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Author Topic: starter was turnig real slow and now just clicks  (Read 5604 times)
Dlsnow
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« on: October 18, 2013, 06:50:35 AM »

I seem to have one post per day.  This one boggles my mind.

I am in Amarillo, TX

I went to start the bus this morning and it turned real slow.  Sounded like I had dead batteries.  So I check the batteries and they are each at 12.6v.  I went to start it again and it turned slow then stopped.  Now when I try to start it it just clicks (like a solenoid click not the starter).

FYI - I was starting in the engine bay with the rear start switch.

Good morning busnuts
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1972 MCI7 8v71 converted - 1kw solar on roof
Ed Hackenbruch
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« Reply #1 on: October 18, 2013, 06:59:01 AM »

Probably the first thing to do is to clean the ends of the cables and the battery posts, even if they look ok there might be enough tarnish/corrosion on them to keep the starter from getting enough juice.
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1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
muldoonman
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« Reply #2 on: October 18, 2013, 07:02:01 AM »

Had something happen like that on my 91 8V92TA and about same voltage last year. Checked all cables. Finally pulled cables off 31's battery posts and cleaned and put charger on batteries to get up to high 12 volts and it cranked as normal. I think mine was a little corrosion under battery posts. Hope you get er fixed.
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OneLapper
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« Reply #3 on: October 18, 2013, 07:06:19 AM »

Good morning to you, too!  


Ok, here's the quick run down.  Use your house batteries to assist the start batteries. If it cranks with authority the starts have a shorted cell or some other issue. If it doesn't start the starter is suspect or the cable to the started has high resistance.  

Good luck.  Sending you good karma.  

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OneLapper
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Dlsnow
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« Reply #4 on: October 18, 2013, 07:33:11 AM »

I am scarfing down breakfast then jumping into my ccoveralls.  Maybe one day I will get this engine bay steam cleaned. 

Thanks for the help

I see the two large cables going to the starter terminals and there are also two smaller (12awg maybe) cables.  What are the smaller ones?  It looks like the PO used a small vice to clamp the one off the negative terminal to the chassis.  I'll bet this has something to do with my issue.
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1972 MCI7 8v71 converted - 1kw solar on roof
Lin
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« Reply #5 on: October 18, 2013, 08:43:07 AM »

Quick review-- Merely because the battery terminals do not look bad does not mean they are making good contact.  Remove them, clean well enough to make sure the oxidation on the terminals and post is gone, and replace them.  Make sure all the cable connections from the batteries to the starter and chassis are clean and tight.  Even if that doesn't work, it's a good preventative maintenance chore anyway. It would be good to charge the batteries if you can and test them with a hydrometer to see if you have bad cells.  Remember, the hydrometer needs a fully charged battery to give you an accurate reading.  Battery voltage can test well but if there are bad cells, they may not work.  Next, try jumping from the house or car batteries.  If there is no difference then you are heading into a deeper issue like the starter, but it does not sound like that.  And yes, if any ground you have is only held on by a clamp, bolt it in.
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RickB
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« Reply #6 on: October 18, 2013, 09:19:54 AM »

Disnow,

This coupled with your other post about black smoke makes me wonder if you don't have something else besides cables here. Low power, black smoke could be related to your blower and the seals inside of it and there a number of major engine issues that could keep the motor from turning freely, including the blower, the power steering pump, the alternator etc.. There are others here that know alot more than I do but I believe these issues could be related. I've done the cleaning cables/grounds thing and it isn't fun, battery powered drill at high speed with a wire brush and they sell a terminal sealant that will help keep it from happening. Make no mistake about it this is a dirty job.

Remember to disconnect your battery at the front main disconnect and according to the instructions if you have a vanner equalizer before you remove the grounds in the engine compartment or you'll end up doing some unintended welding!!

