I took in a trade for a debt a Hitachi ZX55USR-5A grey market machine with a lot of wiring issues and the read out screen is nearly impossible to read. My mechanic replaced a lot of zombie frankenstein wiring some Yahoo tried to fix and since we cannot find where to buy a new monitor screen decided best to go old school and just put in a oil pressure, coolant temp and Amp meter gauges and bypass the computer screen. Has anyone done something like this? Anyone know if you could contact Hitachi in Japan and see if they would sell the monitor screen itself and/or computer? The electrical system has all kinds of broken wires, wires piggybacking on other circuits and we spent days already chasing down each individual circuit going through a new fuse box since the old one was melted./rusted out. The machine is not that old, built in 2020 but I just want to get it running proper and sell it. It has a 4 cylinder Yanmar in it that runs good. Thank, Ray
Remove the monitor and check for a part # on the backside. It may start with YD or FYD.
Diesel Dave: Thanks for the tip. I will do that tomorrow when I get the Model and serial number off the Yanmar engine. This poor machine was so poorly maintained , 1/2 of the grease fittings were missing with dirt packed into the holes or broken off. Took me hours to hammer out the 4 bucket pins, only 1 had grease inside, the others bone dry.
The number on the back of the monitor is: YD00009441 followed by another number of 347-2306-000 and a serial number of 1503000100. I went to the local tractor dealer today to get new grease fittings and asked what these type of monitors cost and he said he just replaced one on another bigger trackhoe and the cost was a whopping $4500!!! So not going this route since I just want to get this thing running proper and sell it at the auction. So got to find out how to just get a oil pressure, coolant temp and amp meter gauge set installed to work with this Yanmar diesel. The engine model is 4TNV88-BPHBB and engine No. P3920.. It just has wires going to the Oil pressure sensor and same with the Coolant
A lot of times it’s easier, if you are going electronic, if not mechanical, to get the oil and coolant sensors in a matched set, as the OHMS can be different and if you don’t know the factory OHMS setting, unless you know how to measure the resistance. They aren’t very expensive and you can buy the sets off of Amazon for usually under 20 bucks for each set. Same with the AMP meter, I just bought a decent digital one off of Amazon that has different backlighting for under 10 bucks.
Thanks for the reply. I was checking out these gauges off Amazon and see you can get all 3 for around $30 and guess they are what is considered mechanical with the circular dial and needles. When you say an electronic type, there is just a number showing on a screen like currently on the malfunctioning monitor?
No, mechanical is actually the direct reading of what function you are looking for. Example, a mechanical oil pressure gauge, requires a line, don’t use the friggin cheap nylon or plastic hose, stainless lines but you are selling so, anyway. It uses actual pressure to gauge, temperature uses a bulb type that actually reads the actual temp. The other style uses a resistance type bulb or pressure transducer and that corresponds to the resistance readings of the gauge. Therefore, you need to match gauge to meter, has to be the same. Therefore are adjustable fuel gauges that are quite inexpensive and I have actually had good luck with them, for matching the sender resistance. For what you are doing, I recommend buy the cheap three ganger and just make sure wires are all long enough, they usually are way too long anyway.
I got my replacement fuel shut off solenoid for my Yanmar diesel in the Hitachi trackhoe. It was a cheap Chinese one but turned out to be the exact one that was burned out right down to exact matching model and part numbers stamped on it. My mechanic installed it today but he was concerned on how hot is was while we were adjusting the throttle idler adjustment. Some of the reviews on line mentioned that these solenoids do not last long and we were concerned about the heat build up as being the cause.. When we turn on the ignition, this activates the plunger and the solenoid apparently just stays on constantly while the engine is running and when ignition turned off it releases and shaft moves to cut the fuel. Anyone know if these solenoids are supposed to be drawing power constantly while running which is what is causing the heat build up? This solenoid has three wires going to it, one is power the other ground but we were not sure what the red wire was for. We tested it using the red wire for power but nothing happened so he thought it must be a wire going to a gauge or another sort of shut off safety device.. Anyone have any suggestions here? Thanks
Typically when you have 3 wires on a solenoid like that you will have a pull in and a hold in winding with a common ground. The pull in winding consumes a lot of amperage as it needs to pull in the plunger. Once it's pulled in the pull in coil gets deactivated and the smaller hold in coil can keep the plunger in just fine while consuming a lot less amperage. I'd wager a guess that someone probably spliced the 2 windings together at some point and all the power it's consuming is making the heat.
If you run it like that for any length of time, it will burn that starting solenoid out. Generally it’s a 30 amp fuse for pull in and a 5 to 10 amp fuse for the hold coil.
White wire is the pull in coil, red wire is the hold coil. I believe from new the pull in coil was controlled by a relay controlled by a “timer”. Relay could be stuck closed, also you say your electrical/wiring was a zombie disaster. Suggest to wire a pull in coil relay into the start circuit so it is only powered when cranking.
The threads for the oil sender might be British. Found that on my Tak that has a Yanmar.
