Very bizarre generator problem

[John C]

For whatever reason , I couldn't start the generator(I was able to start a few weeks ago), no even with the switch on the generator, the switch light is on (I don't remember it was on before), when I pushed it, I heard the "click" sound, I checked the battery connection to the generator when I am unplugged , it was12.7V

When I open the engine cover, there was A LOT of DUST inside the engine bay ,I used a strong blower to blow all the dust, after that I used a wet towel wipe everywhere I can reach.
After that I tried again, still didn't work, The are two wires connector outside of the engine (see attached), so I used multi-meter to test the voltage to find out what is the voltage going to the engine. At the same time asked DW to push the start, the voltage measurement went from 10mv to 9v-11v->higher (Voltage varies maybe because the multi-meter didn't touch the connectors very well, for a few seconds I heard the crank sound, then the Engine STARTED!!!

https://photos.app.goo.gl/LRLGc6B1KYKdnbLMA

 

I just couldn't believe it, I let it run for 15 minutes, stopped and then pushed start again, it still worked!

Unfortunately the next day, it won't start again, but when I used the multi-meter, it worked again!

Because there are so many nuts I have to remove in order to open the engine compartment, I just couldn't do this all the time.

What else should I try?

Please advise.

Thank you.

 

 

 

 

 

 

 

Edited March 14 by John C

[Just Jim]

A little more info would be good.  When you press the start button, you hear the fuel pump come on?  Every time or just sporadically?  Is the outside temp changing significantly from when it starts to when it will not?  Colder temps will require longer pre heat times.   You obviously have plenty of fuel in the tank as it will not run when the fuel level is low.  It cranks every time but does not start?  The oil and coolant levels are where they should be? Lets get some of the basic, easy things eliminated first. Please be a little more specific with what is happening.

[FishAR]

My 10 kw won't turn over half the time. Batteries fully charged. It's so far from the batteries to the generator I blame it on this and maybe the wire is undersized, not sure.

I hit the battery boost and it will start.

[MyronTruex]

Watching the video of pushing the switch I see nothing wrong. Depending on the temperature the glow plugs have to warm up. There is a chart for the approx time.

When it is cold or cool I often cycle the switch for a few seconds, then do this a couple of times before just holding it down. It can seem like it takes forever to turn over and start.

I did find one or two glow plugs bad a long time ago. There is a fuse behind the radiator filler. You have to do some tugging to get to it. 

I suspect your taking it apart was enough time for things to warm up and just a coincidence using the voltmeter. 

This is assuming the flashing light and fuel pump noise was always happening.

If not, there is a harness along the outside on the left as you face the generator that has given problems. Often it just needs to be exercised by pulling it apart and putting it back together a few times. Dielectric grease is fine or a light shot of WD40.

When I replaced my bad glow plug I replaced all three because it is a real pain to get to them as you noted. Sure glad we have the slide out. 

pre-heat times Onan Generator.pdf

[Tom Cherry]

3 hours ago, FishAR said:

My 10 kw won't turn over half the time. Batteries fully charged. It's so far from the batteries to the generator I blame it on this and maybe the wire is undersized, not sure.

I hit the battery boost and it will start.

There is a very lengthy and informative topic on this.  You have the “Monaco” ghost.  The Camelot circuits are totally different from the Dynasty….so, don’t try to connect dots that are like Mars and Venice.

You need to do some troubleshooting and research.  I KNOW this is a problem on the 2008 & up, but I THINK you have a different FRB and maybe RRB.  So, here are the basics.

First…ODDS ARE…you have a GROUND issue….that is assuming you have good House Batteries.  Mine did the same thing, even on the smaller 8.0 KW.

Go behind the battery box.  There are TWO Grounds there.  One if for HOUSE and other is Chassis.  Loosen or pull the cables off and clean the frame and the terminals.  Put it back together.  I think that is the issue. You have a bad or corroded HOUSE ground.  Looks OK, but needs PM and cleaning.

The reason….when you have great HOUSE batteries….and the genny no start…the run to the front and the need for a solid ground is super important.  I was able to troubleshoot mine with a VOM.  When the House bank tray was in, there was a tiny bit of resistance from the negative to a clean, good chassis ground.  Chassis batteries were ok….upon or closed or any point in between.  GREAT. I finally pushed in the House Bank slowly and the flexing of the ground cable did not result is a high resistance connection.  Worked for the rest of our 7K mile trip.  Fixed it at home.

