volt drop in that cable or its connections. If you put your leads on each end of the starter solenoid, crank the engine and see 1V you have a 1 volt drop across your solenoid. If you put a test lead on the positive battery post and the other lead on the positive battery cable. Crank the engine and see .4V then you have a bad connection between your battery cable and battery post.

What you are doing is performing a "voltage drop test". This is the best way to find bad cables, connections and components.

Something else you can try is to take a pair of jumper cables and connect one cable from the battery ground terminal to a starter mounting bolt. This bypasses all your ground connections and cables. If it cranks then you have a problem on the ground side of the circuit. Most jumper cables are poor quality and the cable sizes are too small. On a 6V system it requires twice the amperage to do the same work as a 12V system. That is why the cables need to be larger on 6V circuits to carry all that amperage.

[chap52]

I would first pull the battery and take it to a local auto parts store and have it load tested. This is usually a "free" test. If it is junk and it is 6 volt check a Tractor Supply for a heavy duty 6 volt battery that will fit. Chap