Had to make a detour on my electrical problems and concentrate on the undercarriage rollers. They were all pretty much shot only 2 still alive so bought a full set of 8 which turned out to be JD 50 D rollers which were just a few mm's larger in diameter than the old PC 40 ones taken off...They were cheap Chinese knockoffs but got them for a little over $100 a piece but then there was a $160 Tariff add on for all 8 and yes the consumer , me, ended up paying the tariff, not China or the importer. So now concentrating on the alternator which I had rebuilt. It is a Denso # 101211-1170/12356 and it has a plug with 3 small wires next to the big primary red wire that goes to the battery. Since all the wiring on this rig is screwed up with splices not matching the color codes I called the shop and they told me the 3 small wires are as follows numbering down from the big Red wire. Prong #1 is for Lite or Lamp which supposedly would go to the monitor when key is turned on and go off once alternator is supplying juice. The 2nd prong, in the middle is the "exciter" which energizes the alternator when the ignition switch is turned to on. and the 3rd prong is supposed to supply 7 volts going somewhere. Now we turned on the key and the wire going to the center had no juice so we hotwired a line to the battery, started the engine and the alternator was kicking out around 14 volts and the 3rd line was showing 7 volts like the shop said it should. Checking out the AI posts, they claim that 7 volts is supposed to go to either a tachometer or a hour meter. Another post claims the Lamp lead is supposed to go to the computer which then goes to the dash and also regulates the voltage regarding battery power levels which I am guessing keeps the battery fully charged but does not "cook" it. My dilemma is not knowing if this computer is even working or if it got fried when the fuse box melted and the bozo rewiring someone did after. The monitor liquid crystals are all jumbled up so no way to read it. The only good thing it shows is the red oil pressure lite when key turned on and once engine fires up, the lite goes out. My main worry is if the other 2 wires (#1 & 3) are hooked up wrong and/or computer dead that the alternator will keep supplying 14 volts to the battery and not know when to shut off or does the built in regulator some how manage this through the big supply wire? Instead of buying another fuel shutoff solenoid and cooking it again, I just built a manual shutoff cable using a NAPA choke cable and it seems to work just fine. Any advice on the alternator would be appreciated. Thanks, Ray
Typically, machinery alternators are controlled by the internal regulator. Easy test is to run the engine with a multi meter and check the voltage after 10/15 minutes. It it ramps up over 15volts you probably have an computer controlled “smart alternator” system. This is unlikely as it is more of an emission system.
It sounds like your customer got a good deal. Got rid of a flogged out, unsellable, money pit and got what ever you did for them for free.
Is this the display? I can't believe your dealer quoted 4500USD, it's 300USD at most.
That looks like the monitor and i have the numbers off of it at the beginning of this string. The tractor dealer that had that sky high price was talking about a very large CAT, not sure how much labor was involved in what he was talking about.. This scam artist who dumped this machine on me got it out of Pennsylvania probably from one of his network of shady dealers nationwide. He was my business partner until he embezzled all my money out of the business and supposedly used it to buy an island off of Panama. He has/is being sued by people from New Jersey, Costa Rica ,California and recently ripped off some folks out of $40 K down where my "Island" is supposed to be. I told him unless he starts paying the money back I will go to the IRS and just write off the loss but he never filled out any profit and loss statements but he sent me this POS machine to try to stall me, claiming it was worth first around $40 K, then he said $30, then $19. I can tell it was rolled over since two of the bottom rollers were actually tore out of undercarriage and a sloppy weld job fix, arm has a bend in it and big cylinder severely gouged, will need to be re-chromed or replaced. I spent over $2500, around 100 hours, just to get it presentable to sell and if lucky, will sell for $15. which is about 5% of what he ripped me out of.
The 3rd prong “P” in the alternator connects to the starter safety relay so the starter motor won’t engage when the engine is running. . Check your messages.
Thanks, we got the page on the schematics that I had printed out.It is different from what the Alternator tech who rebuilt the thing. He told me the prong closest to the Battery big wire was the Lamp, center is ignition and P is furthest away. The schematics show the P being closest to the Big Battery line. All I can say is the mechanic tested the P prong when we got the engine running (the prong furthest from the Battery wire) and he said he saw 7 volts which is what the tech told me it is supposed to show. Since the schematic and the verbal advice has the 1st and 3rd prongs reversed I am nervous about that prong that is kicking out the 7 volts. If I send that to the wrong place could further damage the system. Normally it is easy to just follow the old wires by color code but this previous "mechanic"had changed wire colors at the connection points so we will just have to dig further into the wiring harness till we find the original wiring. To further complicate matters, when they rebuilt the Alternator they put in a new plug but the colors of the wires hanging out of it were totally different from the old plug. Lucky I kept the old plug and will follow the old wiring colors down into the harness till I find the match up. I would really like to get that safety circuit where the starter can not activate while engine is running hooked up right
Screenshot below is the face view of the original harness connector to the alternator. . Screenshot below of plug on the alternator