Northern Lights Genset

[Msamsen]

I haven't read the whole thread so excuse me if previously mentioned. Did you check the fuel filters?

Yes. Both were changed. Fuel flows well up to the last bleed screw before the injector pump.

 

[Msamsen]

Can you get it to come to life on either?

It may be sucking air in still if you had a air problem to begin with.

Thanks for the input Towlou!
I cant get it to fire off even once. I have basically ruled out any air intrusion by installing a low pressure electrical priming pump in the system. That forces fuel through the lines and lift pump all the way to the injector pump. After that its just dribbles. Im going there today to see if I can pull off and clean the IP delivery valve and elements without removing the IP itself. Running out of options to try.

 

[Msamsen]

The Run Relay is the key for getting it started, and obviously the Starter Relay. If the fuel solenoid activates when you engage the override switch, then the Run Relay is working.

So was the lift pump recently changed? Was it changed as part of this effort? Has the gen run at all since replacing the lift pump?

I appreciate the feedback Twistedtree!
Yes the lift pump was changed as part of the effort to fix the no start, and no it hasnt started since. Seemed like a quick fix i could get delivered in two days through amazon. It was a perkins tractor part for the same engine but looked identical. Anyways, the pressure priming pump system I installed pushs fuel past the lift pump and to the 10 mm. bleed screw just prior to entering the IP. Thats the last real flow I get then its just dribbles at the injector lines.

 

[twistedtree]

I understand that you have tested the shutoff solenoid when removed from the injection pump, and see it moving. At the same time, everything you describe is consistent with a shutoff solenoid that is not operating correctly. So I think I'd go back over that again.


Some sort of internal injection pump failure that causes the generator to go from running fine to no-start seems very unlikely. On the other hand, the little cube solenoids do go bad over time, contacts get pitted, and current slow can be restricted. Perhaps, for example, the cube relay is marginal and allowing enough current to operate the solenoid when removed from the pump, but not enough to actually move the internal mechanism.


I believe there are four of the cube relays; Run, Shutdown, Pre-heat, and Start. Try swapping the Run and Pre-heat relays. Then see if you get fuel at the injectors while cranking with the override switch engaged.


Also check the ground wire connection on the generator end, typically on the side below the junction box. I'm not positive about this particular model, but typically there is a 10mm bolt securing a few ground wires to the chassis. Check that to be sure it's clean and tight. They tend to work loose. Maybe the fuel solenoid ground is marginal, and preventing it from turning on fuel. It's energize-to-run, so without it working, you won't get any fuel out of the injection pump, exactly like you are seeing.

 

[Msamsen]

I understand that you have tested the shutoff solenoid when removed from the injection pump, and see it moving. At the same time, everything you describe is consistent with a shutoff solenoid that is not operating correctly. So I think I'd go back over that again.


Some sort of internal injection pump failure that causes the generator to go from running fine to no-start seems very unlikely. On the other hand, the little cube solenoids do go bad over time, contacts get pitted, and current slow can be restricted. Perhaps, for example, the cube relay is marginal and allowing enough current to operate the solenoid when removed from the pump, but not enough to actually move the internal mechanism.


I believe there are four of the cube relays; Run, Shutdown, Pre-heat, and Start. Try swapping the Run and Pre-heat relays. Then see if you get fuel at the injectors while cranking with the override switch engaged.


Also check the ground wire connection on the generator end, typically on the side below the junction box. I'm not positive about this particular model, but typically there is a 10mm bolt securing a few ground wires to the chassis. Check that to be sure it's clean and tight. They tend to work loose. Maybe the fuel solenoid ground is marginal, and preventing it from turning on fuel. It's energize-to-run, so without it working, you won't get any fuel out of the injection pump, exactly like you are seeing.[/QUOTE


Hi Twistedtree,
Thanks for digging into this!

The solenoid pops in and out with the override switch activated and I can feel the valve (or sleeve) inside moving in and out when i push it with a small tool. Im not sure what else to check there. I may throw a new one at it just to make sure.
I did swap out the cube relays to different positions and I am getting start and solenoid operation either way.
Also I may try pulling the delivery valve assemblies on the IP to see if there is anything obstructing them.

