Fuel pumps won't work

[Walt4653]

On my friends MEP 003 he was installing a tiny tach and he didn't disconnect battery before working on it, one of the wires grounded out and he heard a pop seems like it came from the control box , but not sure, I read a couple of threads and one was about the capacitors on the pumps, he removed the connections and hard wired but still no fuel pumps work, getting 24.8 v on the feed but fuel pumps still don't work, Does anyone have a idea what went wrong. Turns over, white smoke, no fuel pump noise, Pre-heat works, but I am lost.
Fuse near voltage reg ok,, can anyone help

Thanks walt

 

[Triple Jim]

Are you saying that the pump leads actually have 24.8V on them, measured at the connector right at the pumps, but they don't pump?

What wire was it that touched ground?

 

[Walt4653]

Are you saying that the pump leads actually have 24.8V on them, measured at the connector right at the pumps, but they don't pump?

Yes Jim , on the feed wire he gets 24.8 v but nothing turns on, he cut capacitors off, I presume the black rubber plug connections, on the other one he was only getting 4 volts , that why we read , cut the capacitors off, and it should work, on a previous thread. Is there a fuse or something I should be looking for..?
Walt, thanks Jim

 

[Walt4653]

Yes Jim , on the feed wire he gets 24.8 v but nothing turns on, he cut capacitors off, I presume the black rubber plug connections, on the other one he was only getting 4 volts , that why we read , cut the capacitors off, and it should work, on a previous thread. Is there a fuse or something I should be looking for..?
Walt, thanks Jim

The feed is showing 24.8 but the pumps don't turn on

 

[1800 Diesel]

On my friends MEP 003 he was installing a tiny tach and he didn't disconnect battery before working on it, one of the wires grounded out and he heard a pop seems like it came from the control box , but not sure, I read a couple of threads and one was about the capacitors on the pumps, he removed the connections and hard wired but still no fuel pumps work, getting 24.8 v on the feed but fuel pumps still don't work, Does anyone have a idea what went wrong. Turns over, white smoke, no fuel pump noise, Pre-heat works, but I am lost.
Fuse near voltage reg ok,, can anyone help

Thanks walt

Did you check to see if the DC breaker was tripped? It would be pushed out if tripped...though, come to think of it, I don't think the engine wouldn't turn over if that breaker were tripped... I've also come across bad wires on the pumps themselves...but not all three...other than that, he may have popped a connection underneath the blower housing...did you actually check voltage at the DC fuse holder?

 

[Triple Jim]

If you have 24.8 volts at the pump and it's not running, then all I can suggest is to check for continuity from the connector to the pump internals. Exactly what happened when you heard the pop noise and things quit working?

 

[Walt4653]

If you have 24.8 volts at the pump and it's not running, then all I can suggest is to check for continuity from the connector to the pump internals. Exactly what happened when you heard the pop noise and things quit working?

He tried to start it, and it turned over, white smoke coming out, no fuel pump noise. Dc breaker is ok, fuse next to fi ok, did not check wireing under blower cover, noise seemed to come from front of gen. He was installing tiny tach to fuel line and other wires. He let one slip and shorted, then heard pop noise from front. Is there a fuse for fuel pumps, and could I try a pos lead from battery to check fuel pumps? Without Shorting anything else.
walt

 

[Jimc]

Well you have the black rubber connector plug then the capacitor which is that 3" long x 1/2" dia tube then that wire goes to the pump. If he cut the cap out and has 24 volt directly where the wire goes to the pump then he needs to check the ground. The pumps ground through the case so the mounting bracket grounds to the frame. If that is good then the pump is toast

 

[LuckyDog]

Walt, this might sound silly....

After cutting the capacitor out of the circuit (both wire ends) Did he reconnect the wires?

I attached the schematic showing just the fuel pumps. Only the CB and switch are in the path. So, if it turns over chances are they are ok.

Try running the fuel pump hooked up just to the battery and Ground.

 

[Triple Jim]

Is there a fuse for fuel pumps, and could I try a pos lead from battery to check fuel pumps? Without Shorting anything else.
walt

You said you have 24V power at the fuel pumps, so I don't see a need to look for a fuse, run another wire to test, etc.. I think LuckyDog may be on to something. See if his suggestion helps. The capacitors are the feed-through type. Power goes in one end and out the other, continuing on to the pumps. The capacitor inside the metal housing is connected from that power line to ground, to reduce RF noise for nearby radios, etc.. If you cut the wires to one of the capacitors, the cut ends need to be connected to each other.