NOW, my confidence in that being yours….again, assuming the House bank is OK….when younuse the BOOST, then the chassis batteries are “in” the circuit and you have a good ground and a good bank.

Clean the grounds.  If no joy post, and I’ll pull your prints….and look at the “cabling”.

 

[Tom Cherry]

10 hours ago, John C said:

For whatever reason , I couldn't start the generator(I was able to start a few weeks ago), no even with the switch on the generator, the switch light is on (I don't remember it was on before), when I pushed it, I heard the "click" sound, I checked the battery connection to the generator when I am unplugged , it was12.7V

When I open the engine cover, there was A LOT of DUST inside the engine bay ,I used a strong blower to blow all the dust, after that I used a wet towel wipe everywhere I can reach.
After that I tried again, still didn't work, The are two wires connector outside of the engine (see attached), so I used multi-meter to test the voltage to find out what is the voltage going to the engine. At the same time asked DW to push the start, the voltage measurement went from 10mv to 9v-11v->higher (Voltage varies maybe because the multi-meter didn't touch the connectors very well, for a few seconds I heard the crank sound, then the Engine STARTED!!!

https://photos.app.goo.gl/LRLGc6B1KYKdnbLMA

 

I just couldn't believe it, I let it run for 15 minutes, stopped and then pushed start again, it still worked!

Unfortunately the next day, it won't start again, but when I used the multi-meter, it worked again!

Because there are so many nuts I have to remove in order to open the engine compartment, I just couldn't do this all the time.

What else should I try?

Please advise.

Thank you.

 

 

 

 

 

 

 

John, time to start troubleshooting from the source and not do major surgery as likely there is NOT a problem in the Genny.

Read my RESPONSE to FishAR.  Clean the Ground Studs on both banks….if you have 2 house banks, then odds are 3 ground studs.

Next….follow the Positive and Negative from the Genny.  BE CAREFUL when you do the following.  Loosen the battery studs on the Genny cable connections.  Clean and then clean the terminals.  Next….retighten carefully.  A Ground Stud is a STEEL bolt welded onto the frame.  The bolts on the Genny is a copper or brass stud.  Tighten snugly….then a touch more.  You can’t just “rare down on it”….it will snap….and one very experienced member found out.

NOW…check the other ends of the genny cables.  Do the same bit for the negative, wherever it is connected to the frame….and then check the positive connection.

NOW…..a word on the #2 cables going to the Genny.  They are GROSSLY undersized.  Many people can’t crank or have issues…..MONACO GOOFED.  There is a lengthy topic on this and the fix….it AIN’T NO ADDITIONAL UP FRONT BATTERY FOR THE GENNY.

The next step is to replace the cables with a 2/0 (00) set of cables.  Most welding shops or welding suppliers can make you up a nee set of cables.  WAY EASIER than fabricating brackets and then cobbling up wiring and then figuring out how to actually CHARGE the standalone battery…

REREAD your post.  The CLICK is the giveaway.  The starter solenoid engaged.

THEN NEXT TIME or tomorrow….after you clean your cable ends and grounds….if it doesn’t work…..try the BOOST Switch.  It will bring in the House as well and might jusT supply enough power….

Then report back….KISS and do the simple fixes or trouble shooting and not get into the more complex…..

 

[waterskier_1]

I didn't see where you connected the positive probe in the pictures.  It would be interesting to purees on the same place with a small screwdriver.  I'm wondering is where you are applying pressure is has a bad or dirty connection, and the pressure is making better contact? 

- Rick N 

Tucson,  AZ 

[grizzly]

When I had a starting problem in the past what I did was go into the back engine bay and take my Big Boy off and clean it and never had an issue since then. That's what worked for my case

[Tom Cherry]

That means your cables up front are the issue.  If you needed the Big Boy or the “boost”, you have a voltage reduction…most likely the undersized #2 cables that should have been 2/00 (00) cables.

Also remember, the Big Boy drops out when the rig is NOT PLUGGED IN or the ENGINE IS NOT RUNNING.  Don’t know the conditions, but the only scenario where cleaning the contacts on a Big Boy would make a difference is when one side or the other would be charging.  In your case, starting the engine would pump at least 150 Amps (charging) into the Chassis….which is where your Genny also starts.

