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Author Topic: Troubleshooting start problem  (Read 4245 times)
CraigC
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« Reply #15 on: August 15, 2008, 03:26:12 AM »

Do you know how to read the mfg. date code on the batteries. Before I did, I purchased some sealed batteries from a major retailer. I had nothing but problems with them and after 2 years went to a battery specilizity store. I found out they were 4 years old when I purchased them. A thru L is the month code and 08,07, 99  & etc are the year of mfg. many times a round white sticker on the side. I am not talking about the date code they punch out when the battery is put in service for warranty purposes.
I also agree the refracometer is a great tool for battery state of charge. will not work on the sealed batteries.
I reciently replaced field coils on a starter that would not start when the engine was hot. When cold it started every time. That cured my problem. Previously I replaced all cables, cleaned all contact points, and used star washers. The field coil in my system was the absolute last thing left for me to try. Everything else was new.
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« Reply #16 on: August 15, 2008, 06:34:32 AM »

Will putter with it again soon, I may jury rig the switch and see if I still have a starting problem.
Thanks for all the help  Jim

Jim,
  If your fuel switch is wired like our MC-8, all the switch does is complete the circuit to ground until you have fuel pressure. Simply grounding the wire coming from the starter relay. Connecting the 2 wires that were on the switch will work, as long as the wire going to the frame has a good ground connection.  If the bus starts normally, you found your problem.  Jack
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« Reply #17 on: August 15, 2008, 07:29:44 AM »

8 and 5 must be different there is only one wire on it! I doubt that this was the problem. It was corroded and I decided to clean it, shuda left it alone. On the birght side a new one is onl $31 and a week away.   Jim
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« Reply #18 on: August 15, 2008, 07:41:40 AM »

Jim,
   It is probably grounded through the switch. Check the wiring schematic.  With the wire disconnected, try the starter-should get absolutely nothing (no click, nada).  Then connect the wire to a good ground, try the starter-engine should spin over.  If not you have another problem.  Jack
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« Reply #19 on: August 15, 2008, 01:34:50 PM »

Thank you very much for all your tolerence, input and suggestions.  It appears on the surface to be a battery. These batteries (2 group 31"s) were originally purchased new 11/07 taken back twice for load tests and one was replace 04/08, I took them yesterday for the third load test, the newer battery showed recharge and retest which I refused, they replaced it under warrenty. 
 I reinstalled the batteries today touched the button and it fired right up like it normally does!! Hopefully this is the end of it.
                              Many thanks Jim
 
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« Reply #20 on: August 17, 2008, 02:24:50 PM »

Replaced batterie and busfires right up!!!! problem solved!!   Try it next day and if fizzles, selonoid just whirrrrs!  Push button again,  it starts.  No sense trying to go any farther everything is warm.  Get out the analog tester today, hook up, push button and it fires instantly, go figure?? 
 I really hate intermittent problems.
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« Reply #21 on: August 17, 2008, 02:34:02 PM »

Sounds like a loose wire or a bad ground someplace.

I dunno.

FWIW,

Paul
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« Reply #22 on: August 17, 2008, 02:41:37 PM »

Sounds like a loose wire or a bad ground someplace.
Paul

or a corroded contact in a relay/switch,solenoid.  Jack.
PS: any difference when using front or rear start switch?
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« Reply #23 on: August 17, 2008, 03:51:09 PM »

No difference in front and rear switch.  Does seem like dirty, corroded, loose contact somewhere. I do not belive that Jerrys diagnostics will work well with intermitent problem? Plus can only do one connection at a time as once heated it is no longer a bad connection?
 I am thinking (oh oh) of takeing starter in for PM. That would leave only relay or bad connection/wire to trace down.
                          Jim
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« Reply #24 on: August 17, 2008, 03:59:14 PM »

No difference in front and rear switch.                            Jim

That pretty well narrows it down to the starter relay, starter solenoid, fuel pressure switch, and the wires/connectors between these.  Bring you wiring schematic with you tomorrow when ya'll come up for supper.  Jack
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« Reply #25 on: August 17, 2008, 04:34:21 PM »

I am @$# u me ing  that becuse the starter is attempting to start, ie the bendix is wrinnnninnnnn spinning. That the fuel pressure switch is good Huh
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« Reply #26 on: August 17, 2008, 04:49:28 PM »

I agree with Jack, if both starter switches give the same results that eliminates them and the wiring to the starter relay.

