Onan 10k diesel Cranks but will not start ...Help

[YC1]

Can you get access to the glow plugs? You can measure their resistance.

[Mr_D]

Originally Posted by oldguy70

If you want to use a type of fluid to start you gen make sure you disconnect your glow
plugs or you will an explosion

Why? Starting fluid has been used for many, many years in diesels with glow plugs.
You CAN'T use it in the newer diesels with a heating grid in the intake like my 3126 and ISC had.
According to the Cummins spec sheet the QD 10000 and 12500 have automatic glow plugs. I have the 12500 in my rig and haven't had any problems starting it and it has automatic glow plugs.
Glow plug part number is 185-5990

[RobRoy]

Originally Posted by twinboat

Agree, but it may not be enough to fire. There should be dark gray to black smoke, if its trying to run.

If mine, I would pull the air filter out and mist the intake with WD40.

Day 2

Chapter 3.

I just pulled the air intake hose off the back of the air filter housing that runs directly to the intake.

First I check it for vacuum while cranking with my hand and have lots of vacuum.

Then while cranking I sprayed a liberal amount of WD-40 in the intake hose and no change still cranks with NO start and puffs of smoke out the exhaust.

I'm stumped because of how I thought diesel's operated I thought that this thing had to do something with the intake track is open and lots of vacuum and Sprayed fuel WD-40 in the intake hose and it sounds like it has tons of compression cranking ...nothing! .... cranks and no firing sound at all.........What am I missing?

Im thinking Im missing something very simple and going to feel like an idiot when I find out the issue.

[twinboat]

Originally Posted by Mr_D

Why? Starting fluid has been used for many, many years in diesels with glow plugs.
You CAN'T use it in the newer diesels with a heating grid in the intake like my 3126 and ISC had.
According to the Cummins spec sheet the QD 10000 and 12500 have automatic glow plugs. I have the 12500 in my rig and haven't had any problems starting it and it has automatic glow plugs.
Glow plug part number is 185-5990

We used all the time, but I didn't own the engines, I sprayed it in. I wouldn't use it on my own.

There only one, I recall, that blew the top of the piston into the oil pan. I didn't spray it but I had to fix it. Big Allas Chalmers demo dozer.

Starting fluid will clean the lubrication off the cylinder walls. Not a big problem with a cold enging getting some fuel but not so good with a no fuel situation.

Used in exess, it can explode in the cylinder, cracking the piston ring lands. Then the engine starts to have blowby.

A touch to much would lock up the older Cat engines. Cat had a starting fluid kit with a metered spray nozzle in the intake. Something like the pain button in hospitals. You can keep pushing it but you won't get more stuff.

WD40 at least is an oil, that also burns.

[flamebuster]

Sounds like you are on the right track. Yes the white smoke is unburnt fuel. The engine hasn't built enough heat yet from the compression cycle to burn the fuel completely. (That is why they use glow plugs.) due to the low compression ratio design of the engine.
Starting fluid will work as long as the glow plugs are not heating.. The hot glow plugs (if working) can pre ignite the fuel causing major damage. Your heating thru the air intake is a good idea but most likely, still not high enough heat.. Glow plugs are a very important part of the starting operation on these engines in my opinion.

[Road Hawg]

Originally Posted by RobRoy

Day 2.



Chapter 2.



Pulled the panel above the start switch on the genny itself to check the fuses and both fuses looked good and checked good with and ohm meter and they both have power at both side of the fuses.



So then I have a brain storm.



Because of seeing the smoke from the exhaust while cranking and no start I decided to remove the air filter and put my heat gun up inside the intake hose and give it a try thinking it has something to do with glow plugs and preheat ....................Nothing! still cranks over but no start, not even a bit of anything indicating it's trying to fire up..other than white puffs of smoke.

RobRoy

Not sure about the 10k but the 7500 has 3 fuses under the control panel. The third one is a little harder to locate but it's there.
And, it's a 25 amp fuse so it might be the one you're looking for.

[Road Hawg]

RobRoy
Again, not sure if your 10k is the same as the 7500, but I wanted to let you know I found my Onan manual and it shows 3 fuses under the control panel.
One 10 amp marked Control Circuit
One 10 amp marked Starter Solenoid
One 25 amp marked Glow Plug Circuit
Hope this helps.

[RobRoy]

Originally Posted by Road Hawg

RobRoy
Again, not sure if your 10k is the same as the 7500, but I wanted to let you know I found my Onan manual and it shows 3 fuses under the control panel.
One 10 amp marked Control Circuit
One 10 amp marked Starter Solenoid
One 25 amp marked Glow Plug Circuit
Hope this helps.

Thank you for your input.

I just checked my service information manual on my 10k and it shows and refers to only two fuses under that panel.

When I search the complete service manual it does not show nor refer to any glow plug fuse. Not saying no ...just saying I cant find anything that refers to such.

[Twomed]

Originally Posted by Road Hawg

RobRoy
Again, not sure if your 10k is the same as the 7500, but I wanted to let you know I found my Onan manual and it shows 3 fuses under the control panel.
One 10 amp marked Control Circuit
One 10 amp marked Starter Solenoid
One 25 amp marked Glow Plug Circuit
Hope this helps.

10k is the same... with the top cover removed you can almost see them. Up high front corner opposite coolant tank.


Just read back and see you found fuses... also 3 relays in there. Common relay... might try those.

[RobRoy]

Day2

Chapter 4

Still the genny cranks but no start.

So, I just talked to a friend who does HD diesel and has done some work on Onan generators.

I had mentioned to him that I'm stunned that it won't try to start when adding WD-40 and heating the intake air with a heat gun....and I found that pretty confusing.

He did some checking called me back and that he was pretty sure if the governor actuator failed that the genny would not run no matter what I did.

So I ohm checked the governor actuator and spec is 2.8-2.9 ohms It checked at 3.0 so I'm calling the windings good. However, he thinks that the pintle may be sticking or whatever?.

So I decided to try and remove the governor actuator and found out it requires a 2-inch open end wrench, so as Murphy's law works I have a 1 3/4 and now need to find a 2-inch open end.

Wow is this thing kicking my butt?

[RobRoy]

Originally Posted by Twomed

10k is the same... with the top cover removed you can almost see them. Up high front corner opposite coolant tank.


Just read back and see you found fuses... also 3 relays in there. Common relay... might try those.

The two fuses I found are mounted under the access panel where he radiator cap is located.

Youre saying look on the opposite side for a 3rd fuse?

I keep thinking that even if it is a glow plug issue that being that it's almost 40f degrees ambient air it would still try to start


Thanks for your input

[Twomed]

Glad you are on... check PM I just sent you a long reply.

[igave]

This probably isn't the issue; but ours (8000 q) will not start if it thinks the main fuel tank is 1/8 or so low. Acts like it should, but won't.If your sensors are off a little, or tilted opposite the sensor it may figure you need more fuel. Simple, but it could just be a misread on your tank.

[RobRoy]

Originally Posted by Twomed

Glad you are on... check PM I just sent you a long reply.

Thank You.