FIX, actually replace the undersized cables…..or start the Engine or try the Boost (assuming the Big Boy contacts are clean and working).

Hope this explains what is actually happening….you could have a “supplemental” battery….as some do, that is ONE HALF the capacity of ONE of your Chassis batteries….and if if we’re properly cabled, it would start the Genny on a frosty morning….

When folks add the UNNECESSARY supplemental battery…first thing they do is replace the PUNY cables….had they reviewed the circuit and the ampacity of the #2 cables….no need for a separate battery….

MONACO GOOFED.  Some never have an issue…..in fact, probably 90% don’t…but the fix is to cable properly….

1 hour ago, waterskier_1 said:

I didn't see where you connected the positive probe in the pictures.  It would be interesting to purees on the same place with a small screwdriver.  I'm wondering is where you are applying pressure is has a bad or dirty connection, and the pressure is making better contact? 

- Rick N 

Tucson,  AZ 

100 % agree.  Frank has stated that the chassis harnesses are a real issue..  They are NOT that robust or waterproof.  We are finding more and more corrosion isdues…age is taking its toll.  The Genny communication or control voltage harness…particularly near the genny has always been a weak point….

[John C]

8 hours ago, MyronTruex said:

Watching the video of pushing the switch I see nothing wrong. Depending on the temperature the glow plugs have to warm up. There is a chart for the approx time.

When it is cold or cool I often cycle the switch for a few seconds, then do this a couple of times before just holding it down. It can seem like it takes forever to turn over and start.

I did find one or two glow plugs bad a long time ago. There is a fuse behind the radiator filler. You have to do some tugging to get to it. 

I suspect your taking it apart was enough time for things to warm up and just a coincidence using the voltmeter. 

This is assuming the flashing light and fuel pump noise was always happening.

If not, there is a harness along the outside on the left as you face the generator that has given problems. Often it just needs to be exercised by pulling it apart and putting it back together a few times. Dielectric grease is fine or a light shot of WD40.

When I replaced my bad glow plug I replaced all three because it is a real pain to get to them as you noted. Sure glad we have the slide out. 

 

pre-heat times Onan Generator.pdf 474.68 kB · 4 downloads

No sure if it was because of the temperature, Here in So California, it is about 67 degrees when I was doing it...

[John C]

6 hours ago, Tom Cherry said:

John, time to start troubleshooting from the source and not do major surgery as likely there is NOT a problem in the Genny.

Read my RESPONSE to FishAR.  Clean the Ground Studs on both banks….if you have 2 house banks, then odds are 3 ground studs.

Next….follow the Positive and Negative from the Genny.  BE CAREFUL when you do the following.  Loosen the battery studs on the Genny cable connections.  Clean and then clean the terminals.  Next….retighten carefully.  A Ground Stud is a STEEL bolt welded onto the frame.  The bolts on the Genny is a copper or brass stud.  Tighten snugly….then a touch more.  You can’t just “rare down on it”….it will snap….and one very experienced member found out.

NOW…check the other ends of the genny cables.  Do the same bit for the negative, wherever it is connected to the frame….and then check the positive connection.

NOW…..a word on the #2 cables going to the Genny.  They are GROSSLY undersized.  Many people can’t crank or have issues…..MONACO GOOFED.  There is a lengthy topic on this and the fix….it AIN’T NO ADDITIONAL UP FRONT BATTERY FOR THE GENNY.

The next step is to replace the cables with a 2/0 (00) set of cables.  Most welding shops or welding suppliers can make you up a nee set of cables.  WAY EASIER than fabricating brackets and then cobbling up wiring and then figuring out how to actually CHARGE the standalone battery…

REREAD your post.  The CLICK is the giveaway.  The starter solenoid engaged.

THEN NEXT TIME or tomorrow….after you clean your cable ends and grounds….if it doesn’t work…..try the BOOST Switch.  It will bring in the House as well and might jusT supply enough power….

Then report back….KISS and do the simple fixes or trouble shooting and not get into the more complex…..

