Just Purchased my first MEP803A!

[Guyfang]

Mweiss wrote:

Hi Rich, received the gauge today and installed it. Unfortunately, still the same result. Barely moves when the battery is charging. There is only 2-5mV across the gauge (an amp clamp on the battery cable shows more than 8 amps going into the battery), which indicated to me that it is not a gauge problem at all. It's something further back. I tested the old gauge on the bench. (You do this now? I suggested you do this at least twice before. This being done a long time ago would have been a big help in troubleshooting.) I found that it reads full scale with 50 mV across it. The generator is sending about 2mV to the meter, which is why it isn't giving much of a reading. Maybe if somebody knows why, it might be a simple wiring error, but I have not the time to delve into those diagrams and try to sort out where the unlabeled wires should be connected. (Actually the wires are numbered. And easily readable if you take the time to look. I know, you dont have time to look. The Positive side of the meter has the wire # 159A, and the Negitive side is 158A. They both terminate at MT4. Wire # 159A goes to MT4-2, and Wire #158A at MT4-3. After carefully removing the Negitive cable from the battery, left side of the gen set, I would unhook both wires at M4 and MT4. Ohm them out, starting at the MT4. Then get a magnifying glass so you can read the wire numbers and hook them back up. Then repeat this procedure at the at M4. Check the wire connectors, on all 4 ends. Also look at MT4. Make sure the link between terminals 2 & 3 is good.



Then as you can see below, You need to check the wire going from MT4-1 to FU1-1. That will be wire # 112B. Then check from FU1-2. wire # 180A . The wire 180A goes through J6/P6-27 and changes wire numbers to 180C. That wire terminates at G1. G1 is the battery charging alternator.







I would have thought that given the number of units you've processed, that a gauge not indicating like the rest of the units would have caught your attention. After a reset, one would at least expect all the gauges to be working.

Anyway, given that I can't see any number markings on the wires to the meter, I have no way to trace them out without cutting apart the wiring harness and separating the wires physically and following each to it's destination. I don't have the time to bother with that. (See above) And I shouldn't, at the price I paid.

I rejected the cheaper, local generator because the fuel gauge didn't work and I don't know how complicated it would be to fix that and the guy didn't seem interested in fixing it before selling plus he would not come down on price. Hence, I considered it worth the extra money to get 100% working unit from you. I was not expecting a "fixer-upper".

While I appreciate your generosity with the shipping and the trailer and sending out the replacement gauge, I was expecting the unit to be 100% functional at that price. If I were forty years younger and had energy, eyesight and time to fix mechanical stuff, I could have bought a much cheaper unit and worked on repairing it myself, but I don't have much time left, nor the stamina and vision to be doing repairs. I bought this particular unit so that my wife could easily operate it after I'm gone.

Sorry if I sound grouchy. It's been a terrible year, all around.

 

[rickf]

Holy Christ!!!!! The man sent you a known working gauge and you are still bashing him!!!! This is not cranky, this is evil. This is evil we do not need on this forum in my opinion, for what that matters. You are someone that will not take the time to diagnose something correctly by the book, you want others to do it for you. You bought a used genset, NOT NEW, and on top of that it is at least 20 years old I am sure. Why didn't you just buy a new commercially available set that would have had a warranty? If you are in such bad condition you certainly should not have bought a generator that required young able bodied men to keep it maintained and running. There is absolutely nothing mechanical out there and any shape or form that does not break. And in your position you need something that is covered by a warranty and that will have someone qualified to work on that unit come out and fix it if it goes bad.
I am sure I am going to get slapped for this post but I am also sure I am not the only one that sees it this way. I am just the one to speak up. I certainly hope you send that gauge back now that you know your gauge was in fact good. And have you given any thought to the fact that the gauge is not showing a huge charge because it is not receiving a huge charge due to the new batteries?

 

[Light in the Dark]

Mark its pretty obvious to me now (in hindsight) that this isn't the right solution for your needs. As others have said, you would be better served with a machine that is backed by a servicing dealer and a warranty. I suggest you offer the machine up for sale locally, and get into something better suited to your current and future needs. This isn't it. It should be an easy sale, as I found homes for (3) identical units in the last 6 weeks at this same exorbitant 'price I paid'.

If your gauge is fine (which I was sure it was as said in previous posts in this thread, but in good faith sent down another) I would appreciate you returning my gauge to me.

I wish you luck in doing more research for a more hands-off solution for your unique installation needs.

 

[Mweiss]

I did say in post #70 that there was only 2mV across the gauge and I suspected the problem was never the gauge itself. You assumed it was the gauge and, without consulting with me, sent me another gauge for a problem that is elsewhere in the system.

Where are these numbers on the wires? I see no labels on any of the wires:


Where is MT4 physically located? It looks like my options are to ignore the meter reading and assume the battery is charging, or cut all these tie wraps and separate the wires so I can physically follow them back to their destinations. I don't have the time or energy for that.

If I could afford $20,000 for a new commercial generator with service contract, I would, but on $1,067 a month social security pension, I cannot. My understanding is that a "reset" unit has been completely rebuilt and should be good for a long time. Perhaps I was mistaken, but that's how I read it.

I could have gotten one of those $1200 auction units and had it shipped up here for another $1000, if I were willing to gamble whether it worked or I needed to overhaul it myself. In a past life, I could have.

I'll reinstall my original meter and repack yours. but since I did not ask you to send it, the return postage cost should be on you. I'll have to arrange for someone to drive it down to the post office at their convenience. Send me a paid return shipping label and I'll get it back to you in the next couple of weeks depending on when my wife goes to the post office next.

