Onan Gurus...a question

[BracketNova]

Picked up a different trailer last weekend. Long story short my 12500 Quiet diesel won't start. The tank was bone dry when I got it, I added fuel - still nothing. I pulled the fuel line after the filter and it pumps fuel. I pulled the air filter and cranked it some more and still nothing. It just cranks and cranks. I read in the book that after the fuel is ran dry, you may need to prime it for one minute. I tried that and still no ignition. The only time I get a code is when the battery gets weak, it will then flash a 45. But, with the charger on it it has no codes, just cranks.


Ideas?

[chpcamaro]

ok are we talking generator or truck lol diesels need to be primed to start when they go dry

[ytnova]

Is is huffing any smoke when you crank it? No smoke=no fuel. If it is huffing white smoke, it has fuel, but either not enough engine speed(low battery) or glow plug issues. If no smoke, you are going to need to bleed the fuel system, fuel pressure is what opens the injector and if there is any air in the system, air compresses and will not open the injector. First bleed all the air from the fuel filter, usually they are gravity feed or have a small pusher pump and it will either have a bleed screw on the filter housing or loosen the line from the filter to the injection pump, get fuel there first, then tighten. Next, crack each line loose at each injector, crank until they squirt fuel. You can retighten any line that squirts a good volume of fuel. Once you get them all to squirt and you tighten them, it should start. If you get no fuel at all of the injectors, but you have fuel to the injection pump, start looking for some sort of cutoff switch on the injection pump, it should be hot(12volts) anytime the key is on. Let me know if this helps or you need more info.

[BracketNova]

Yes the Generator...

Good idea on cracking the injector lines. I pulled the feed line off the injector lines and it pumped fuel out, but I never thought to crack the lines at the injectors. However, it does huff white smoke when I crank it though. I was going to see if I could probe the glow plugs for twelve volts tonight. If I have twelve volts, my plan is to pull the glow plugs and power them up and see if they get hot. After that I would think it to be low compression - but it better not, it is supposed to have just had a $1500 service done.

[BracketNova]

Glow plugs aren't getting 12 volts. Not when priming, not for the 3-4 seconds before the starter engages, and not when cranking. Time to look for the relay I guess :)

[BracketNova]

Awesome....wire from the glow plugs goes to....the ECM. Not that I'm saying it is the ECM yet, but it is not looking good.


Looking into it more, and according to a cummins manual I found online, the temp sensor should read 700 ohms at room temp. It is currently open, so I'm hoping thats confusing the controller and it's not energizing the glow plugs. Time will tell.

[ytnova]

Sounds like you are on the right track, keep us posted.

[BracketNova]

Got the new coolant sensor in. Though it read the correct resistance, no dice.

[BracketNova]

Went ahead and cracked the nut on the top of an injector like YT mentioned...no fuel. There is fuel sitting in there - but it doesnt get sprayed/forced out. So, I am not sure why it used to (it has not been doing this today) puffs white smoke when I crank it. Then again, it will only do that if I'm giving it a boost from the charger. The batteries are new, but on the small side, only 600 ca.



I believe this is the stop solenoid above the arrow? The engine is a model 3LD1 Isuzu. It clicks when I put 12 volts to it. It doesn't when I let the controller handle it.

[BracketNova]

Took the injector lines off, amongst other things today, the injector pumps look to be blowing bubles when it is cranking...so there must still be air in them. After putting on a new fuel filter it passes the flow test. If anyone has ideas how to bleed these things I'm game. I'm suprised I haven't hurt the starter at this point.

[HPDRIFTER]

I mentioned this to my son, who is a Cummings tech. He said that if the starter switch is a rocker type, normally in the middle position, try pressing and holding it in the opposite direction from "start". If you hear a "clicking" sound, it should be the primer working.

[BracketNova]

Thanks Drifter...the primer does indeed work.

I also found out it is a model HDCAB Apec A not an HDKCB.

Anyhow - The cause for the lack of fuel was the stop solenoid not energizing. If I hotwire the solenoid and the glow plugs I can start it. Both of these items seem to be energized from the control module (~$604 yay!). With it started I get code 12 which is output voltage too high. If I recall it too is taken care of from the controller. I'm seeing a pattern here.

[BracketNova]

Looks like I got it gents....mostly


I eventually got down to pulling the controller to look for obvious signs of damage. I then figured I should check the oil pressure sender just for due dillagence. Well, when I hooked the controller back up - the stop solenoid started working. I started it up using jumped glow plugs...it started but still no output(voltage regulated in the same controller). Pulled the controller out again, checked the windings and plugged the controller in. This time after about 30 -45 seconds I heard a click (transfer switch?) and I had 119 volts. So I'm thinking maybe the contacts to the controller have some corrosion??? They don't look it, but the more I plug and unplug things the more things start working. At this point it looks like I will have to wire a relay to the glow plugs unless I want to shell out the money for the controller.

All in all it took me 20 hours to go through this thing