Battery, starter motor, starter solenoid, or something else?

[A.marra]

Hey yall!

My partner and I are at the end of our demo process and we came across an interesting problem the other day...

Context.. The bus has always started fine for us before this point. Not even a whisper of a problem. On Saturday, our goal was to remove the AC wires from the electric panel since we didn't have a working unit and it was already decommissioned and unplugged anyways. we disconnected one of the emergency windows at some point but plugged it right back in before turning the bus on.

Heres whats up... We disconnected the battery and began to disconnect the rear AC wires from the electrical panel (thinking that it shouldn't affect the bus from turning on) and then reconnected the battery to try and start the bus but it didn't start. So we started reconnecting wires to the electrical panel to put it back to exactly how it was before we disconnected. Once or twice the bus was able to turn over and start running, but eventually, it wouldn't start or even fully turn on. Sometimes the dashboard lights flicker and you hear clicking noises. If you let it flicker and click in the on position for 1 minute it eventually turns on, but it still won't crank to start. Sometimes you hear the starter motor click but not start the engine. We tested the battery voltage and it was at about 12.20, which we thought should have been enough to start the engine no problem. We tested the voltage at the starter motor solenoid and it is also 12V. We tested the voltage at the starter relay and it is about 5 or 6 V. So we believe there is some sort of faulty connection in the starter/ignition circuit. Someone told us our starter motor may be faulty in general.

Just so we could knock out the easy stuff first before trying to diagnose a bigger issue, we charged the batteries up to 12.7 and suddenly she fired up just fine as if nothing had happened.

From the problems we were having it SEEMS like a starter motor or faulty connection problem, so we didn't think it would be the battery since the charge should have been enough to start the bus, but that seemed to fix the issue. Maybe it isn't the battery at all but we just happened to get lucky when turning it on after charging them? Or maybe there's an underlying connection issue from the battery?

Huge shout out to Will for helping us through this process!

[JESUSBUS]

Originally Posted by A.marra

Hey yall!

My partner and I are at the end of our demo process and we came across an interesting problem the other day...

Context.. The bus has always started fine for us before this point. Not even a whisper of a problem. On Saturday, our goal was to remove the AC wires from the electric panel since we didn't have a working unit and it was already decommissioned and unplugged anyways. we disconnected one of the emergency windows at some point but plugged it right back in before turning the bus on.

Heres whats up... We disconnected the battery and began to disconnect the rear AC wires from the electrical panel (thinking that it shouldn't affect the bus from turning on) and then reconnected the battery to try and start the bus but it didn't start. So we started reconnecting wires to the electrical panel to put it back to exactly how it was before we disconnected. Once or twice the bus was able to turn over and start running, but eventually, it wouldn't start or even fully turn on. Sometimes the dashboard lights flicker and you hear clicking noises. If you let it flicker and click in the on position for 1 minute it eventually turns on, but it still won't crank to start. Sometimes you hear the starter motor click but not start the engine. We tested the battery voltage and it was at about 12.20, which we thought should have been enough to start the engine no problem. We tested the voltage at the starter motor solenoid and it is also 12V. We tested the voltage at the starter relay and it is about 5 or 6 V. So we believe there is some sort of faulty connection in the starter/ignition circuit. Someone told us our starter motor may be faulty in general.

Just so we could knock out the easy stuff first before trying to diagnose a bigger issue, we charged the batteries up to 12.7 and suddenly she fired up just fine as if nothing had happened.

From the problems we were having it SEEMS like a starter motor or faulty connection problem, so we didn't think it would be the battery since the charge should have been enough to start the bus, but that seemed to fix the issue. Maybe it isn't the battery at all but we just happened to get lucky when turning it on after charging them? Or maybe there's an underlying connection issue from the battery?

Huge shout out to Will for helping us through this process!

Off the top of my head (because troubleshooting an electric circuit without a schematic or visual check is like asking Satan to crap ice cubes), I think that you have some screwy wiring. Normally, there is a large gauge copper stranded cable going from the battery positive to the starter, or in some instances through a starting solenoid like Ford's. However, the starter solenoid should also be rated for a 12V DC system. When you checked the voltage at the starter solenoid and it read 6V, that means that there is a voltage drop of the other 6 volts in that wire somewhere.

It's really hard to explain with words, but the wiring going to the starter solenoid is loose, or along it's path, it has it's insulation removed causing a short to ground.

Usually, what is most common is the starter solenoid does two things. It is an electric relay that allows full current to flow through the starter motor, and it is a solenoid, which creates an electric field which drives the small pinion gear aft into meshing with the flywheel gear teeth. At 6 volts, the solenoid cannot do this. So I would look closely at the wiring going to the solenoid and see that none of the insulation is frayed, and it isn't shorted out against the engine, manifold, chassis, or body.