 

[FarmingSmallKubota]

I have been following this thread for some time now and i can't take it anymore. I have heard about this would have should have bought this other generator deal to many times and don't really care anymore.I will stop reading/responding to this thread as this will never go anywhere. As I am not a moderator i can't lock the thread and forget about it so i will just quit reading. Too many people have tried to help here and i dont think there is much use anymore in trying. Thanks to all of the members who have tried to help here and helped in the past couple of years to get me to the point I am at with these generators I appreciate your time.

 

[rickf]

I am sure I am one of those you are referring to and no, I am not laughing. I am 73 years and have had a couple heart attacks myself. I have also owned my own business as a repair facility which did quite well. I am very well aware of customer service. All of that said, you yourself said in the beginning that the price of those same sets that you got was much, much higher where you are. So you know you got a very good deal. Plus delivery and a free trailer. I will not go into that. We have all tried to help you and all you do is say you do not have the time to do any of this. And yet you cannot get out to the post office. We pick up on this stuff and it has nothing to do with age, nor old boys club. We all know what these sets are worth but we are also ALL military equipment collectors. And as such we also know that this stuff does not last forever. I have several generators but I bought them back when the price was low. Two 002's and an 003. I paid 300 and 350 for the 002's and just recently I paid 1600 for an 003. But I also had to drive 1800 miles round trip to get it. This is not a lack of sympathy for your situation, we feel for you but at the same time we are all offended by your attitude over this whole thing. I suggested putting in a digital volt meter that would solve the problem and be much, much more accurate than the factory gauge. The military makes everything they have super overly complicated. My frequency meters did not work on two of my sets so I replaced them with off the shelf electronic ones for 1/4 of the price. And half the wiring.
Speaking of wiring, the wire numbers are printed on the insulation of the wiring. I am sorry I got so nasty in my last post but that is pretty much what you are giving us. I wish you the best of luck with your machine. There is nothing more I can offer to help you. But we are not the enemy. Soften up some and you will get more help.

 

[Guyfang]

The numbers are on the wires. The MT4 is plainly marked. This is my last post here, other that in a moderator function.

 

[Guyfang]

There will be no more finger pointing, name calling or muck raking. Concentrate on the generator and its repair, and nothing else.

 

[swbradley1]

And now I get to watch over this for a little while.

 

[Mweiss]

All I'm trying to say is that it is reasonable to know the operational status of what you are selling and be up front about any malfunctions.

Throwing in a digital meter isn't going to solve the problem if the voltage to the meter is missing. I've said this in post 60 and again in later posts. The meter is 50mV full scale, which is normal for a meter of this type. But the genset only sends 2mV to the terminals of the meter.

I looked in the area behind the panel and did not see anything marked MT4. Or is it in the engine bay?

Even with my magnified reading glasses, I was unable to make out any numbers on the wiring. If there are numbers on there, they are very small, along the side of less than 4 pts in size.

I thank the moderators for clamping down on the off-topic vitriol.

 

[2Pbfeet]

If you purchase a digital ammeter that has installation instructions, and follow those instructions, it is likely to work. Most will come with their own shunts or sensors, bypassing the the original MEP-803A wiring.

That is a fix.

It most certainly sidesteps whatever the underlying issue in your generator is. Whether that issue is important to the well being and longevity of your unit is impossible to call. Others have suggested the benefits to tracking the problem down. If it were me, I would sit down, and read all of the 803 manuals as many times as it took until I understood them, and then come back to the generator. In the grand scheme of things, they are quite good manuals, with a great deal of information.

At some level, if you aren't having fun fixing and maintaining your unit, there are a solutions beyond putting in a digital ammeter: ignore the original ammeter, or sell the generator. If you can't afford another, and I can understand that, there are candles and flashlights that go a long way in my book.

I, for one, am grateful to those here who volunteer their time and knowledge to help others. There are many here who have probably forgotten more about these units than I will ever learn, and I am very thankful to have them share their hard earned, and hard learned wisdom. Thank you all.

All the best,

2Pbfeet

 

[patracy]

I thank the moderators for clamping down on the off-topic vitriol.

I have edited your post to likewise remove the vitriol.

 

[Mweiss]

I probed around today, disconnected the meter wires and ohmmeter verified they actually go to the shunt (with them connected, one wire was always 0.5 ohms).

Then I fired up the generator and noted that I have about 27 V on the FU1. It's the same voltage on both sides of the shunt. So the round symbol, designated "G2 EXC" guessing G2 is "generator". So not enough voltage is dropping across MT4, despite over 11 amps flowing into the battery at the battery positive terminal.

The next thing I did was measure with a current clamp, the current going through MT4 with engine running. I got 11.9 amps reading.

So then I measured across MT4 the DC voltage and got 0.002 volt or 2 mV. So the shunt has almost 12 amps going through it, but it is dropping just 2 mV. I calculate the resistance of the shunt at 24 milliohms, which sounds about right for a piece of brass strip with notches cut into it. But based on a 50mV full scale meter type, the shunt should be 250 milliohms.

Starting to look like a factory error.. possibly the MT4 shut is the wrong value.

 

[kloppk]

Starting to look like a factory error.. possibly the MT4 shut is the wrong value.

I started suspecting it may have the wrong or defective shunt in it.
Usually when they go bad, they totally open up.

 

[Mweiss]

My thinking is leaning toward wrong shunt rather than defective. Short of corrosion, not much can go wrong with a 1/4" wide strip of brass.