#2 MEP 805B oh the joys

[155mm]

Started on #2 805B today, replaced the mandatory John Deere washers on all the fuel lines, primed it up, and it started like a champ. Now the issue is having negative oil pressure, negative amp draw, 2 amps draw on all 3 legs with the engine not running, and it shows the battle short switch is on.

Cant get photos to upload

 

[baxter462]

If it also shows the fuel level at 107%, that means the CIM and I/O modules aren't communicating. Check the p20 ribbon connector at the I/O module and the p27 ribbon connector on the CIM. You can install the CIM validation program on a pc with a serial port, disconnect p20, and connect the ribbon cable to the pc serial port using a cable and null modem. If the CIM values cycle and various faults are shown, the CIM and ribbon cable are good and the I/O module isn't sending the data. Otherwise, check the ribbon cable circuits between p20 and p27 using an ohm meter. If they check out, it is a problem in the CIM, most likely the internal ribbon cable or connection onto the motherboard.

Was this the CIM that was full of water? If so, I highly suspect the internal ribbon cable is corroded.

 

[155mm]

Was this the CIM that was full of water? If so, I highly suspect the internal ribbon cable is corroded.

This is #2, hasnt been wet, tomorrow will be the day to check ribbon cables.

 

[baxter462]

Out of curiosity, is the network failure light on?

 

[155mm]

no, its off, but i also did not push to test to verify it works

 

[baxter462]

The network failure light should come on when you first turn the main switch on, and should turn off when the CIM reaches a certain point in the boot up process. If it never turns on, but does work when you press it, there may be an I/O module issue. I'll have to read more about it.

Also, if the network failure light does behave properly, (turns on at first, then goes out as the cim boots), I believe this would indicate the CIM is sending data to the I/O module, and the I/O module is receiving that data. Since the communication between those two modules is rs232, there are separate rx as tx circuits, so the tx circuit from the I/O module (rx for the CIM) could be open or otherwise faulted. In other words, it would be possible for the CIM to send data to the I/O module, but not vice versa if that circuit in the ribbon cable or a corresponding pin in p20 or p27 has a problem.

I'll read more about it and see if I can come up with any other ideas.

 

[155mm]

only lights that are on in the box are the L1 and DC power.... push to test light is inop. Will work on it more tomorrow in the light

 

[baxter462]

That should give you a good diagnostic direction to go.

 

[155mm]

Thanks to patracy, i can post photos now, the file has to be under 2mb, here is the screen shot i was trying to post earlier.

 

[baxter462]

Yeah, I powered up an old CIM by itself on my workbench and those are the exact same readings. It is for sure not communicating with the I/O module. I haven't had a chance to look at the TM yet, but the inop network failure light makes me think something isn't getting powered up (such as the I/O module). I'm not so inclined to think it is a ribbon cable problem anymore given the behavior of the network failure light. I'm leaning more towards a power distribution issue (something isn't getting powered properly up from the main switch S1). I'd get out a schematic and do some quick testing of S1 and related wiring.

Maybe Guyfang will chime in with some additional info.

 

[baxter462]

I just quickly glanced at the schematic, and yes, the network failure light is powered up from S1 for the "push to test" feature through a terminal block that feeds a bunch of other stuff. I suspect if you track down the power feed issue causing the network failure light to not work when pressed, you'll resolve the entire issue. Hopefully it is something as simple as a bad S1 (main) switch, or poor connection at the switch or terminal block.

 

[Guyfang]

Are the batteries fully charged? The CIM also can give you strange problems if the batteries are not at a full charge. I had a problem that drove me mad, due to a battery that was sub par, (10.5 to 11 volts) and would lose its charge after a period of idleness. When we started it. it acted strange, all kinds of faults. The battery charging circuit would after a long time, charge up the battery, it would all of the sudden "get better", then stop working right, later.

I have to admit, it sounds like a cable problem, loose, dirty/corroded contacts. Or, the problem could be that the CIM isn't communicating with the I/O, due to the inability of the I/O to accept the signal. Sadly, it's hard to check this kind of thing without proper test equipment. You do have a second set to do "Controlled Substitution".

Crack the CIM open and see if its moist.

These sets do not vibrate much, so I would look for loose connections/broken connections, only when all else fails.

What kind of S-1 do you have? If it's the version 1 or 2, that could be a problem. If it version 3, well, I have never seen one go bad. Never. Doesn't mean it can't, but if it is, we should mount it on a wall someplace. Take a good look at the connectors on S-1. Sometimes they crack, passing voltage, but not amperage.

These are just some quick ideas/thoughts. I have to run to Bamberg to get my ears looked at again. Then the doc is going to tell me I am hard hearing. Been wearing hearing aids for a long time. I don't know if I can take the shock of hearing his diagnoses. May have to stop and have a beer on the way home. Will look in later when I get back. Driving gives me time to think about it.

 

[155mm]

The batteries are full plus i have the slave hooked up to a running 5T. The io box was not skrewed to the wall so i remounted it. Found 2 skrews loose, one on s1, one on tb4. I dont know what version of s1 i have, how do i know which one i have? Opened cim, it was dry. More to come as i work

 

[baxter462]

Hmm, that's suspicious, like a technician swapped the I/O module in an attempt do solve the problem, or they used your generator for parts to fix another unit. Let's hope not.

Still, I think you should investigate why the network failure light doesn't illuminate when you press it. I think once you solve that issue, you'll also solve the main problem.

Good luck

 

[155mm]

Oh, the network light works properly now after tightening the skrews

 

[baxter462]

Oh, good! I missed the part about the loose screws on s1 and tb4 in the previous post. So, is it fixed?

 

[155mm]

Got a heartbeat on io, oil psi still shows-24, no dc power light on speed control unit. Amp gauge works kindof, water temp works

 

[Guyfang]

Almost all the components are grounded twice. Mounting screws, and through the wire harness.

Version one, S-1 switch was round and plastic. Blue in color.
Version two, S-1 was square, and plastic. Blue in color.
Version three, S-1 was round, gray, (kinda) and made of plastic and metal. The shaft is metal. Much more robust.

Send a picture. One of these days we should do a sticky showing the versions.

Good that the heartbeat shows up! Start looking at the Trouble shooting diagram.

 

[155mm]

So i have v2

 

[baxter462]

Awesome, the cim and I/o module are talking to each other now. Just a little more troubleshooting and you'll have everything working.