 

[Lepke]

It appears that the fuel stops at the injector pump. Is there a plate with the make, model, and serial number? If so could you post it.
It sounds like a failed fuel stop solenoid. You have pressure to the pump but not to the injectors. When you bleed the injector tubes, if you loosen all the top nuts, place rags to catch fuel, and crank the engine, it won't start because the reduced pressure isn't enough to open any of the injectors. Crank until you have solid fuel. No fuel, stop solenoid bad or internal injector pump failure.

 

[johnrupp]

Check for obstructions/air in the return line.

John

 

[Circumnavigator]

I agree that it sounds like a fuel solenoid problem, but if I understand the responses above, it has been confirmed that the solenoid is pulling in when energized. (I've told this story before -- the two 9kW NL units we put in Fintry were purchased new as 24V units. Turns out they were converted from 12V at NL's Andover branch and the mechanic forgot to replace the fuel solenoids. They lasted 300 hours running on 2x voltage. I should add that I still believe in NL -- Morning Light has an NL 8kW generator and a Lugger 1066H main).


We took a 5kW NL around the world. I never had to bleed it -- it was self bleeding.


The suggestion to check the wiring box grounding is good -- I had that problem once. If the ground isn't good, the genset won't run.


I'm grasping at straws now, but have you checked the air supply? Is the filter clean? Is it possible something has been sucked into the air intake?


Jim


Sweetwater -- Swan 57 sloop on which we circumnavigated 1995-98
Fintry -- x Royal Navy Fleet Tender -- owned 2003-2022, 20,000 miles including trans-Atlantic
Morning Light -- Webbers Cove 42 single screw trawler 2021- ?

 

[MaDehn]

Two possibilities come to mind. Some engines have a small filter right at the injector pump. This may be clogged. The other piece is that some injector pumps have separate bleed screws on the pump body. My perkins is this way. You can get fuel right to the injector pump but get no fuel out of the injectors because there is a bubble of air in the high pressure pump. This bubble just compresses time and again never getting enough pressure to pop the injector. Look for a bleed screw on the body of the pump. If there is none then remove the line from the injector itself and crank the engine. From your symtoms l really think you have some air in your high pressure pump.

 

[Msamsen]

I agree that it sounds like a fuel solenoid problem, but if I understand the responses above, it has been confirmed that the solenoid is pulling in when energized. (I've told this story before -- the two 9kW NL units we put in Fintry were purchased new as 24V units. Turns out they were converted from 12V at NL's Andover branch and the mechanic forgot to replace the fuel solenoids. They lasted 300 hours running on 2x voltage. I should add that I still believe in NL -- Morning Light has an NL 8kW generator and a Lugger 1066H main).


We took a 5kW NL around the world. I never had to bleed it -- it was self bleeding.


The suggestion to check the wiring box grounding is good -- I had that problem once. If the ground isn't good, the genset won't run.


I'm grasping at straws now, but have you checked the air supply? Is the filter clean? Is it possible something has been sucked into the air intake?


Jim


Sweetwater -- Swan 57 sloop on which we circumnavigated 1995-98
Fintry -- x Royal Navy Fleet Tender -- owned 2003-2022, 20,000 miles including trans-Atlantic
Morning Light -- Webbers Cove 42 single screw trawler 2021- ?

Thank you for the tip!
And yes the solenoid retracts when energized.
I will check that grounding tomorrow!

 

[Msamsen]

Two possibilities come to mind. Some engines have a small filter right at the injector pump. This may be clogged. The other piece is that some injector pumps have separate bleed screws on the pump body. My perkins is this way. You can get fuel right to the injector pump but get no fuel out of the injectors because there is a bubble of air in the high pressure pump. This bubble just compresses time and again never getting enough pressure to pop the injector. Look for a bleed screw on the body of the pump. If there is none then remove the line from the injector itself and crank the engine. From your symtoms l really think you have some air in your high pressure pump.

I will be checking that pump out tomorrow. It really seems like thats whats going on. Thanks!