 

Tom @Tom Cherry,

I removed the nuts of two ground, cleaned the cables with "WD-40 SPECIALIST 11 oz. Contact Cleaner, Quick-Drying Electric Equipment Cleaner " , put everything back, try it again, still didn't work. But this time at least the light on the switch button went away. that is a improvement.

I start the coach engine, push the "boost" switch, still the same.

I kept trying and until I heard a crank sound, then it went away quickly, the next time I kept holding the switch, then all of sudden, the generator started!

Thank you so much.

I guess it is because of the grounds and the time I need to hold the generator.

One more question, my generator switch in the bedroom light is always on and I couldn't start the generator with this switch, nor can I start from the driver dash board., Does that means there is a communication problem between the remote switch and the generator? how do I fix that, I already cleaned the connect between the coach wire and the generator with "Drying Electric Equipment Cleaner "

Thanks again.

One more question, I still can not

4 hours ago, waterskier_1 said:

I didn't see where you connected the positive probe in the pictures.  It would be interesting to purees on the same place with a small screwdriver.  I'm wondering is where you are applying pressure is has a bad or dirty connection, and the pressure is making better contact? 

- Rick N 

Tucson,  AZ 

I already took the nuts out and clean the cable heads with "WD40 Drying Electric Equipment Cleaner", I did that with all the connection I can see...

[Tom Cherry]

11 minutes ago, John C said:

Tom @Tom Cherry,

I removed the nuts of two ground, cleaned the cables with "WD-40 SPECIALIST 11 oz. Contact Cleaner, Quick-Drying Electric Equipment Cleaner " , put everything back, try it again, still didn't work. But this time at least the light on the switch button went away. that is a improvement.

I start the coach engine, push the "boost" switch, still the same.

I kept trying and until I heard a crank sound, then it went away quickly, the next time I kept holding the switch, then all of sudden, the generator started!

Thank you so much.

I guess it is because of the grounds and the time I need to hold the generator.

One more question, my generator switch in the bedroom light is always on and I couldn't start the generator with this switch, nor can I start from the driver dash board., Does that means there is a communication problem between the remote switch and the generator? how do I fix that, I already cleaned the connect between the coach wire and the generator with "Drying Electric Equipment Cleaner "

Thanks again.

One more question, I still can not

I already took the nuts out and clean the cable heads with "WD40 Drying Electric Equipment Cleaner", I did that with all the connection I can see...

OPPS...  Again...an ASSUMPTION.  The Genny Start system is integrated into the MPX system.  WHOLE NEW BALL GAME as to Controls.  THAT also explains WHY your VOM, I THINK, caused the "Bizarre" situation....that is assuming that ALL the Gen Start Switches are on the LIGHTED MPX Panel.

IN THE FUTURE...  PLEASE state where any funky SWITCH is located.  IT DOES MAKE A DIFFERENCE...MOST folks are NOT attuned to such...as we have "PLAIN JANE SWITCHES"

OK....NOW to your issues.

I STILL SUPSECT VOLTAGE ISSUES....so that needs to be addressed FIRST.  The best way to tell...  RUN A JUMPER CABLE.

SO...here is what you do.  Move your Vehicle near the GENNY so you can get jumper cables underneath or on the BACK two studs of the Genny.

NOW....do this exactly as written. 

TURN OFF THE BATTERY CUT OFF SWITCH at the DOOR

TURN OFF the DISCONNECT SWITCHES....both HOUSE and CHASSIS. 

Then Hook up the POSITIVE and the NEGATIVE (Jumper Cables) to the Genny battery cable terminals.  YES...they are a bit small...but will work.

NOW...  THEN scoot out and HOOK up the jumper cables...(MINDFUL of the POLARITY) to your car or whatever vehicle.

THEN...  TURN ON BOTH House Disconnect switches.  Wait a minute or so.  

THEN...  Turn on the Battery Cutoff switch.  That will reboot your CPU and the Intellitec MPX.

NOW...  wait about 5 minutes.  Test a light or a fan or the water pump or any switches on any of the LIGHTED Key pads...

DID THAT RESOLVE THE GENNY SWITCH in the Bedroom.  IF NOT...then that is a DIFFERENT ISSUE...I think...

NOW...  Go to the FRONT of the Generator or move the Genny Slide out.  IT COULD have been out before...which ever is easier.  Push the START SWITCH on the PANEL or the UP FRONT CONTROL box.  IT should START instantly.

