Share |
DragRaceResults.Com    Bracket Talk    Bracket Talk Forum  Hop To Forum Categories  Tech Talk - by Abruzzi    onan 7.5 QD generator help
Go
New
Find
Notify
Tools
Reply
  
onan 7.5 QD generator help
 Login/Join
 
DRR Trophy
posted
I have a 7.5 onan generator model hdjak went out and started it up to let it charge house batteries, it started fine and ran heard a strange noise so I shut off and the starter was still cranking had to kill the batteries to get to quit.
now when I turn batteries on it starts cranking on its own, so I shut bat. off went to starter on gen disconnected the small soleniod wire turn batteries back on its fine no more cranking so I know problem is not solenoid or starter.
Looking for any ideas or some else that may of had this problem.

Thanks Scott


Photobucket 07 M & M PAR 582 SR20
Scott Skinner 330D
 
Posts: 125 | Location: South Orient, Illinois | Registered: November 24, 2006Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
sounds like starter drive might be stuck in(staying engaged with the flywheel, if you can see it and try and pry it out of engagement, install your wire and try again.
 
Posts: 42 | Location: Nova Scotia | Registered: February 06, 2012Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
posted Hide Post
I can not find an HDJAK

But there is an HDKAJ and it is a 7500 watt Diesel inverter.

I have one here now that I just did some work on....

I have not seen this problem myself...


I agree it could be a stuck starter and that was the noise you heard. With the small wire disconnected it kind of rules that out........but it
is worth checking into

I would check the rocker switch(s)....Disconnect the remote connector if it has one for a remote start switch.

If the rocker switches are ok and the remote wiring is not the problem I would make a guess that it has a starter relay.....a Bosch type relay that might be the problem...

After that it could be the ECU itself that is sending a signal to the relay to crank the engine.....The "brains" of the unit.....Potted PC board......
 
Posts: 1996 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
I have ruled starter out starter does not crank
with small wire that send 12v to solenoid disconnected it has constant 12v on it. I have also disconnect the remote start wiring it still has 12v on that wire.

SCDIV1 is there a separate relays like ice cube bosch under cowling that control that circuit


Photobucket 07 M & M PAR 582 SR20
Scott Skinner 330D
 
Posts: 125 | Location: South Orient, Illinois | Registered: November 24, 2006Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
posted Hide Post
I took a look in the Service and parts manuals for you.

This machine has no relays...I was thinking of a 10 or 12 fixed speed unit....they have 3 relays....

The controller is integrated with the inverter section.....and that is not good...

Basically if you have no wiring issue between the rocker switch and the plug that goes into the inverter section.....there is only one solution....replace the inverter/controller.

These units are known for doing odd things like this and there is no separate part to repair or replace. The inverter section is one sealed unit and not serviceable. Onan used to sell rebuilt units but they no longer do....new only.

Just to verify the rocker switch wiring down to the inverter would require the top cover to come off. I have never found anything wrong with a machine for something like that.

I cannot copy and paste the troubleshooting page for you that says "generator cranks on it's own without pushing the rocker switch".....but it lists only the switch and or it's wiring down to the control or the control itself....I can give you the pinouts and the connector positions......You can just trace the wires from the switch down and verify it is NOT showing any closure on the pair for starting.


I have had machines that were dead and did nothing, one that labored so bad during cranking it would not start and burnt up battery cables.......and other odd behaviors and it was the inverter section everytime.....

The part cost alone is around $1500 Cummins-Onan part number is 300-6058-02

Fits HDKAJ models with Spec Letter A thru K

Sorry for the bad news...


Another problem that I have seen is the magnets can come apart on the rotor and it makes a mess.....

You did say you heard a noise! That is generally not likely though and usually a catastrophic failure....

This message has been edited. Last edited by: SCDIV1,
 
Posts: 1996 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
SCDIV1 thanks for info don't sound good

I have had the gen running its for sure starter cranking, here's what I did with wire disconnected from starter had my boy hold the switch to start position I touch the solenoid wire to solenoid unit started right up and I pulled wire back off to keep it from cranking and I ran it for 2-3 hours ran fine.

Is the control board 1500 by itself and would have the part number?

Thanks for the help
Scott


Photobucket 07 M & M PAR 582 SR20
Scott Skinner 330D
 
Posts: 125 | Location: South Orient, Illinois | Registered: November 24, 2006Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
Sorry didn't see the part number Thanks


Photobucket 07 M & M PAR 582 SR20
Scott Skinner 330D
 
Posts: 125 | Location: South Orient, Illinois | Registered: November 24, 2006Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
posted Hide Post
It's not just a control board...

The inverter section is a sealed unit and the control is inside. The complete unit gets replaced and is NON serviceable. They have never offered any info on doing it any other way.

It is really not all that difficult a job to replace it....I have done quite a few...

I don't know why they stopped selling the rebuilt units.....they were about half the price....

I just installed a control board in a 10KW diesel. That is not an inverter and the board alone is over $600 from Cummmins....

As they say in some pats of the country....

Cummins is mighty proud of their parts....



I think the noise you heard was the starter re-engaging after the engine was running.....

This is a very common problem in the automatic generator world....We call it failure to crank disconnect.....and it destroys a lot of starters and flywheels....

My Duramax diesel in my pickup has a starter disconnect feature.....I am sure of it....Once the engine reaches a certain rpm the starter will not stay engaged even if I am holding the key down.....

My guess is there is a failure in your control relating to crank disconnect....
 
Posts: 1996 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Sportsman
posted Hide Post
If in runs and works fine, except for the starter staying engaged why not just put a push button switch in the small wire to the starter?


I used to be a people person, but people ruined that.
 
Posts: 586 | Location: Usually home | Registered: January 27, 2013Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
Thanks again SCDIV1 ill will look a little deeper later I just put it in storage

Woody I have thought same thing I guess if I need it before I get it fixed I will lay under it and touch the wire on solenoid

Scott


Photobucket 07 M & M PAR 582 SR20
Scott Skinner 330D
 
Posts: 125 | Location: South Orient, Illinois | Registered: November 24, 2006Reply With QuoteReport This Post



DRR Sportsman
posted Hide Post
FWIW, I just had a problem my MIG welder,it was mice making a new home & chewing on the insulation of the wiring.

It caused a short and after I repaired the damaged wires, it still has problems. It must have damaged the board since the gas solenoid is always energized regardless of the gun switch .

Just thought I would offer another scenario.

Good luck.

PS: Anyone have a good mouse repellant?


Cool
 
Posts: 173 | Location: Atco NJ | Registered: March 14, 2002Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
It could be that mice have chewed something up or other rodent

Luck hasn't been on my side so I'm sure it would have wiped board out also.


Photobucket 07 M & M PAR 582 SR20
Scott Skinner 330D
 
Posts: 125 | Location: South Orient, Illinois | Registered: November 24, 2006Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
posted Hide Post
I have not found mice to be the problem in machines like this. I don't think they like the diesel smell as I have never found them in any diesel powered machine.

Mice do a lot of damage for sure in piles of equipment I see...

I think the adding a cranking interruption switch idea is a good way to avoid spending a lot of money. If it works normally other than the cranking issue.....do it...
 
Posts: 1996 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
  Powered by Social Strata  
 

DragRaceResults.Com    Bracket Talk    Bracket Talk Forum  Hop To Forum Categories  Tech Talk - by Abruzzi    onan 7.5 QD generator help

© DragRaceResults.com 2014