MEP-802A will not crank (coolant high temp light coming on)

[polk738]

Simply unscrew it. Grab it with your hand and unscrew it.

Got it, it was really on there, checked continuity, it was good from S10 terminal 3 to pin 14

J7 pin 14 to s17 terminal 1, don't know which one terminal 1 is, but both terminals had continuity, bottom terminal had a bit more resistance but not a large amount maybe 2-5 ohms?

 

[Guyfang]

Did you look at the plug? I mean LOOK. With a light. Look into the pins. Then lay on your back, stick your head inside the set and look at the plug?

 

[polk738]

Hows this?

 

[Guyfang]

That looks good. And the plug that goes in it?

 

[kloppk]

Stop
It looks like a possible issue with Dead Crank switch tho they seldom fail.
Away from my computer so I can't look things up at the moment.

 

[polk738]

That looks good. And the plug that goes in it?

It looks good from what I can see, no pins pushed in, burnt or damaged etc etc

 

[polk738]

Stop
It looks like a possible issue with Dead Crank switch tho they seldom fail.
Away from my computer so I can't look things up at the moment.

Yeah? I don't really see how that affects the power state of the generator, because now I don't get any working functions, no panel lights, clicking relays, solenoids or anything, the dead crank does still work but that is basically it, it's like the E-stop is engaged when in actuality it isn't

 

[Guyfang]

Is the S10 in the "Normal" Position? Its a three position switch.
Off is the middle. The engine can NOT turn over.
Normal is just what it says. Thats the way it should be.
Crank is the down position, (I think) and that should just turn the engine over but NOT let it start.

 

[polk738]

Is the S10 in the "Normal" Position? Its a three position switch.
Off is the middle. The engine can NOT turn over.
Normal is just what it says. Thats the way it should be.
Crank is the down position, (I think) and that should just turn the engine over but NOT let it start.

Yes, it's in normal

 

[kloppk]

S10 terminal 3: 23V in off position .5V in start/run position

Terminal 3 of S10 should always have about 24 volts on it when it's set to NORMAL.
You posted it drops from 23 to 0.5 volts when you move S1 to Start/Run. That's a problem.

Check S10 terminal 2 and see if too drops from 23 to 0.5 volts when S1 put in Start/Run.
If it does drop to 0.5 volts then the culprit is probably a bad CR1 diode. They fail frequently.
To verify this put a jumper across the two leads of CR1 and see if you can now engage the starter with S1. If the starter engages via S1 then CR1 is the issue.
Diode CR1 is on the parts panel on the far left of the back wall behind the gauge panel.

 

[polk738]

Terminal 3 of S10 should always have about 24 volts on it when it's set to NORMAL.
You posted it drops from 23 to 0.5 volts when you move S1 to Start/Run. That's a problem.

Check S10 terminal 2 and see if too drops from 23 to 0.5 volts when S1 put in Start/Run.
If it does drop to 0.5 volts then the culprit is probably a bad CR1 diode. They fail frequently.
To verify this put a jumper across the two leads of CR1 and see if you can now engage the starter with S1. If the starter engages via S1 then CR1 is the issue.

S10 terminal 2 dropped from 23V to .5 volt when I engaged the S1 to start/run

jumped the CR1 diode still nothing, no crank, no power, no panel lights, etc etc, nothing

 

[Guyfang]

Are you sure your batteries are good? When you turn S1 to the start position, the pre-heat draws a LOT of amperage.

Do the panel lights come on? If so, turn them on and then try and start the set. Do they dim/go out?

 

[polk738]

Are you sure your batteries are good? When you turn S1 to the start position, the pre-heat draws a LOT of amperage.

Do the panel lights come on? If so, turn them on and then try and start the set. Do they dim/go out?

Yes they are fully charged and I load tested them several days ago, no the panel lights do not come on

 

[kloppk]

OK, same conditions, check voltages at both big terminals of MT4. It's the shunt mounted in the front right corner of the "floor" behind the gauge panel.

 

[polk738]

OK, same conditions, check voltages at both big terminals of MT4. It's the shunt mounted in the front right corner of the "floor" behind the gauge panel.

Good morning guys, MT4 Shunt both big terminals: 23.5Vs with S1 in off, 23.5Vs in prime/run and start

 

[kloppk]

Check that diode CR1 has about 24 volts on each lead under the test conditions. Does it?

If it does, then it appears to be an issue getting 24 volts from CR1 terminal 1 to the S10 Dead Crank switch terminal 2.
The path from CR1 terminal 1 to S10-2 is...
CR1 terminal 1 to J6-33 via wire 120B.
P6-33 to S10-2 via wire 120A.

Probably should disconnect P6 from J6 and inspect terminals 33 in both of them.
Also do continuity checks from CR1 to J6-33 and S10-2 to P6-33.

 

[polk738]

Check that diode CR1 has about 24 volts on each lead under the test conditions. Does it?

If it does, then it appears to be an issue getting 24 volts from CR1 terminal 1 to the S10 Dead Crank switch terminal 2.
The path from CR1 terminal 1 to S10-2 is...
CR1 terminal 1 to J6-33 via wire 120B.
P6-33 to S10-2 via wire 120A.

Probably should disconnect P6 from J6 and inspect terminals 33 in both of them.
Also do continuity checks from CR1 to J6-33 and S10-2 to P6-33.

CR1 diode: 0 volts on both leads in off/prime & run AND start

 

[kloppk]

I suspect you were not on the CR1 leads based on your other voltage measurements.
The labeling on the panel CR1 is mounted to can be confusing.

CR1 is circled in RED

 

[polk738]

You were right, I was checking the wrong one, I apologize for that

CR1 diode has 23.5Vs on both leads with no changes in off/prime & run and start

I'll inspect J6/P6 and post my findings

 

[polk738]

CR-1 diode (I don't know which one is terminal 1) left terminal to J6-33 OK , right terminal nothing

S10 terminal 2 to P6-33 okay

There was a slight bit of corrosion on pin 33 of J6 but it didn't seem like a significant amount to be causing the issue I currently have, there wasn't alot of resistance when I did the check. P6-33 had a slight amount as well, I cleaned both up with some electrical cleaner.