Good luck and let us know what you find out

RB
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luvrbus
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« Reply #7 on: October 18, 2013, 10:04:28 AM »

Time to changes the brushes in the starter IMO
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Lin
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« Reply #8 on: October 18, 2013, 10:24:11 AM »

RB- Make sure that if you use those terminal sealer sprays you apply it after everything is hooked up and tightened.
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Dlsnow
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« Reply #9 on: October 18, 2013, 10:35:59 AM »

So far here is what I have done and have figured out.

I cleaned all exposed terminals and connections on the starter.  Used carb cleaner on metal elements and a wire brush to ensure solid connections.  I also followed the ground leads (two of them) and cleaned and brushed the connection to chassis.  I tapped and permanently affixed the clamped ground to the chassis.

Same thing...loud click (like a solenoid) and no turning it doesn't sound like the starter even tries to go.  

I opened the electrical panel on the left side of the engine and located the relay that was clicking.

It has two larger leads off the left and right and two in the front of it (front left and front right).

Here are the volt readings for when the start switch is off and on.

Switch off
L 0v
Fl 0v
Fr 0v
R 25.9v

Switch on
L 25v
Fl 25v
Fr 41mv (millivolts)
R 25v

I am going to see if I can get a reading on the starter with the switch in the same place.
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1972 MCI7 8v71 converted - 1kw solar on roof
luvrbus
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« Reply #10 on: October 18, 2013, 10:39:09 AM »

Disconnect the fuel pressure switch and give it a try
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John316
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« Reply #11 on: October 18, 2013, 10:46:54 AM »

I bypassed the other switches, and mounted a momentary on switch right on the starter. That way, no matter what, if I had juice I could spin the starter. I love that mod....
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MCI 1995 DL3. DD S60 with a Allison B500.
Dlsnow
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« Reply #12 on: October 18, 2013, 10:48:00 AM »

I measured the voltage at the starter terminal.

It is at 24v when the switch is pressed and at 0 with the switch off.

Should I still check the fuel pressure switch?  I will need some guidance locating it if so.

Why does it always have to be cold outside when I need to work on the bus?  Lol
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1972 MCI7 8v71 converted - 1kw solar on roof
Dlsnow
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« Reply #13 on: October 18, 2013, 11:10:46 AM »

Reading maintenance manual it describes the starter solenoid that pushes the starter gear into the flywheel mesh closes the circuit that energizes the starter.

I am going to go measure the voltage at the solenoid to see if that is getting voltage.
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1972 MCI7 8v71 converted - 1kw solar on roof
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« Reply #14 on: October 18, 2013, 12:11:46 PM »

First thing is that if the solenoid is clicking it most likely isn't the fuel pressure switch.  The fuel pressure switch is on the secondary filter head and provides the path to ground for the starter solenoid.  If it clicks it has ground.  Second, the solenoid does two separate things.  The big click is it pushing the pinion out with a lever so that it can engage the flywheel.  That is done by energizing a big coil that is an electromagnet.  The other thing is does is it has a copper disc behind the two big wire terminals and it makes the connection between them when the coil is energized.  You can, if you are careful, bridge between those two terminals with a big screwdriver to momentarily spin the starter motor.  That will prove out the motor itself.  Be aware that it might try to weld itself and stick, so use a big screwdriver with leverage to take it off again once the starter spins for a second.  If the starter spins, you can undo the big wire connections and take the front of the solenoid off to expose the copper disc, and you will probably see it burnt.  You can clean it up or rotate it a bit so the spots that make the circuit are clean.  Luke told me this so it must be true (my problem turned out to be the fuel pressure switch when I had an issue so I didn't take my solenoid apart)

So step one, bridge the terminals to see if the motor spins, if it spins take the solenoid apart and see if you can clean up the connections inside.  If the motor doesn't spin, buy a new motor or get yours rebuilt.  You don't want to take the solenoid off if you can help it, just take the front off.  It's PITA to get the levers to work the pinion right, and I don't know if you could even do it with the starter mounted on the engine.

Hope this helps a bit.

Brian
« Last Edit: October 18, 2013, 12:16:25 PM by bevans6 » Logged

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