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Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Yahoo Message Number: 50048
Ok, I pulled the solenoid on my Power Technology 7.0 Generator that will not continue to run if I release the start button.
It is a plunger type solenoid with three wires leading to it. I have instructions for testing a similar solenoid on a Kubota engine.

When I power the White and Black wires, the plunger retracts.
When I power the Red (positive) and Black (negative) wires and push the plunger in, it does not stay in.
So, I am guessing that the plunger shuts off the fuel rack when it is extended and allows fuel to flow when it is retracted.

The white wire is positive for the starting function?
The red wire is positive for running after the start button is released?
The plunger will not stay retracted in the red + black so the solenoid is not working.
Since this looks like a $175 solenoid, I'd like to verify my thinking.

Can anyone comment on the above results?

Dean

95 CC Magna 5280

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #1 –
Yahoo Message Number: 50050
Your thinking is correct. One coil in the solenoid is high-current and is used to initially 'pick' the solenoid and retract the plunger. The second coil is to 'hold' the solenoid plunger retracted and continually allow fuel to flow. That second coil takes much less current and is usually controlled by a 'run' relay or control circuit - depending on the setup. Low oil pressure, high water temp are some of the things that can turn off the run relay. Had to replace mine on the Cummins a few years back and your description of the problem is almost exactly what mine was - except mine was that hold coil heated up and gradually lost its ability to hold the solenoid retracted. This was a known problem and Cummins had a heavier-duty solenoid as a replacement that also required the mounting for it be changed out.

I'm not aware of these fuel solenoids working any other way.
Since you have the solenoid in your hand and can't get one of the coils to keep the solenoid in, you're heading to the parts dealer.

Incidentally, holding the start on for extended periods of time can overheat the coil and burn it out. There are generally safeguards against this (thermistors, oil pressure interlock, etc.) - not sure if they are employed on small diesel engines. However, if you have had hard starting problems where the 'pick' coil was active for a long time, that's probably what eventually caused the coil burnout.

Mike

'95 Magna 5266

Dean wrote:

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #2 –
Yahoo Message Number: 50057
Rats....I hate it when I am right and it then costs me money...
Mike, thank you for the excellent clarification and description. I pieced together the information from various places on the web, but did not know how to verify what I was doing. You solved that for me.
Especially helpful was the comment about low voltage for the run coil. I was getting only a 2.6V reading on that circuit and thought I had to have 12.6V there. So the final piece of the puzzle is resolved by your information.
Yes, I had a hard starting situation for awhile. Then it resolved but became an intermittent won't start scenario. Finally, intermittent disappeared and it just would not keep running at the release of the start button. I did disconnect all the sensors but that did not resolve the problem.
Now I have to source that solenoid. The number I am using is KUB17454-60010 which looks like about $130 shipped.

Again, thank you for the help...

Dean

95 Magna 5280

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #3 –
Yahoo Message Number: 50066
Hmmmmmm, Slight misunderstanding. I said 'much less current' on the run coil. The voltage should still be 12+V. Not sure what you were measuring and the effect the bad solenoid had on the circuit.

Mike

'95 Magna 5266

Dean wrote:

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #4 –
Yahoo Message Number: 50078
Mike, I disconnected the solenoid lead wire. I got 12V when pressing the start button on the Black and White wires which are the wires that cause the plunger to retract.
I measured 2.6V on the Black and Red wires when I pressed the start button. This I assumed would be the run coil wires.

It is a three wire solenoid.

Dean

95 Magna 5280

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #5 –
Yahoo Message Number: 50120
Here is an extract from a PowerTech manual that gives some detail on the run conditions:

