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Author Topic: Bus starting problem  (Read 2932 times)
jjrbus
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« on: August 05, 2008, 10:33:14 AM »

I'm reading about Chaz's misadventures and thinking how lucky I have been. Since 2000 I have had 4 stoppers!  The first was brand new alternator belts snapping, the First time I drove the bus!!!! If all is to be belived, MCI had distributed defective belts. I have not had a problem with them since.
 The second time was right in the middle of a huge busy intersection, the bus died. I pressed the start button and it fired up and no problem like it since.
 The next two were on the same trip, and I can not blame them on the bus. The first was alge blocked the fuel lines. Right in the middle of a street. It was a small suburban cul de sac and nobody complained. Frustrating but not that big a deal. The second I noticed the temp going up, pulled into a rest area, into a spot and the hot engine sensor shut it down. The bus God's were smileing on me.  On my pre trip I had looked at the sight glass and what I saw was dirt, not water!!! All in all I cannot complaine.
 Over the years after the bus sits for a while, when I pust the start button, I can hear the soliniod almost engage. After I push the start button 2 to 3 time it engages and the bus fires almost instantly. One of my bus hero's Jack, diagnosed it as surface rust building up inside the solinoid and cause it to hang up a bit. A couple try's on the start button and it cleans the rust off. This has been happening for several years.
 Now I have two new ones, I left Largo FL and am heading to Ft Myers. I pull into a rest area for lunch. I shut the bus off. I seldom shut the bus off.  I go to restart it and it just turns over. Nothing!! Oh No!!!  My bus starts instantly every time, Since 2000 I have never heard the engin turn over it just starts.  I push the button again, it turns over but does not start.  I am in a rest area, but still this is not good.  I push the button a third time and it starts instantly!!! Whew, but now I am afraid to turn it off.. I do not like these kinds of problems, either brake and get fixed or leave me alone!!!!
 I am trying to get into my site in N Ft Myers and I swear the brakes are hanging up. I've been in this site befor and the dirt is soft. But this does not feel right!!  Is it the dirt or the brakes? Guess I will have t figure it out.
 So any suggestions on where to begin on the starting or the brakes.
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JackConrad
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« Reply #1 on: August 05, 2008, 11:23:51 AM »

Jim,
  Very difficult to diagnose a problem when it is not happening. When you tried to start the bus, did you notice any white smoke coming out the exhaust?  Sounds like no fuel to the injectors. A couple quick thoughts.
   Maybe the engine stop solenoid stuck, not releasing the air to the engine stop piston on top of the govenor. This could be a mechanical or electrical issue preventing the solenoid from functioning properly.  If this occurs again, go to the engine and look at the engine stop piston on top of the govenor. With master switch on, piston should be retracted into the cylinder with no pressure on fuel shutoff lever.
   Another possibility is that your fuel return line check valve is stuck open, allowing the fuel line to drain down.
    As far as the brakes, it could be the soft dirt.  We have had  mucho rain the last couple weeks (little over 2" yesterday afternoon).  Might want to do a preliminary test on a paved surface. If they still seem to be dragging, AFTER BLOCKING BUS, make sure they are properly adjusted. After adjusting the brakes, watch the brake linings from under the bus as Josephine makes a hard application. Brake linings should apply and completely release when brake pedal is released. Jack
PS: "Mom" said to tell Josephine HI
« Last Edit: August 05, 2008, 11:27:43 AM by JackConrad » Logged

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jjrbus
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« Reply #2 on: August 05, 2008, 12:05:10 PM »

Thanks Jack, I did not look for smoke and I only held the button down a couple seconds.   I was thinking (oh oh) on the brakes. For some reason I suspect the rear bakes. I was thimking I could jack up one side at a time and see if I could spin the wheel. But your idea seems much eaiser!!  Even though I do have a nice 12 ton air over hydraulic I like to play with.
                                                                   Jim
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« Reply #3 on: August 05, 2008, 12:12:32 PM »

If you jack up one side. don't forget to chock the other side and release the parking brake. Reminds me of the time I tried to adjust the drive axle brakes--forgot to air up and release the parking brakes DUH!!  Jack
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« Reply #4 on: August 05, 2008, 12:21:39 PM »