I still suspect the relay since it seems to give the most trouble. Next time you try to start it and it fails try jumping around the start relay. Of course this may prove nothing but the relay can be checked with a voltmeter after disconnecting the relay from the starter solenoid. With the voltmeter connected to the solenoid wire connection on the start relay have someone hit a start switch a number of times since it is intermittent.

If the voltage is full and constant each time this probably narrows it down to the wiring to the solenoid, the solenoid or the starter.

I woudn't remove the starter until you have isolated the problem definitely to it. It is a heavy, messy job and you will hate yourself if it is ok.
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« Reply #27 on: August 17, 2008, 08:34:24 PM »

I got an idea.  Attach a push button switch  between a B+ source and the "S" terminal on the engine starter solenoid.   Use enough wire to locate the switch in a convenient place to access.
Turn on the ignition, go the the switch and start the bus.  If it continues to start with the "remote" starter button, the problem is in the chassis wiring or slave solenoid (not the starter solenoid), if it 'fizzles' after a couple of starts, the problem is either the starter battery leads, dedicated starter ground, or the starter solenoid, or starter motor. 
You could rule out all of the secondary wiring and relays this way. 
Auto stores may still sell remote starter buttons.  They were common some years ago for turning engines over.   Had a push button and two alligator clips with about 4' of wires.
The "S" terminal on the starter solenoid is the small terminal. 

JR
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JR Lynch , Charlotte, NC
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« Reply #28 on: August 18, 2008, 12:39:01 AM »

Spinning Jim....Did you keep the fuel injector in "off" mode while crank testing? If not, you will not get the information you needed because if it starts before the testing result can be attained. This has been mention in the following link: http://www.busconversions.com/bbs/index.php?topic=9118.0

Cranking without starting will give you all the electrical starting and battery wiring under the worst strain load to show where the problem is. Then follow the process of elimination steps.

However, now that you mention the “solenoid (you may mean the starter) just whirrrrs!”…sound like starter spinning but bendix’s clutch is bad. That can be an intermitting problem….sometime it spin engine over and other times it doesn’t. That diagnostic step “D” of this post: http://www.busconversions.com/bbs/index.php?topic=9118.0
Try this several cold push button starting with fuel injector in “off” mode and until you hear it whirrs or not cranking the engine.


About bendix drive’s clutch. It has a one-way direction clutch so after the engine is started…it keep the starter from over spinning to avoid damaging to starter motor and help disengage freely from flywheel ring gear. They do wear out….or hang-up via clutch disc plate’s compound (manual transmission) inside the bendix’s clutch to dry its lubricant. If anyone has this problem…dip bendix drive in brake fluid to lube and avoid hang-up. Been there and done that on a fleet of mobile home trailer haulers and eliminate redundancy R&R job.

BTW…not all bad bendix drive will show bad while it removed from engine via hand rotating its bendix’s gear to see if it will rotate freely or stiff either way without armature turning.

Hope you find your lovely intermitting problem before it gets you in the greater spinning mode. LOL (I wouldn't like it either)

Jim!!!...call me eight six three six three three eight nine seven nine…please…anytime.

If you will, we can walk and I can hear whatever the whrrrii sound and report whatever the culprit later.

Sojourn for Christ, Jerry

PS...I am sorry Jim for you going through this a runaround problem.
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« Reply #29 on: August 18, 2008, 05:54:11 AM »

I am @$# u me ing  that because the starter is attempting to start, ie the bendix is wrinnnninnnnn spinning. That the fuel pressure switch is good Huh

    If the starter is spinning at a "normal" rpm, sounds like the starter. However, I would would thoroughly check everything else before trying to remove the big heavy starter.  I am not sure whether reduced power due to a poor connection/contact would allow starter to spin, but not provide enough power to engage bendix.  Using a heavy jumper to bypass starter relay is easier and quicker than removing starter. I usually try to "rule out" the easy simple things first, then move on to the more difficult such as removing the starter.  Jack
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