MEP-804a no start (no power to fuel shutoff solenoid), it DID run recently.

[TacMac2012]

I have a new to me 804a, when I got it home I put batteries in it and started it up, ran fine. I got it hooked up to the house and let it run under load for maybe an hour, no issues. Yesterday I went out to start it and it would crank but wouldn't start. I replaced the fuel filter (the spin-on) and then found the fuel primer pump seemed to be leaking, it also would not prime the system. I took the primer pump off my FLU-419 and installed it on the generator and primed the system, still no start....

That brings me to my current situation:

I ran jumper wires from the shutoff solenoid to the batteries, this allowed the unit to start up, but it was noticeable higher RPM than it should run at so I pulled the wires off the battery to shut it down (it ran like this less than 5 seconds).

I have looked at the wiring schematic but I can't determine what the shutoff solenoid is actually called, because they can't just call it something obvious (like "fuel shutoff solenoid").

I am going to download and look through some manuals (ugh) but was hoping someone had a similar issue they have already worked through.

Thanks

 

[TacMac2012]

Have I mentioned I hate looking through the manuals? I have been searching on liberated manuals but when I search for "MEP-804a" about 300 manuals come up. I am also hate when I download one, then spend time finding the troubleshooting section for it to tell me 'go to next level manual'. I also wish the wiring schematics on the panels actually made sense.

 

[155mm]

First thing I would do, adjust/verify the crank sensor is functional and in adjustment. That adjustment has been a cause of problems for alot of people, and its probably one of the easiest adjustments to do.




I wouldnt use jumper wires on the shutdown solonoid/ governor, if I were going to run the motor manually, I would take this big plug off the top, and use a skrew driver to manually open the IP, that way you dont overrev the motor with the gov. run wide open.





I will ponder on any other ez fixes while I drive today.

 

[155mm]

Have I mentioned I hate looking through the manuals? I have been searching on liberated manuals but when I search for "MEP-804a" about 300 manuals come up. I am also hate when I download one, then spend time finding the troubleshooting section for it to tell me 'go to next level manual'. I also wish the wiring schematics on the panels actually made sense.

mep 804a maunuals

http://www.liberatedmanuals.com/TM-9-6115-643-10.pdf

http://www.liberatedmanuals.com/TM-9-6115-643-24.pdf


isuzu motor manual
[url]http://www.liberatedmanuals.com/TM-9-2815-254-24.pdf

[/URL]

 

[TacMac2012]

So I assume the crank sensor just senses the rotation of the engine and then allows power to the shutoff? I will check it shortly, thank you. I won't be firing it up anymore, I basically just did that to confirm in my head that was the reason it would not start.

 

[TacMac2012]

I have done some searching on the crank sensor, can't find anything on it either. I did adjust it in to where it was barely off the flywheel gear. I found something in the manual to check the "internal crank relay test', checking the governor control, so that's next on the list.

 

[155mm]

 

[TacMac2012]

Well it runs now, but doesn't make power anymore...

I did the check in the picture below, I was not getting voltage at terminal 5, and voltage elsewhere was low when cranking, about 15 volts. I hooked up slave cables to see if that helped and although it didn't start the first time, it did start the next time I checked voltage at terminal 5?

So now to go out and do the checks for no power output, hopefully I didn't fry something when I ran it with the fuel shutoff jumped.

 

[155mm]

you may have to use a modified start, start the genny, hold start switch in start position until oil psi comes up, release start switch to run position, move start switch to start position again to flash the field. if everything is in working order, the starter should not reengage the flywheel.

 

[TacMac2012]

I just tested the magnetic pickup and adjusted it to 3.0 volts A/C. Still no voltage but at least I know that is correct now.

 

[TacMac2012]

you may have to use a modified start, start the genny, hold start switch in start position until oil psi comes up, release start switch to run position, move start switch to start position again to flash the field. if everything is in working order, the starter should not reengage the flywheel.

Just tried this, no luck. Also checked fuse beside voltage regulator. Also, the Hz gauge is not reading either, engine speed does change when turning the frequency knob though.

 

[Guyfang]

The hertz meter will not work as long as your main gen does not produce voltage. The voltage you can read on the terminals is exciter voltage.

The hertz adjust knob, ( you mean the knob under the control panel? Not the hertz adjust rheostat?) should not be used. That's the reason you have a electric governor and electric actuator, controlled by the hertz adjust rheostat.