That means that you have GOOD POWER to the Genny (from the vehicle) to Start.

Let it run for about 5 minutes and THEN shut it off from the inside....say the dash or wherever the front (near the cockpit) lighted switch panel is. THAT SHOULD WORK...  BUT REPORT WHAT DOES and WHAT DOES NOT WORK.

OK....wait about 5 minutes for the Genny to cool off.  NOW try the Genny Switch up front.  I THINK it will start FINE.  IF SO....then we have isolated the issue as a HIGH RESISTANCE connection or STUPID UNDERSIZED cables.

You STILL need to clean the Battery Stud Grounds at the back.  You STILL need to clean the ground cable up front to whereever it is GROUNDED....as well as where the Positive it.  If that don't fix it.  GET NEW CABLES....

NOW... Here is where I hand you off.  @Frank McElroy needs to chime in here if you have lights or issues with the MPX switches.  I THINK that when you use the VOM....it actually "sent a signal" to start... BUT, I am at a LOSS at to WHERE you have the VOM.  Maybe Frank can noodle it out. What I told you to do is how you TROUBLE SHOOT Voltage issues....

The Genny SHOULD start with good voltage from the vehicle and using the UP FRONT Switch is NOT part of the MPX system...

 

[Paul J A]

You may want to consider a; https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

Install a battery in the genny compartment, a  "certain" Motorcycle battery has enough CCA's.,  and get the power for charging from the FRB. Abandon those undersized cables, 40' long from the rear to front.

[Just Jim]

I occasionally have trouble starting the genset.  It has acted like the batteries were weak when I knew they were not... now I know why.  I love this group!!!  However, now I have another project to work on.  LOL.  IF, you had a battery for just the genset, will all the switches inside still work to start it?  It seems it would be more complicated than just wiring in a battery???

[det944]

Any possibility this could be the chassis battery switch on the battery compartment? Just a thought.My Dynasty has the phantom gen start issue but using the boost switch gets it going. I've cleaned all connections mentioned in these posts.

[Tom Cherry]

32 minutes ago, Just Jim said:

I occasionally have trouble starting the genset.  It has acted like the batteries were weak when I knew they were not... now I know why.  I love this group!!!  However, now I have another project to work on.  LOL.  IF, you had a battery for just the genset, will all the switches inside still work to start it?  It seems it would be more complicated than just wiring in a battery???

The interior switches have no connection to “lack of voltage”.  Ok…in your case, if you are having to use the BOOST….ODDS ARE (memory) you have the same Monaco Goof.  I think i have chased this back a few years….but CHECK it out.  If you have # 2 cables to the genny….that is the issue.  When you are using the BOOST, you are only applying a bandaid.

You would replace the cables if you added a battery…LOL.  Then fab up a bracket, make cables, buy a battery….and cobble up a way to charge it.  Most folks report issues figuring out how to charge….without blowing up the alternator.  Two big Chassis batteries and then add in another…even with your 200 Amp battery, you are pushing it.

Focus on the issues…verify the cable sizes.  Why spend several hundred $$ and then worry about premature failure of the alternator or some crazy way to charge the aux battery from the house???

 

59 minutes ago, Paul J A said:

You may want to consider a; https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

Install a battery in the genny compartment, a  "certain" Motorcycle battery has enough CCA's.,  and get the power for charging from the FRB. Abandon those undersized cables, 40' long from the rear to front.

Look at the prints.  Most of the Dynasty’s at least 2005 or so up, have puny #2 cables that connect the genny to the FRB.  There is usually a 4/0 (0000) cable running to the FRB.  If one has a #2 cable from the rear, the genny would NEVER START….Pure physics and reading the Ampacity charts.

The problem is the undesized cables from the FRB posts.  That is why adding a battery without understanding the problem is a mistake.  You could even probably run the test with 2 pairs of lightweight jumpers.

That “motorcycle” battery, chosen because of size has, IIRC correctly, half or less than the SINGLE 950 (900?) CCA chassis battery….

Problem aint the run uo front….the shorter, much shorter run from the FRB to the Genny….

Hope this explains it better….

