Author Topic: Pulsating lights  (Read 3316 times)

Offline akbusguy2000

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Pulsating lights
« on: April 19, 2008, 02:34:07 PM »
This isn't a new topic as it was discussed thoroughly back in November - see:

http://www.busconversions.com/bbs/index.php?topic=5471.0

I had experienced this with my 1963 gm4106 starting in June, and it only got worse.  Eventually the alternator began to work only intermittently, sometimes lighting up the "not gen" tell-tale, sometimes not.  But as I have a dashboard voltmeter, it was always obvious when it wasn't working, plus the tachometer which runs off the relay terminal would reflect the condition by its own erratic action.  For a while I could get it to work occasionally by putting a load on the system - turning on everything - but it finally quit entirely about halfway between Las Vegas and Twin Falls. 

So, the tests began - generator and regulator diodes, etc., and everything checked out OK.  But the problem turned out to be a bad (open) coil in the starter control and generator relay - rear electrical compartment.   I had little luck finding a replacement relay, but did find the ultimate fix at Coach Information Network in a well-thought out procedures manual to replace that part of the system with a magnetic switch.  It involved changing some wires around, mounting the magnetic switch, etc., - about an hour's job.

The results are that there is no more pulsing and the voltage stays rock steady at all rpms regardless of the load.  There is no waiting  for the generator to kick in either - its registering instantly and the tach even registers the rpm during the starting process. 

In the change-over the "not gen" light is removed from the system and there is no more starter interlock.  But the tach and the voltmeter always indicate that its working.  I don't need the starter interlock because my starter switch is keyed, and because the V730 has its own interlock to prevent starter engagement while in gear.

In a companion procedures manual, the generator sensing relay and the big resister that goes with it are also replaced by a magnetic switch.  The earlier 4106's did not have this particular relay.

This may not be of help to owners of other coaches - perhaps not even to other GM models, but it was the real ticket for mine.

tg


Offline Fred Mc

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Re: Pulsating lights
« Reply #1 on: April 19, 2008, 09:34:28 PM »
Can you tell me what manual you found the procedure in?

Thanks

Fred  Mc  PD4106

Offline akbusguy2000

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Re: Pulsating lights
« Reply #2 on: April 19, 2008, 11:26:50 PM »

Offline tekebird

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Re: Pulsating lights
« Reply #3 on: April 20, 2008, 04:55:28 AM »
another option is to get the new relay.

I have boxes of new GM relays, if you happen to have the part number

Offline akbusguy2000

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Re: Pulsating lights
« Reply #4 on: April 20, 2008, 08:53:59 AM »
Delco part # 1118522
I don't know the GM part number.

tg

Offline zubzub

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Re: Pulsating lights
« Reply #5 on: April 20, 2008, 09:17:05 AM »
I am having trouble trouble shooting my gen so I would like some clarification...at the begining of your post you mention your alternator, but later you refer to it as a generator.  Am I right that it is a generator, I know little of the 4106 set up but given when it was built I presume it is a generator. 
This isn't a new topic as it was discussed thoroughly back in November - see:

http://www.busconversions.com/bbs/index.php?topic=5471.0

I had experienced this with my 1963 gm4106 starting in June, and it only got worse.  Eventually the alternator began to work only intermittently, sometimes lighting up the "not gen" tell-tale, sometimes not.  But as I have a dashboard voltmeter, it was always obvious when it wasn't working, plus the tachometer which runs off the relay terminal would reflect the condition by its own erratic action.  For a while I could get it to work occasionally by putting a load on the system - turning on everything - but it finally quit entirely about halfway between Las Vegas and Twin Falls. 

So, the tests began - generator and regulator diodes, etc., and everything checked out OK.  But the problem turned out to be a bad (open) coil in the starter control and generator relay - rear electrical compartment.   I had little luck finding a replacement relay, but did find the ultimate fix at Coach Information Network in a well-thought out procedures manual to replace that part of the system with a magnetic switch.  It involved changing some wires around, mounting the magnetic switch, etc., - about an hour's job.