One trick that I have used to check the brakes to see if they are draging is to let the truck in this case the bus come to a complete stop on it's own.  Or stop and then let it roll a little.  If the brakes are draging you can feel bus com to a stop sooner than it could have.  If they are now draging you might even feel the bus roll back wards after coming to a complete stop if it is a little up hill grade where you are.  If the brakes are draging you can tell the difference if you pay real close attention.
This will work with any vehicle, I do it with all of mine from time to time when I am concerned about the brakes draging.
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« Reply #5 on: August 05, 2008, 03:48:02 PM »

I cant figure a way to make this as interesting as Gumpys thread. But will go on anyway. I changed over to the rear start to be able to obsearve, did you know the master switch has to be on to do this? I did not, or if I ever did know it, I forgot.
 When I pushed the rear start button, the starter engaged, barely moving the engine, made a horrible sound and then just spun. I am going to assume I have either a siezed up engine or a bad selenoid. Reading the service manual it seems that there are two windings in the solenoid, one should be bad. Not having the skills alot of you have I will try to find a starter/alternator shop in the Ft Myers area. failing that I will Huh?
 Now you can win 3 points, by perdicting what I will do next!! No psychics allowed.
 
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« Reply #6 on: August 05, 2008, 04:39:36 PM »

Might be the starter Bendix.  There is a large truck parts place in Billy Creek Industrial Park . This is the road that goes to Camping World. It is on the right as you make the last curve before Camping World.  I think the name of the Place is Jack Lyons.  Be careful when taking that last bolt out of the starter, it is very heavy. If you have a small floor jack, that is a good thing to lower the started.  You may need a 12 point socket for the starter bolts, sometimes thay use a special 12 point headed bolt.  Jack
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« Reply #7 on: August 05, 2008, 04:42:16 PM »

jj,

Electrical things do funny things when hot. The starter spinning tells me the solenoid is probably not getting enough power to keep it engaged.

My first guess is the starter relay, not the solenoid, but it could be the solenoid.

Start by cleaning all the contacts on the relay. If cleaning doesn't help try jumping around the relay. If that works the relay is bad.

If that doesn't help, then clean all the contacts on the solenoid. If that doesn't help jump around the solenoid directly to the starter. Watch out for big sparks when you do this!! The quicker you connect the jumper the less fireworks.

If that doesn't help clean all your large battery cables from the battery posts on back to the starter.

Battery posts slowly develop a slight dark colored corrosion layer over time and this reduces power available. They should be shiny and also the inside of the battery clamps do the same thing if they are lead coated.
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jjrbus
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« Reply #8 on: August 05, 2008, 05:51:11 PM »

 If the relay is bad, would the solenoid try to engage?   I remember Lyons, Jerry and I went there together!
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« Reply #9 on: August 05, 2008, 06:05:07 PM »

Jim if you need anything like tools or help in any way, feel free to contact me. I will be available tomorrow after 12 and can make the trip to where you are. I have a short job to do in the morning but will be free. I guess I'm about 3-4 hours from you if that helps!
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Ace
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« Reply #10 on: August 05, 2008, 09:32:28 PM »

ace, everybody but susan tells me what a nice guy, and helpfull you are.  you've just provin it again.  tell susan to go practice her bluegrass and quit makin comments to fran about you.. Grin
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« Reply #11 on: August 05, 2008, 11:38:37 PM »

Ace...That is very nice of you to help. Spinning Jim may still need you or who ever is closer for extra hands to do this and repair.

If I were there to witness & diagnose your problem, I can find your problem. For not being there I will try to give you step by step and hope I didn't miss any. Let us know what you're finding. Am not surprise it something else that not been reported.

Here are few steps to diagnoses starter & solenoid & bendix & relay before solenoid & NC (normal close) fuel pressure switch problem: Please use an analog meter only…so you can watch needle to be steady or erratically like a loose connection or dirty relay's points for diagnostic reason. Alligator clip on both test leads to get a good sable connection. Set meter range at 30 volt DC or the next higher scale.

Before the tests, the batteries should be at 80% or higher state of charge for diagnostic checks but not cranking voltage test unless full state of charge.

I attached a wiring circuit with numbers which label each test points.