[Frank McElroy]

2 hours ago, John C said:

Tom @Tom Cherry,

I removed the nuts of two ground, cleaned the cables with "WD-40 SPECIALIST 11 oz. Contact Cleaner, Quick-Drying Electric Equipment Cleaner " , put everything back, try it again, still didn't work. But this time at least the light on the switch button went away. that is a improvement.

I start the coach engine, push the "boost" switch, still the same.

I kept trying and until I heard a crank sound, then it went away quickly, the next time I kept holding the switch, then all of sudden, the generator started!

Thank you so much.

I guess it is because of the grounds and the time I need to hold the generator.

One more question, my generator switch in the bedroom light is always on and I couldn't start the generator with this switch, nor can I start from the driver dash board., Does that means there is a communication problem between the remote switch and the generator? how do I fix that, I already cleaned the connect between the coach wire and the generator with "Drying Electric Equipment Cleaner "

Thanks again.

One more question, I still can not

I already took the nuts out and clean the cable heads with "WD40 Drying Electric Equipment Cleaner", I did that with all the connection I can see...

When a keypad indicator light turns ON after pressing it, it ONLY means that the keypad was pressed and the Intellitec CPU acknowledged that it was pressed by turning ON the indicator light.

It does NOT mean that, in this case, the generator ever started - it was ASSUMED to have started. 

Press the keypad again and the indicator light should go out.

[Tom Cherry]

1 hour ago, Frank McElroy said:

When a keypad indicator light turns ON after pressing it, it ONLY means that the keypad was pressed and the Intellitec CPU acknowledged that it was pressed by turning ON the indicator light.

It does NOT mean that, in this case, the generator ever started - it was ASSUMED to have started. 

Press the keypad again and the indicator light should go out.

NOW WHY did that not hit me.  The MPX has done it’s job….sent out the signal….and assumes the Generator cooperated.

Such a simple explanation…. LOL….thanks….

SO, John…run my tests….I think you have a voltage issue….

1 hour ago, Paul J A said:

You may want to consider a; https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

Install a battery in the genny compartment, a  "certain" Motorcycle battery has enough CCA's.,  and get the power for charging from the FRB. Abandon those undersized cables, 40' long from the rear to front.

Look at the prints.  Most of the Dynasty’s at least 2005 or so up, have puny #2 cables that connect the genny to the FRB.  There is usually a 4/0 (0000) cable running to the FRB.  If one has a #2 cable from the rear, the genny would NEVER START….Pure physics and reading the Ampacity charts.

The problem is the undesized cables from the FRB posts.  That is why adding a battery without understanding the problem is a mistake.  You could even probably run the test with 2 pairs of lightweight jumpers.

That “motorcycle” battery, chosen because of size has, IIRC correctly, half or less than the SINGLE 950 (900?) CCA chassis battery….

Problem aint the run uo front….the shorter, much shorter run from the FRB to the Genny….

Hope this explains it better….

[John C]

2 hours ago, Frank McElroy said:

When a keypad indicator light turns ON after pressing it, it ONLY means that the keypad was pressed and the Intellitec CPU acknowledged that it was pressed by turning ON the indicator light.

It does NOT mean that, in this case, the generator ever started - it was ASSUMED to have started. 

Press the keypad again and the indicator light should go out.

Hi,Frank @Frank McElroy,

My keypad(bedroom) indicator was on all the time when the generator was no on,( it was off before). no matter I press the keypad (I did hear the click sound) how many times, it is always on. I can't start the generator from the keypad right now.

Now after I started generator using the switch next to the generator, My keypad indicator light went off, but when I turned off the generator , the keypad indicator went back on again.

It is totally reverse the behavior it is suppose to be, it should be off when generator no on and should be on when generator is on.

The switch indicator (outside next to generator) light is on most of time(not normal) . After most than 11 second pressing on the switch , (I remember I was only need to press 5 second before ), the generator did start, and the switch indicator getting brighter than it was before I started the generator.

14 hours ago, MyronTruex said:

Watching the video of pushing the switch I see nothing wrong. Depending on the temperature the glow plugs have to warm up. There is a chart for the approx time.

When it is cold or cool I often cycle the switch for a few seconds, then do this a couple of times before just holding it down. It can seem like it takes forever to turn over and start.

I did find one or two glow plugs bad a long time ago. There is a fuse behind the radiator filler. You have to do some tugging to get to it. 