The results are that there is no more pulsing and the voltage stays rock steady at all rpms regardless of the load.  There is no waiting  for the generator to kick in either - its registering instantly and the tach even registers the rpm during the starting process. 

In the change-over the "not gen" light is removed from the system and there is no more starter interlock.  But the tach and the voltmeter always indicate that its working.  I don't need the starter interlock because my starter switch is keyed, and because the V730 has its own interlock to prevent starter engagement while in gear.

In a companion procedures manual, the generator sensing relay and the big resister that goes with it are also replaced by a magnetic switch.  The earlier 4106's did not have this particular relay.

This may not be of help to owners of other coaches - perhaps not even to other GM models, but it was the real ticket for mine.

tg


I am having trouble trouble shooting my gen so I would like some clarification...at the begining of your post you mention your alternator, but later you refer to it as a generator.
 1.Am I right that it is a generator, I know little of the 4106 set up but given when it was built I presume it is a generator.
2. Also is the relay you are talking about in the general compartment area or in the actual voltage regulator.... I dislike gens but mine is rebuilt so I'm hoping I have a simple relay problem as the only thing I like fooling with less than gens is VRs for gens...
If anyone else can chime in about the possible similarities between 4104 and 4106 gen/wiring/relay set
ups, I'm all ears.
3. and finally Delco part # 1118522 is that a relay or the magnetic switch.

Offline Fred Mc

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Re: Pulsating lights
« Reply #6 on: April 21, 2008, 05:53:42 PM »
Tekebird, are you saying that you can solve the problem simply by replacing the relay.

How much are they?

Thanks

Fred Mc.
PD4106

Offline akbusguy2000

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Re: Pulsating lights
« Reply #7 on: April 22, 2008, 09:55:50 AM »
ZubZub:  You are correct - the unit is referred to in the manual as a "Generator."  However, I believe it is in fact an alternator with a built-in diode/rectifier package enabling it to produce DC current.  Its the big oil cooled, mechanically driven 220 amp unit commonly found on the 8V71.

The regulator is a separate unit mounted in the starting battery compartment.

The Delco relay #1115822 is mounted in the rear electrical compartment (on a 4106)



FredMc:

I spent weeks searching for a replacement for the delco 1115822 relay and only found one in "used, as-is" condition in Georgia.  I won't give you the asking price, but the individual tax relief coming from Uncle Sam would not cover it.  If you study your electric section in the maint manuel for the 4106 you will see that this particular relay is highly complex and has three distinct functions.  It prevents the starter from operating while the generator is working, it prevents the blower motors from coming on until the generator is producing a set current, and it controls the operation of the "not gen" light on the dash.  If, as in most conversions, your blower motors have been removed, you no longer need the most complex function the relay provides.

hth

tg

Offline Stan

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Re: Pulsating lights
« Reply #8 on: April 22, 2008, 11:42:12 AM »
I believe all 4104 buses (except for the very last ones made) came from the factory with a generator. the 4106 model had an alternator right through the production run.

Always keep in mind that when you buy something used (even a one year old bus) it may not be the way it was originally built. Another interesting fact is that bus companies put different options on for different customers. Greyhound, in particular got bus models and options that were not available to anyone else. These two facts have caused many discussions and dog fights on the bulletin boards when both parties were correct in their observations.

Offline tekebird

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Re: Pulsating lights
« Reply #9 on: April 22, 2008, 08:12:56 PM »
man I thought I had several, unfortunately the part number of the ones I  have is 1118522

Offline DrivingMissLazy

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Re: Pulsating lights
« Reply #10 on: April 23, 2008, 07:05:34 AM »
As I recall, the invention of the high current silicon diode in the late 50's opened the way to convert AC to DC and one of the results was the invention of the alternator for use in vehicles. Prior to that time selenium rectifiers were used for this process. That is why you will find selenium rectifiers in the control circuitry of the 4104.

When converting a 4104 from positive ground to negative ground these selenium rectifiers must be replaced as they are the wrong polarity after the conversion of positive ground to negative ground.

Richard
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride

 

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