PS I am a Floridian too! I grew up in Melbourne, although I am not Ausralian.

[ewo1]

Originally Posted by A.marra

Hey yall!

My partner and I are at the end of our demo process and we came across an interesting problem the other day...

Context.. The bus has always started fine for us before this point. Not even a whisper of a problem. On Saturday, our goal was to remove the AC wires from the electric panel since we didn't have a working unit and it was already decommissioned and unplugged anyways. we disconnected one of the emergency windows at some point but plugged it right back in before turning the bus on.

Heres whats up... We disconnected the battery and began to disconnect the rear AC wires from the electrical panel (thinking that it shouldn't affect the bus from turning on) and then reconnected the battery to try and start the bus but it didn't start. So we started reconnecting wires to the electrical panel to put it back to exactly how it was before we disconnected. Once or twice the bus was able to turn over and start running, but eventually, it wouldn't start or even fully turn on. Sometimes the dashboard lights flicker and you hear clicking noises. If you let it flicker and click in the on position for 1 minute it eventually turns on, but it still won't crank to start. Sometimes you hear the starter motor click but not start the engine. We tested the battery voltage and it was at about 12.20, which we thought should have been enough to start the engine no problem. We tested the voltage at the starter motor solenoid and it is also 12V. We tested the voltage at the starter relay and it is about 5 or 6 V. So we believe there is some sort of faulty connection in the starter/ignition circuit. Someone told us our starter motor may be faulty in general.

Just so we could knock out the easy stuff first before trying to diagnose a bigger issue, we charged the batteries up to 12.7 and suddenly she fired up just fine as if nothing had happened.

From the problems we were having it SEEMS like a starter motor or faulty connection problem, so we didn't think it would be the battery since the charge should have been enough to start the bus, but that seemed to fix the issue. Maybe it isn't the battery at all but we just happened to get lucky when turning it on after charging them? Or maybe there's an underlying connection issue from the battery?

Huge shout out to Will for helping us through this process!

At 12.2 volts your battery is already at 50% or less and if you have a bad cell that would cause it to drop even more, especially while cranking the engine. Since you said it cranks slow and you heard clicking sounds, battery is low.
My batteries went bad from just one year of sitting. When I tried to charge them back up they wouldn’t charge to 12.6. Tossed them, bought new batteries problem solved

As far as underlying issues, follow your battery ground wire to where it goes, engine block or chassis, disconnect, clean and don’t forget to add some protectant when your done.

[A.marra]

Originally Posted by JESUSBUS

Off the top of my head (because troubleshooting an electric circuit without a schematic or visual check is like asking Satan to crap ice cubes), I think that you have some screwy wiring. Normally, there is a large gauge copper stranded cable going from the battery positive to the starter, or in some instances through a starting solenoid like Ford's. However, the starter solenoid should also be rated for a 12V DC system. When you checked the voltage at the starter solenoid and it read 6V, that means that there is a voltage drop of the other 6 volts in that wire somewhere.

It's really hard to explain with words, but the wiring going to the starter solenoid is loose, or along it's path, it has it's insulation removed causing a short to ground.

Usually, what is most common is the starter solenoid does two things. It is an electric relay that allows full current to flow through the starter motor, and it is a solenoid, which creates an electric field which drives the small pinion gear aft into meshing with the flywheel gear teeth. At 6 volts, the solenoid cannot do this. So I would look closely at the wiring going to the solenoid and see that none of the insulation is frayed, and it isn't shorted out against the engine, manifold, chassis, or body.



PS I am a Floridian too! I grew up in Melbourne, although I am not Ausralian.

That's what we were thinking. It just wasn't making sense to us how charging the battery alone would fix the issue. It looks like we're going to be tracing those connections this weekend... Cant wait! Thanks for the comment

Also hey their fellow Floridian!

[A.marra]

Originally Posted by ewo1

At 12.2 volts your battery is already at 50% or less and if you have a bad cell that would cause it to drop even more, especially while cranking the engine. Since you said it cranks slow and you heard clicking sounds, battery is low.
My batteries went bad from just one year of sitting. When I tried to charge them back up they wouldn’t charge to 12.6. Tossed them, bought new batteries problem solved

As far as underlying issues, follow your battery ground wire to where it goes, engine block or chassis, disconnect, clean and don’t forget to add some protectant when your done.

Ours charged up to 12.7 but no further. Would a bad battery affect a vehicle's ability to turn over even if the charge should be sufficient like at 12.2 where we had it? I'm honestly hoping it's just a bad battery cause that's a hell of a lot easier to fix than a connection issue haha