 

[Guyfang]

I have a new to me 804a, when I got it home I put batteries in it and started it up, ran fine. I got it hooked up to the house and let it run under load for maybe an hour, no issues. Yesterday I went out to start it and it would crank but wouldn't start. I replaced the fuel filter (the spin-on) and then found the fuel primer pump seemed to be leaking, it also would not prime the system. I took the primer pump off my FLU-419 and installed it on the generator and primed the system, still no start....

That brings me to my current situation:

I ran jumper wires from the shutoff solenoid to the batteries, this allowed the unit to start up, but it was noticeable higher RPM than it should run at so I pulled the wires off the battery to shut it down (it ran like this less than 5 seconds).

I have looked at the wiring schematic but I can't determine what the shutoff solenoid is actually called, because they can't just call it something obvious (like "fuel shutoff solenoid").

I am going to download and look through some manuals (ugh) but was hoping someone had a similar issue they have already worked through.

Thanks

The fuel shut off is the electric governor actuator. Also called the A6. Or maybe it would be better to show us what you call a engine shut off. Then we can get on the same sheet of music.

 

[Guyfang]

Have I mentioned I hate looking through the manuals? I have been searching on liberated manuals but when I search for "MEP-804a" about 300 manuals come up. I am also hate when I download one, then spend time finding the troubleshooting section for it to tell me 'go to next level manual'. I also wish the wiring schematics on the panels actually made sense.

All the the manuals you need for your gen set are here in the technical manual forum.

 

[Guyfang]

So I assume the crank sensor just senses the rotation of the engine and then allows power to the shutoff? I will check it shortly, thank you. I won't be firing it up anymore, I basically just did that to confirm in my head that was the reason it would not start.

No. The MPU, magnetic pick up, senses how fast the engine is running. At a certain RPM, it cuts out the starter. Then it tells the governor to ramp up engine speed, by energizing the A6, electric governor actuator, as well as telling the volt regulator to allow the exciter to light off the main generator.

 

[TacMac2012]

The fuel shutoff is the governor actuator, I wasn't expecting an electronically controlled governor, I expected wrong... On the side of the engine connected to injector pump.

I have not adjusted anything behind the front panel, when I say I adjusted the Hz, I used the knob on the front of the panel for 'frequency'. When I ran it yesterday I had to adjust it to get to 60hz.

I have been going through the manuals. Did the first test on the voltage regulator (voltage from wire connected to terminal 1 to 3) and it did not have voltage, which if I understand correctly it should NOT have voltage. It is kind of odd you test the regulator to for 'bad' operation and not proper operation.

 

[Guyfang]

I have done some searching on the crank sensor, can't find anything on it either. I did adjust it in to where it was barely off the flywheel gear. I found something in the manual to check the "internal crank relay test', checking the governor control, so that's next on the list.

When you screwed the MPU back in, you should have screwed it into the bell housing until it hit the flywheel. Then back it off 3/4 turn. Then tighten the counter nut, hand tight. Use a multimeter to measure between the two wires, in the AC mode, while someone else turns the engine over with the S-10, dead crank switch. The MPU should read between 2.5 and 3.0 volts AC. You can turn the MPU carefully one way or another to get as close to 3.0 volts as possible. Then compleat the task. Tighten up the counter nut, without turning the MPU. Hook up the wires. This procedure should be in the -24 manual.

 

[Guyfang]

The fuel shutoff is the governor actuator, I wasn't expecting an electronically controlled governor, I expected wrong... On the side of the engine connected to injector pump.

I have not adjusted anything behind the front panel, when I say I adjusted the Hz, I used the knob on the front of the panel for 'frequency'. When I ran it yesterday I had to adjust it to get to 60hz.

I have been going through the manuals. Did the first test on the voltage regulator (voltage from wire connected to terminal 1 to 3) and it did not have voltage, which if I understand correctly it should NOT have voltage. It is kind of odd you test the regulator to for 'bad' operation and not proper operation.

Did you read 60 hertz on the meter? As I understood you, the meter didn't show anything?

 

[Guyfang]

Hey, 155, you and dieseladdict need to jump in here. It 24:05 and this old soldier needs to sleep!

 

[TacMac2012]

I tested the magnetic pickup as stated. Correct, Hz gauge reads nothing.