Ignition fuse keeps popping

I have a gradall g6-42P that pops the ignition fuse when the machine ignition is turned to acc. If i disconnect the purple wire from the top of the fuel shutoff solenoid it won't pop. I have changed the solenoid thinking that could be shorting out and it didn't fix the problem. I've tried backtracking the purple wire to eliminate and replace it directly to the dash but it crosses changes on its way there. the diagrams got a bit confusing. I've also been told the short is in the fuel pump but that doesn't make sense to me. Does anyone know which wire behind the dash would be the one for that part of the circuit or where I could look to bypass that wire?

I have zero experience with this particular machine but the advice to check the fuel pump is worth listening to if it has an electric lift pump. We had these exact symptoms on a Cat D6K2. The electric lift pump had shorted internally and blew the ignition fuse as soon as the key was turned to the "On" position.

Just had one this morning. Common failure on that Deere engine, The cold start advance sensor, top of pic 4, 2 wire plug. Is the culprit. Just unplug it for now, it won't do a thing till cold weather.

A bit confused. If you disconnect the purple wire, and it no longer pops the fuse, then why are you trying to back track the purple wire? That wire/circuit is not the problem if that's the case. And to clarify what ozrkag poster, absolutely the cold start sensor can cause this problem, but it looks like you have the black ground wire for the cold start sensor disconnected in pic #4. If that true, it could still be the cold start sensor if it's shorted out to frame, you need to disconnect the red wire connection for the cold start sensor at the fuel solenoid terminal where the purple wire connects. Even easier, simply disconnect that Weatherpac connector for the cold start sensor as ozarkag suggested and let us know what it does then.

As ozarkag suggested ,the cold start advance switch could be shorted . Could also be the cold start advance solenoid at the bottom of the injection pump is shorted.

I'll try unplugging the cold start advance sensor. The cold start advance solenoid is currently unplugged and removed as well. Thanks for the input.

That was the solution. Now to get it to run again after sitting for 3 years.

I have fuel going into the injection pump but nothing at the injectors. I took the return fuel hose off the end of the rail and a is cranking fuel will dribble out then stop for a second then dribble out again so on and so forth. I can slightly hear the fuel shutoff solenoid click when the ignition is turned on. Do you think the pump went bad from sitting?

RLG said: I have fuel going into the injection pump but nothing at the injectors. I took the return fuel hose off the end of the rail and a is cranking fuel will dribble out then stop for a second then dribble out again so on and so forth. I can slightly hear the fuel shutoff solenoid click when the ignition is turned on. Do you think the pump went bad from sitting? Click to expand... Post a pic of the tag on the injection pump. @thepumpguysc may be able to help you out.

Very well could have. I've had good luck cleaning out the old Stanadynes filling the filter with a 50/50 mix of ATF and Acetone and running/cranking until it gets into the IP, then let it sit for the weekend. Or can pop the lid off to see what the fuel inside looks and smells like, but be aware of where the FSS contacts the shut off cam for reassembly to avoid a runaway.

You may not need to fill it with anything, With the cover off, there is a metering valve the linkage turns. Those valves like to get stuck from sitting. I have had occasional good luck just reaching in there and working the valve back and forth to free it up. Like Marshall said, pay particular attention to where the fuel shutoff contacts the linkage so you can assemble it correctly. One caveat. If that pump has a lot of rust and scale in there, then I would recommend sending it out to @thepumpguysc for a little TLC. Also, that pump may have one screw on top that is a special tamper proof torx-like screw. Instead of 6 points, it has five points with a pin in the center.

This ^^^^! Another way to force your favorite cleaner into the DB2 without cranking is to use a cheap garden sprayer pump and make about 1/2 gallon of your favorite witches brew of cleaners (Brake cleaner, acetone, ATF, SeaFoam, B12, etc.). I tie it directly into the fuel line and pressurize the sprayer and let it sit for a few hours. Since the DB2 has a vane pickup pump, the cleaner should seep around the vanes and fill up the area you see in red in the above pic. Because the DB2 also has the little orifice (I forgot the actual name of that valve) that allows air bubbles from the red area into the yellow area, you'll be able to fill that area with cleaner also without having to remove the cover. Place your fuel return line in a clear bottle/bucket and you might be surprised what comes out. You may want to energize the fuel cutoff solenoid (by key on?) and tap the side with a small hammer to help the metering valve slide open. Doing this a few times "might" help before you have to pull the cover. If you're getting fuel to the vane pump and your fuel metering valve is free (you can only tell by removing the cover), then your high pressure plungers might be stuck. And that's a job for @thepumpguysc

Hi guys.. I’m just getting back to the fuel inj side of life.. Had cataract surgery in both eyes.. took 2 months off to heal up. RLG.. lemme know what u tried and where ur at now.. ill try to help.

thepumpguysc said: Hi guys.. I’m just getting back to the fuel inj side of life.. Had cataract surgery in both eyes.. took 2 months off to heal up. RLG.. lemme know what u tried and where ur at now.. ill try to help. Click to expand... I was able to pull the cover and move the metering valve by hand. I'm still not getting fuel to the injectors. What could I try next? I'm trying to not have to pull the pump. We've tried before and bent the puller so it's pretty stuck on there and would rather not have to pull it if I don't have to.

Did u “flick” the mv.?? In other words, did it return on its own.?? If u had to push it back, that’s no “bueno”..

Have u unplugged the harness from the csd on the pump or/and at the sensor at the coolant neck.??

thepumpguysc said: Did u “flick” the mv.?? In other words, did it return on its own.?? If u had to push it back, that’s no “bueno”.. Click to expand... Yes it would return on its own. I bought a new sensor and that fixed the fuse popping problem

But it’s still not pumping.? It’ll be easier to see if it’s pumping if u loosen the steel lines at the pump..instead of at the injectors.. Once u do get it pumping, tighten the lines AT THE PUMP & loosen the lines AT THE INJECTORS.. & bleed the air from there..

Thanks I'll try that.

thepumpguysc said: But it’s still not pumping.? It’ll be easier to see if it’s pumping if u loosen the steel lines at the pump..instead of at the injectors.. Once u do get it pumping, tighten the lines AT THE PUMP & loosen the lines AT THE INJECTORS.. & bleed the air from there.. Click to expand... I had some time Monday to mess with it. I pulled the cover off again and messed with the metering valve a bit. Everything seems to move fine and return like it should. Put it back together. Took the lines off at the pump and turned it over for a while. Probably a combined 2 min. The ports got damp but never flowed fuel. The whole time the return line was flowing fuel into a bucket i had set up. After that I had pulled the cover off the metering valve again mixed up a 50/50 of acetone and transmission fluid and filled up the cavity with that. Put the cover on and turned it over until I saw red come out of the return line and let it sit until today. Turned it over again today and still have nothing coming out of the fuel pump. Any ideas on what to try next?