I suspect your taking it apart was enough time for things to warm up and just a coincidence using the voltmeter. 

This is assuming the flashing light and fuel pump noise was always happening.

If not, there is a harness along the outside on the left as you face the generator that has given problems. Often it just needs to be exercised by pulling it apart and putting it back together a few times. Dielectric grease is fine or a light shot of WD40.

When I replaced my bad glow plug I replaced all three because it is a real pain to get to them as you noted. Sure glad we have the slide out. 

 

pre-heat times Onan Generator.pdf 474.68 kB · 5 downloads

On the 2nd thought, I think to hold the switch on the generator helps a lot, it maybe the only factor. From unable to start the generator to able to startit, the key difference is I held the switch much much long . The problem is I don't remember I have to hold the start switch that long before, it must be half of the time I am holding right now, and the temperature is actually much warmer than it was one month ago (when I can star the generator by holding the switch half long), no sure why now I need hold the switch twice long?

Edited March 15 by John C

[John C]

1 hour ago, Tom Cherry said:

NOW WHY did that not hit me.  The MPX has done it’s job….sent out the signal….and assumes the Generator cooperated.

Such a simple explanation…. LOL….thanks….

SO, John…run my tests….I think you have a voltage issue….

Look at the prints.  Most of the Dynasty’s at least 2005 or so up, have puny #2 cables that connect the genny to the FRB.  There is usually a 4/0 (0000) cable running to the FRB.  If one has a #2 cable from the rear, the genny would NEVER START….Pure physics and reading the Ampacity charts.

The problem is the undesized cables from the FRB posts.  That is why adding a battery without understanding the problem is a mistake.  You could even probably run the test with 2 pairs of lightweight jumpers.

That “motorcycle” battery, chosen because of size has, IIRC correctly, half or less than the SINGLE 950 (900?) CCA chassis battery….

Problem aint the run uo front….the shorter, much shorter run from the FRB to the Genny….

Hope this explains it better….

@Tom Cherry I already run a voltage test from the cable nuts connector outside the generator, it was 13.6V when I connected to the shore power, when I am not connected shore power, it was 12.7V. when I pressed the switch outside the generator, the voltage connector to the engine was 0-10v->11.5v -> higher (when the switch is press, when switch not pressed, it was 0)

Note, when I say switch, I mean the switch out the generator box, not inside the coach.

The more I think about, this "bizarre behavior" is actually no bizarre AT ALL, I believe when I was using multi-meter, DW was pressing the switch much longer (because I want to get the accurate voltage and that takes time) than I was press it when I was not using multi-meter.

This has nothing to do with the multi-meter all all!!!!

Of course I still don't know why I need to press the switch button twice long than it was before.

and why I can't start the generator from my keypad (inside my bedroom) and my keypad's behavior is reverse what it should be.

 

[Frank McElroy]

9 hours ago, John C said:

Hi,Frank @Frank McElroy,

It is totally reverse the behavior it is suppose to be, it should be off when generator no on and should be on when generator is on.

With the generator off, reboot the Intellitec CPU by either cycling the battery cutoff switch or disconnect the batteries.  This should bring the keypad indicator light back in sync with the generator being ON/OFF.

[Frank McElroy]

If you are still having a sync problem, you'll need to trace wiring to be sure the Intellitec system is getting proper generator input signals.

38070198 (Schematic, Gen Start, Auto Temp).pdf

[Tom Cherry]

10 hours ago, John C said:

@Tom Cherry I already run a voltage test from the cable nuts connector outside the generator, it was 13.6V when I connected to the shore power, when I am not connected shore power, it was 12.7V. when I pressed the switch outside the generator, the voltage connector to the engine was 0-10v->11.5v -> higher (when the switch is press, when switch not pressed, it was 0)

Note, when I say switch, I mean the switch out the generator box, not inside the coach.

The more I think about, this "bizarre behavior" is actually no bizarre AT ALL, I believe when I was using multi-meter, DW was pressing the switch much longer (because I want to get the accurate voltage and that takes time) than I was press it when I was not using multi-meter.

This has nothing to do with the multi-meter all all!!!!

