More opinions needed! 2 steps forward...one step?

[daddysgirl]

Hi all!
I hope everyone had a filling turkey day. I have no doubt we're all very thankful.

OK, so update to starting the green machine. I installed all the new cables for the 2 8D's; from the stud in the rear to the starter; and the ground.
I remembered either Clifford or Brian having the thought of unscrewing one screw off the stop cylinder and moving it just barely enough to prevent the stop lever from making contact. So, I did that, and pushed the stop toggle on the dash up enough to get the cover to close.

I turned on the battery, the master switch and hit the start button. Surprisingly, the starter did start turning. However, my son told me to kill it because there was a spark coming from the area between the power stud and neutral safety switch. On that stud, there are two large power cables coming from the battery compartment, and my new starter cable. Once I killed the battery switch, the sparks and the starter stopped.BUT...the sparks were NOT coming from the starter. The starter wasn't hot, but the cable up on the stud end was warm.

So (in addition to those of you blessing me with your help) I think one or both of the cables on the power stud with the starter cable has bare metal touching something. I'll investigate tomorrow, but wanted all possible input from you all?

And the only thing that has ever been connected to the starter (little switch terminal) is one of the two ends of the neutral safety switch. The other end goes to rear stud 12...no starter wire on the starter, but stud 12 is for both front and rear switches and those wires are on stud 12.

Anything?

On the better news side...all four new house batteries are installed and connected to the PD4500. So when I get around to the inside...I'll have heat from the roof units (the only connections I've made thus far...outlets will be next. But I'm going to get this bus started. It's become a mission for me...I know you all understand. Help?

[brmax]

I would be happy to look at a schematic if available. With that said I sorta hear the starter was still engaged and turning again "until" bat power was turned off,  say at battery? am I picking that up correct.

I'm thinking the stud you mention is an isolator type;  junction.
That the 2- 8d battery cable positive was connected, is this a typical short 4' engine start cable or the other end/part possibly long 35' cable to battery.

If all else is perfect, the starter solenoid copper plate is welding itself each time its triggered to engage and obviously not able to release. (however that happens)

I'm not sure on the connection of neutral safety wire location, and power wire, so a photo would be best.
No doubt a designed connection is sticking and or grounded and or loose. This needs wiring removed from bus and starter checked individually.

and yes just ate more cake, hate to be disrespectful and not eat : )
good day there
Floyd

[daddysgirl]

Hey Floyd.
I started with the schematics, and that's when I started to go crazy. Most of the bus wiring is where it belongs. However, when they put the new engine/auto transmission in in 2001, the mechanics in Fredricksburg didn't follow the schematics.
I have wires ( neutral relay...two places, for instance) that are either not connected to the NSS as in the schematic, or are not connected to stud 26. It was empty.
I'm not 100% sure when the starter stopped, after the mini fire last week, Logan was looking at the spark (he has since told me the spark did stop before I pulled the battery switch) and his attention focused on where to aim the fire extinguisher. Tomorrow, after I remove (hopefully) this stud block and give it a good cleaning, I'll know a bit more. I have removed and replaced every wire on the starter, and the cable going to power it, along with every single wire in the rear box...and all the relays.

But it is indeed the roughly 3-4' cable junction with 3 cables attached to it. It also has 4 screws, so I'm going to try to take it off.
I was thinking the same about the contact disc, but thus far, the rubber hammer has worked...twice. I didn't let it get hot today, so hopefully...

[brmax]

Ok
If the neutral safety is not working as designed~
I would disconnect battery power at main switch area 1st. Then recommend following up with removing the +battery cable at starter, bat+ solenoid connection stud.

This should keep everyone safe from vehicle starting "while" a safe checking procedure on the solenoid start/signal wire is conducted and repaired.

I have found a test light vise gripped to ground and the alligator part clipped to solenoid signal post work well if I see it. So with your helper the light can be checked in short order with in and out of gear switch signal confirmations.
As you mentioned a schematic and neutral safety wires were not likely replaced in prior work, as designed and so need traced.
Pretty straight repair, but tedious finding and connecting the neutral safety switch wires for sure. (no hill for a stepper)

Have a good weekend
Floyd

[luvrbus]

You need to be sure the installer didn't use a neutral switch at the shift tower and left the one on the transmission unhooked

[daddysgirl]

The only wire connected to the shifter is a wire for a light that burnt out long ago. The neutral safety switch has 2 wires. For years, it has been connected with one wire to the starter solenoid nipple (start switch wire isn't there), and the other wire to stud 12 in rear box.
The starter cable (new one) goes to the + on the solenoid. The ground goes from the starter motor itself to frame. There is a jumper from the other solenoid nipple to the starter ground terminal. There is a stud that faces upwards, and a stud with a solid strap connected to it. Neither of those is connected to anything else.
I cleaned up the rear box and made a new harness for the alternator, starter and all new battery cables. Now that the starter is getting the voltage required (and once I get the grime off the junction stud and transmission and look at those other cables) Can I disconnect both NSS wires and try to start it? Even if in a different gear, as long as I'm holding the brakes on? I think one of those big cables has bare copper touching the frame.

