MEP 007b engine electrical issues

[jmenende]

There is a small diode next to the day tank screwed onto a bracket with 2 flat head screws. I replaced that part and it fixed my electrical issue with the daytank float. Luckily i had a spare 007b in the yard and pulled it from there. The parts seems simple enough to be repaired cause i doubt you will find a new one.

 

[SLTRAM98]

I replaced these diodes, located on a bracket to the left (front) side of the day tank. Per the TM, they are for radio interference; either way mine were broke/corroded. Still no power though.

Is this the same bracket you are talking about?

 

[SLTRAM98]

More pictures of the diodes CR27/28 I replaced.

 

[jmenende]

More pictures of the diodes CR27/28 I replaced.

Thats the one.

 

[SLTRAM98]

Ok, going through the TM electrical diagram A27-TB3 has the pump connections before they go to A5 (behind the main front panel). Does anyone know where they hid A27/TB3?

I will start diagnosing A5 later today if I can verify continuity from A5 terminals to the pumps. Still looking for how others solved this, thank you

 

[Guyfang]

I do have the TM's, I have read them -12 & -24 (I am still at a loss as to why there is a day tank at all on this genset). ( Gen sets larger than 3 KW have a day tank. Or a fuel system that funtions like one. Its simple. If the gen set senses that the tank is almost empty, the set shuts down for low fuel. Reason, so you do not have to go through the circle jerk of bleeding the fuel system. Some gen set do not do this easily. I spoke with Cat mechanic shop and they say, bypass the day tank and pump straight to the engine if possible since any excess will bypass internal check and return to the tank. (Before I did this, I would troubleshoot the problem. Find out what is wrong and fix it. Hooking up stuff to bypass the system seems to me to be counter productive. ) Does anyone know why the military thought a 5 min run time tank on this unit was actually needed? (See above answer. And yes I do. It would not matter if its five min. or 5 hours. Low, is low. As long as you keep the fuel system supplied with fuel, its a non problem.)

I have pulled the float out of day tank, checked it over visually, it looks good, I do not know how to verify function though aside from sliding the floats up and down in 'call for fuel' position and it changed nothing. (In the TM is a test procedure. )

The low oil pressure dummy light is the only one that stays on; ( all the time?) all light up when you hit the test switch as expected.

Genset was running when it quit (why did it quit?) 11 years ago, then sat in a barn till now.

No voltage at pump wires, already checked. Is there a terminal block that these pump wires run to aside from the CR27/28 TB?

What else do you need to know? I felt like starting a new thread was not useful since this thread is exactly what I am experiencing however I will do whatever is needed. (You have no idea if its the same problem. All the comments before you jumped in, mean nothing, and confuse those who want to help.)

Thank you



First, see if the pumps work. Remove J5 plug. Take a wire and run it from 24 VDC+. to first pin D and then pin F. Do both pumps run?

 

[Guyfang]

No. CR27 is not for radio interference.

 

[SLTRAM98]

Guyfang, I started a new posts with more information from my work on her today. Link below, thank you.

MEP-007B DC Relay Control Issue

Looking for some help on this one. I have a MEP-007B with the Cat 3306 engine 100kw generator. Has 1000 hrs on it. Genset background: - Has not been running in roughly 11 years. - Was in use when it quit, the guys I got it from had no idea what was wrong with it. - Barn stored after it quit...

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