MEP-805B throttle actuator problem

[Don+23805]

Just found this forum. What a treasure trove of info!
My brother picked a practically new MEP-805B and used it for over a year. Then one day the engine just shut down. He thought it was out of fuel - nope. He's the mechanical guy; I'm supposed to be the electrical guy. We finally pinned it down to the fuel actuator valve isn't getting a signal. At first we thought it was just an on/off fuel solenoid, but later realized it's the business end of the governor. I can power the actuator separately and control engine speed. But can't get the automatic speed regulator to work. The magnetic rpm pickup must be working because the generator frequency is displayed on the CIM screen. We have the whole TM.
One thing I can't find is the Governor Control Power Relay. It's shown on the block diagram on page 1-20, and is referenced in paragraph 1.16.3.3 . It says that it is connected to the Fault System, but I can't find it on the wiring diagrams or schematic. Any help finding this would be most welcome.
I'm about to install a variable power supply with a front panel pot that will let us set engine speed. This will probably do as long as the load doesn't change too much, but Automatic would be lots better. Read many of the 805B posts, but nothing seems close enough.
TIA Don

 

[Guyfang]

If you can not find a wire diagram or schematic, you do not have all the TM's. Go to the TM forum in SS. All the TM's are there. TM9-6115-671-14 has schematics in it. What TM are you using for Troubleshooting?

 

[Don+23805]

Our TM is 9-6115-671-14 that came with the generator. It has the 4 foldout wiring diagrams at the back, but I don't see any reference there to the Governor Control Power Relay, either coil or contacts.
TIA Don

 

[Guyfang]

Whats the date on the TM, and is there any changes? I am using the latest TM, and there is no page 1-20

 

[Don+23805]

Mine is dated 1 July 2000 PCN 182 092491 00

When I open View attachment TM 9-6115-671-14 - Copy (1).pdf , it's only a single blank page.

And this one View attachment TM 9-6115-671-24P.pdf is completely different (and not much help).

 

[Guyfang]

Mine is dated 1 July 2000 PCN 182 092491 00

The above listed TM is way, way out of date. You should be using the 2012 TM. Its the one you can not open. The reason you can not open it is because its first off, coded "C", not for public distribution, and second, its bee "Copyrighted", so to say. It will not allow you to copy and forward it. I will dig into my junk, and see if I can come up with the TM you are using.

When I open View attachment TM 9-6115-671-14 - Copy (1).pdf , it's only a single blank page.

And this one View attachment TM 9-6115-671-24P.pdf is completely different (and not much help).

The 24P is a parts TM. Important, but not what you need right now.

 

[MrMikey4026]

The speed sensor controls the governor, the frequency meter reads the produced generator frequency. It has no control over the governor.
You should have a look at the speed sensor again.

 

[Guyfang]

Here is something not in the TM. Check out your LEDs on the backplane and Gov Control Unit.

Have you pulled the MPU out? You said it was good, but did you check it? Pull it out, clean it and reinstall, properly and test? Thank you Mikey. I never thought to ask, when I read your post.

 

[Don+23805]

Haven't touched the MPU. As I understand what you're saying is that it's SCU that is "the governor". And the CIM merely shows info from various sensors (MPU, CT's, etc). Since the CIM is showing the frequency as it changes, I figured the MPU was OK.
I printed out the 5 pages showing which LEDs should be on & when. Will take that out to The Farm today.
Ours is one of those units with the "insufficient CMOS voltage" LED always lit. From other posts, it appears that on most, there is no CMOS battery (I haven't found one) so it's not relevant.
Don

 

[155mm]

I had the plastic connector fail that connects he actuator to the harness, so i just cut it out and replaced with covered male/female connectors

 

[Don+23805]

Thanks, but we've checked continuity from the actuator to P5 (the backplane connecctor), so that's not it.

 

[mundy201]

Don, just curious if you ever figured out your issue? I have a 805B that basically did the same thing...Ran for about an hour with 18kw load, then shut down and now just cranks. I do not see the cranking light or speed sensor light on while cranking on the Speed Sensing unit(ESD5551) but before I move forward with replacing just wanted to see if you had any luck with MPU or Speed sending unit

 

[Guyfang]

Well, have you Inspected,tested, replaced and properly adjusted your MPU? Easiest way to to exclude it from the probable problem list.