If I accidentally switched the NSS wires when I reconnected them, would that cause sparks? I am 99.9999% sure I didn't, but anything is possible. Also, every schematic has those 2 NSS wires going to the neutral relay and different studs then to ground. When I connected them as the schematic dictated...nothing. I can't see where the NSS is connected to ground?

The wire coming from the relay that is supposed to be connected to the neutral safety switch is cut off, and the top right wire from that relay WAS connected to the starter relay directly. It is supposed to go to stud 26, from there to the starter relay (71S) and from 71S to the starter solenoid. I connected that wire, but it didn't matter.

BUT...when I moved the stop cylinder on the governor, (maybe a hair) off the lever, even though the lever didn't move, the starter began trying to start.

I also wanted to tell you all how much I appreciate your help. I know in my gut this is something I can fix...but all of you know how maddening it is when ONE FREAKING wire is wrong. And the feedback you all give me makes me consider things I wouldn't have otherwise...so thanks!

[daddysgirl]

And the hits just keep on...

There are three harnesses that connect to the motor compartment stud. My new starter cable, the 4/0 from the battery switch and a 1/0 that connects to the rear junction box stud.

I went out to disconnect them so I could remove and clean the motor stud. New starter cable...no problem.
the 1/0 that goes to the rear box? Oh, my god. The terminal end is GONE. All that remains is the base, and it was melted to the washer. If the 4/0 that goes to the battery switch is OK, I can replace and reroute the 1/0. Well, at least I know where the sparks came from.

If I can figure out how to post a picture from my phone, I'll show ya.

[brmax]

Just somemore forward checking the start solenoid wire is momentary as suppose to be.
good luck there

[daddysgirl]

The starter doesn't stop when I let off the button.
I'm calling the shop and tow tomorrow.I'm not going to risk any serious damage, and I'm not strong enough to replace the starter. I know my limits, and I'm there.

[Rick 74 MC-8]

If you remove the small wire on the starter solenoid( not the small ground) turn the power back on. If it still crank's the Bendix is stuck if not it's in your wiring. I had a rebuilt starter in mine the fork to the Bendix came apart.  it held the solenoid from engaging the Bendix drive to the starter but I suppose it could stick the other way also.

[gumpy]

The only wire connected to the shifter is a wire for a light that burnt out long ago. The neutral safety switch has 2 wires. For years, it has been connected with one wire to the starter solenoid nipple (start switch wire isn't there), and the other wire to stud 12 in rear box.

Stud 12 in the rear j-box is supposed to go to the Front/Rear switch in the rear control panel. It then goes to studs 15 and 26 respectively, and then to the starter solenoid relay.
On the automatic transmission, 15 goes through the neutral relay contact and then to the starter solenoid relay. There are some minor differences based on the bus serial number. 

Seems like yours may be bypassed the rear control panel based your description, and maybe you don't have the neutral relay?

The starter cable (new one) goes to the + on the solenoid. The ground goes from the starter motor itself to frame. There is a jumper from the other solenoid nipple to the starter ground terminal. There is a stud that faces upwards, and a stud with a solid strap connected to it. Neither of those is connected to anything else.

The cable and ground seem correct. The jumper should be an L-shaped jumper that goes from the solenoid to the stud facing up on the starter motor. This is how power gets to the motor. The commutator in the solenoid shunts power to the motor when you activate the solenoid. The solenoid also engages the starter drive into the flywheel.

I think one of those big cables has bare copper touching the frame.

I'm pretty sure you'd know if one of those cables has bare copper touching the frame. Those cables should be direct from the batteries. The frame is grounded.

If I accidentally switched the NSS wires when I reconnected them, would that cause sparks? I am 99.9999% sure I didn't, but anything is possible. Also, every schematic has those 2 NSS wires going to the neutral relay and different studs then to ground. When I connected them as the schematic dictated...nothing. I can't see where the NSS is connected to ground?

No sparks. The neutral safety switch is simply switching the ground for the neutral relay. If yours is going from NSS to starter solenoid, then someone may have eliminated the neutral relay.

From your description, it seems like someone has eliminated the neutral relay and changed the NSS to switch the starter hot wire to the starter solenoid hot terminal. You said the other stud on the solenoid was jumpered to the negative terminal on starter motor. That would work. It bypasses some safety circuits, but it would work.

BUT...when I moved the stop cylinder on the governor, (maybe a hair) off the lever, even though the lever didn't move, the starter began trying to start.

Impossible. The stop cylinder is a pneumatic piston. Moving the air piston cannot make an electrical connection to the starter.


What is the serial number of your bus?

[gumpy]

And the hits just keep on...

There are three harnesses that connect to the motor compartment stud. My new starter cable, the 4/0 from the battery switch and a 1/0 that connects to the rear junction box stud.