A) NC fuel pressure switch:
1) Hook + test lead to #7 and – test lead to #8…while cranking, it should read 0 voltage until it starts.. If it erratically or full battery voltage before engine run…bad pressure switch. Hook up + test lead to #8 and – test lead to chassis GRD… it should read 0 voltage until it starts. If it erratically or full battery voltage before engine run…poor ground wire or connection.
2) If fuel pressure is higher then 8 psi @ cranking speed…checks for restricted return fuel line flow. It will cause the starter to shut down automatically.

B) Starter switch relay before solenoid:
1) Hook up analog meter + test lead to #6 and – test lead to chassis ground…it should be at battery voltage while cranking. Otherwise if it erratically meter movement….bad starter button switch or wire connection.
2) Hookup analog meter to solenoid coil post (#5) (it the same + from battery post) with + lead and – lead to (#4) pressure switch. Watch voltage meter for steady cranking voltage reading while hold down the start switch…if it 0 voltage while cranking is good. If it does erratically while using either front or rear starter switch mean bad wire connection to or in the relay or bad relay points.

C) Solenoid:
Hookup analog volt meter with + test lead to + post (#1) of solenoid and – test lead to starter's + post (#2). Watch for meter goes to 0 voltage while cranking…that is good. But if it erratically…bad connection either in solenoid's contact switch or starter's brushes or wire connection. Take it to repair shop for further testing or replace both solenoid & starter motor with warranties.

D) Bendix Drive:
1) Wrinnninnnn noise (spinning) mean over run clutch is slipping, mean a bad bendix drive.
2) Very loud gear clashing before fully engage…either worn gear's teeth    or    starter is spinning before fully engage…solenoid connecting link is out of adjustment or worn out. Replace both solenoid & starter motor with warranties.

E) Starter Motor:
Hookup analog or digital volt meter to solenoid's + post (#1) and the – lead to engine's ground. Watch for voltage dropping at the beginning & during cranking.  If the voltage is below 18v with a fully charged 24v system and growling noise mean starter bearing is worn out to cause armature to rub on field poles. Replace both solenoid & starter motor with warranties. If no growling noise…check power source for weak & “hot” (high resistance) connection of both the + positive & - negative. While cranking with fuel shut off, it should never have more then .5 volt drop between #1 and starting battery's + post. Same way with grounding between engine to battery – post of no more then .5 drop. Under size wire or cable will cause greater voltage drop as well old cable with a few broken strands from too much vibrating and/or corroding.


Whatever you do about getting parts replacement, always take the old one with you to the store same or newer version.

FWIW

Sojourn for Christ, Jerry
« Last Edit: August 10, 2008, 06:27:09 AM by Sojourner » Logged
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« Reply #12 on: August 06, 2008, 06:09:01 AM »

If the relay is bad, would the solenoid try to engage?   I remember Lyons, Jerry and I went there together!
No, if the starter is trying to do anything, the realy is not the problem. Does the starter spin fast?  What is the voltage at the batteries when the starter is engaged? Would you like us to come down and help. I know Paula would like to visit with her "daughter". We can come down today or Friday. I have a Dr. appointment tomorrow.  Just give me a call.  Jack
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« Reply #13 on: August 06, 2008, 06:57:17 AM »

What great guys !!!

Although, I cannot offer to make the 1200 mile trip, I would like to add a comment.

Whether you are stuck along side the road, or trying to figure something out at home, there is value in additional inputs.   One, it gives you time to think more clearly.  Also, "Brainstorming" of various options is helpful.  I was always surprised to get excellent ideas - some of them used - by my kids who were 14ish at the time.

In this case, I would expect the analysis to have identified the problem.

Ed Roelle
Flint, MI

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« Reply #14 on: August 06, 2008, 02:14:05 PM »

Jack,

I don't completely agree with you because sometimes the start relay will not pass enough voltage/amps to the solenoid to either engage it or hold it because of burned/corroded connections or termianls or just a weak coil.

This relay is very often the cause of starting problems. If it doesn't work properly nothing else to the starter will either.

A spinning starter means the solenoid is either not engaging the starter motor gear to the flywheel or is not holding it there.

It could be anything between the relay and the starter solenoid. It could even be the starter switch at the panell.  Jumping the relay will quickly show if the relay or switch is the problem. There was a string just recently in which the starter switch failed. As I remember all the starter switch does is ground the start relay.
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