Of course I still don't know why I need to press the switch button twice long than it was before.

and why I can't start the generator from my keypad (inside my bedroom) and my keypad's behavior is reverse what it should be.

 

Back up.  What you need to understand is the relationship of the AMPS and VOLTAGE.  You “sort of” defined your problem…and it is, as I posted, a HIGH RESISTANCE issue.  Frank also instructed you, just as I did to reboot your Intellitec MPX.  I do NOT think you have a control issue, but you must understand and troubleshoot properly.

Just because you have higher…as in 13.6 VDC when on shore…..that does not mean that you have fully charged or good batteries.  That is the Magnum in FLOAT MODE.

Then, when you unplug from shore, you have 12.7 VDC. I think we have been down this path before and it is important that you learn and understand how Amps and Volts and Current Draw impacts each other or what to expect under load…..if not, then you will be chasing ghosts and really unhappy with your Motor Home.

OK…NOW…you have “good” or reasonable Voltage at the Chassis Bank.  However, your statememt about holding the switch too long is incorrect.  You have to understand WHERE to measure and what to expect.

JUST to confirm….when you say “connectors to the engine”….you actually mean the Generator Starting Studs….or where the 12 VDC is attached.  You said the voltage was 10 - 11.5 VDC…I HOPE that was when you pressed the switch….The Generator “studs” should measure at least 12 VDC and crank instantly.  So, you have low or inadequate voltage.

BUT….If I UNDERSTAND…..you have NO VOLTAGE on the studs when the Generator is just sitting idle. That is totally inconsistent….  First you said 13.6 on shore…then 12.7 when off shore…..then low…too low 10 - 11.5.. WHEN you start an engine, the amp draw will be from the “resistance” in the starter windings and YES…the voltage will drop.  BUT you have to read or measure the voltage at the starter connection….which is the two 12 VDC studs on the rear.  If you have inadequate…as in the batteries are not fully charged (12.7 can be a surface charge….we’ve discussed that before) and then if they are weak, the voltage will drop like a stone.

SO…if you want assistance, then please perform the tests as outlined and not do additional pne or become helter skelter.  It is impossible to reach a logical conclusion.

My request was very specific and would have isolated some issues.  Go back and read my post.  Hook up a pair of Jumper cables to the two studs (engine) and then use the front (on the generator’ switch.  We have to “remove” or eliminate the starter controls (inside and on the MPX).  Do that.  I suspect it will start quickly……..then report back.

THEN you can start following the correct troubleshooting for the voltage issues….not COMPLICATED….you, your wife and your VOM….but once we know that the Generator will start with an auxiliary battery….we can proceed and quit guessing or speculating…

Thanks,,,,

 

[John C]

3 hours ago, Frank McElroy said:

With the generator off, reboot the Intellitec CPU by either cycling the battery cutoff switch or disconnect the batteries.  This should bring the keypad indicator light back in sync with the generator being ON/OFF.

Yes, I did turn off the cutoff switches off and on for both chassis &  house batteries many times, that made no difference...

3 hours ago, Frank McElroy said:

If you are still having a sync problem, you'll need to trace wiring to be sure the Intellitec system is getting proper generator input signals.

38070198 (Schematic, Gen Start, Auto Temp).pdf 105.91 kB · 2 downloads

I looks like the connector between the  generator and coach Intellitec system is the problem, I did clean it really good,

I did see the diagram, but no sure how to test the 8 pins, where do I put the pos & nag of my multi-meter.

Thanks!

[Frank McElroy]

12 hours ago, John C said:

@Tom Cherry I already run a voltage test from the cable nuts connector outside the generator, it was 13.6V when I connected to the shore power, when I am not connected shore power, it was 12.7V. when I pressed the switch outside the generator, the voltage connector to the engine was 0-10v->11.5v -> higher (when the switch is press, when switch not pressed, it was 0)

If you are saying that with the voltmeter is connected to the battery cables on the back of the generator, the voltage goes to zero when you press the start switch on the generator, it means you either have dead coach batteries, or high resistance in one of 12 volt cables from the chassis battery bank or the ground cable connecting the generator to the chassis frame is bad.

First try connecting the voltmeter ground to the chassis frame, not the ground lug on the generator.  A loose generator ground cable would show the voltage readings you are seeing provided your voltmeter was actually on the +12 and ground connections on the generator.