I went out to disconnect them so I could remove and clean the motor stud. New starter cable...no problem.
the 1/0 that goes to the rear box? Oh, my god. The terminal end is GONE. All that remains is the base, and it was melted to the washer. If the 4/0 that goes to the battery switch is OK, I can replace and reroute the 1/0. Well, at least I know where the sparks came from.

If I can figure out how to post a picture from my phone, I'll show ya.

That's the wire that charges your battery from the alternator. Possibly you cracked or broke it when you replaced your starter cable, or you forgot to reattach it, and it grounded to the frame.

[daddysgirl]

The 1/0 cable that goes from the rear stud to the rear junction box stud MELTED. The 4/0 cable from the battery still has it's end.
The starter cable is OK, and yes, it was connected.

I've got a neutral relay, but it's not (never was) connected as it should be.

From what I can tell, the mechanic who installed the new engine and automatic tranny in 2001 used the wires on the neutral safety switch as starter wires.

Stud 26 was empty, 12-15 were/are not. I connected 29S from relay position 3 to 26 per the schematic up to 71S on the starter relay, then over. Nothing happened. 29S was going from position 3 directly to the starter relay.
The fast idle side relay contacts (6,7,8) are all connected as shown on the schematic, as is the field relay.

I am aware of the stop lever cylinder. I was just repeating what I did and what happened when I did it. Better chance the electric cylinder that shuts off the air finally opened.

The serial # is 8FV2553
Model # is 7087-7527 (Customer specified)
The unit # is 30048 September 1973

[daddysgirl]

BTW Craig...
When you reference the "L shaped jumper" is that a wire or a copper strap?
I only ask because the only connections that have ever been made between the motor and solenoid are:

the power line to the solenoid
Little jumper between solenoid and motor ground
motor ground to frame stud
NSS to switch nipple on solenoid

From what I can see, there is nothing on the stud facing up, unless the strap is going to the "up" stud. I can't see that in detail the way the starter is mounted. And these are the only connections that have ever been there. 16 years...same thing. The ONLY thing I did on the starter is change the cable to positive stud on the solenoid and the cable to ground on the end of the motor (After a test directed by MCI tech, I didn't remove a wire and burnt up the starter cables...see earlier post). And thanks for your help. I'm not trying to be argumentative...just typing what is actually there.

[gumpy]

BTW Craig...
When you reference the "L shaped jumper" is that a wire or a copper strap?
I only ask because the only connections that have ever been made between the motor and solenoid are:

the power line to the solenoid
Little jumper between solenoid and motor ground
motor ground to frame stud
NSS to switch nipple on solenoid

From what I can see, there is nothing on the stud facing up, unless the strap is going to the "up" stud. I can't see that in detail the way the starter is mounted. And these are the only connections that have ever been there. 16 years...same thing. The ONLY thing I did on the starter is change the cable to positive stud on the solenoid and the cable to ground on the end of the motor (After a test directed by MCI tech, I didn't remove a wire and burnt up the starter cables...see earlier post). And thanks for your help. I'm not trying to be argumentative...just typing what is actually there.

The strap has to be going to the upward pointing stud on the starter motor. If it weren't the starter motor would not turn at all. That strap is a solid metal strap, shaped kind of like an "L" with a 90° bend in it. It connects the left stud of the solenoid to the starter motor (as you look at if from the rear of the bus).

Looking at it from the rear, the solenoid is slightly offset towards the right. There are two large studs. The positive battery cable is connected to the lower one (right most), and the strap is connected to the upper one (left most) and connects the solenoid to the motor. This is what gives the motor power to turn. That motor stud comes up from the motor basically right in between the two solenoid studs. Then, the solenoid has two small terminals. The right one (lower most) is the positive, which ultimately comes from your start button. The left one is the negative for the solenoid coil. Mine has a jumper to the negative stud on the end of the starter motor. There is also a wire that goes back into the wiring harness. Not sure what that one is.

I'm beginning to believe that your starter solenoid is stuck in the on position. It's pretty easy to test that. Use an ohm meter to measure resistance from the positive battery cable terminal to the jumper terminal. If you have continuity, then the commutator is stuck in the on position, which would allow the starter to turn as soon as the batteries are turned on.

I'm still very concerned about the melted cable, though. That doesn't make sense. One cable inside a stack of three is not going to melt unless it was either cracked or loose.

As for the wiring of the neutral solenoid, there are two diagrams in the manual you need to look at. One is the standard motor control wiring and the other is the automatic transmission wiring for you model number. The transmission one shows 29S going directly to the starter solenoid relay. The master schematic shows it going to stud 26. If stud 26 is empty, then it's following the transmission wiring, which should be just fine. However, it seems your bus has the neutral switch routing the positive start signal directly to the starter solenoid, rather than the ground to the neutral relay. Either will work, as long as you understand what has been changed and don't try to change it back without fixing the entire circuit.