ENGINE STARTING CONTROLS
1) Generator Main Switch must be in the ON position.
2) Hold Start/Stop Switch for 1 second and release.
3) Glow Plugs will preheat for 8 seconds. LED flashes slowly.
4) Preheating will cease during engine cranking cycle. LED continues flashing.
5) Engine begins an 8 seconds crank cycle, After 4 seconds of cranking the PT-ECU-63 will check

for an AC signal from the generator. If an AC signal is verified the engine will start and the LED

will remain ON during the normal run operation. If the AC signal is not verified the PT-ECU-63

will terminate the cranking cycle and LED will flash a fault code.
6) Starter disengages immediately after engine run is verified.
7) PT-ECU-63 deactivates the Low Oil Pressure and High Water Temperature Switches for 6

seconds, this will assure oil pressure build-up time. If oil pressure does not build-up the engine will immediately shut down and go into a fault mode. Likewise for a high temperature situation.
8) If engine will not start on the first attempt the PT-ECU-63 will initiate the start cycle 2 more times before going into a fault mode. Glow Plugs will preheat for 8 seconds per attempt. Engine will
crank for 8 seconds per attempt.
9) To shut down the engine under normal operations, hold the Start/Stop Switch for 1 second and release.

10) If a fault occurs turn Generator Main Switch OFF and then ON to reset PT-ECU-63.

CHECKING ENGINE AFTER STARTING

1) Allow the engine to warm up 3 to 5 minutes before applying a load.
In colder climates allow a few
extra minutes longer.
2) Perform a visual inspection of all areas of the engine and generator.
3) Listen for any abnormal noises.
4) Check for any abnormal exhaust gases.

STOPPING THE ENGINE

It is recommended to disconnect or reduce the power load from the generator before shutting down the engine. Then follow the steps outlined above for normal shut down.
NOTE: The PT-ECU-63 is designed to operate on 12V DC power. In a low battery situation the

PT-ECU-63 may not initiate the normal cranking cycle. To start the generator you can press and

hold the Start/Stop Switch for approximately 10 seconds or until the engine starts. Once the

engine starts the PT-ECU-63 will resume normal operations. If this situation re-occurs, charge or
replace the battery.

IMPORTANT: Damage to the Starter Motor, Starter Solenoid, Run Solenoid or any generator component

due to excessive or prolonged starting attempts attributed to an external Low Battery Control Monitoring or Auto-Start System will not be covered by the Power Technology Southeast, Inc. Limited Warranty.
Mike

'95 Magna 5266

Dean wrote:

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #6 –
Yahoo Message Number: 50140
I have read the below description somewhere but not in my limited edition manual. Of course my/our Powertech does run with the AC switch/breaker off, has no Led light, provides no test codes, and has a hold for 10/15 second preheat instruction. So I lost interest at that time.
Obviously newer models have some improvements that simplify the analysis.
On another topic, does your electric fuel pump rapidly click during the preheat cycle? I have assumed that mine should, and I did have fuel at the #3 injector along with 12.6V at the glow plugs.

Dean

95 Magna 5280

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #7 –
Yahoo Message Number: 50142
Yup. Very audible click from the pump.

Mike Cebula
'95 Magna 5266

Dean wrote:

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #8 –
Yahoo Message Number: 50144
Okay, you stated if you put 12 volts to the red wire it will not hold the solenoid in the run position. IF this is the case the solenoid as failed. The solenoids usually fail from repeated attempts to start, thus overheating the solenoids. They are very sensitive to overheating, the start or pull in coil will overheat pretty quick, then is cooks the solenoid... The last check you can do is disconnect the red wire, hold in the run solenoid manually start unit measure voltage a the red wire that is disconnected from the solenoid. If it has 12 volts that tells you the safety circuits are all working correctly.

Mikee

Re: Fuel Shutdown Solenoid on Power Technology 7.0K Generator

Reply #9 –
Yahoo Message Number: 50294
Update....I installed the new $117 solenoid this pm. No significant change in starting. The fuel pump has a more "solid" sound the engine fires immediately, but releasing the start switch shuts it down.

1. The solenoid install seems to be just push it into the tight hole and presumably it will mate with the fuel rack?
2. I have not done the test that Mikee suggested since the solenoid already was shipped and I hoped.....................but I will try it tomorrow.

3. I disconnected the wires from the oil and coolant sensors. No effect. Also disconnected the remote start/stop harness.

4. That would leave the run relay as a possible culprit?

The symptoms "would not run. Wait several hours. Then starts and runs for a several extended period events. Shut down intentionally. Now will not run" sounds like a broken or loose wire. But I have yet to find one.

Frustrating...

Dean

95 Magna 5280