I'm having trouble with the starter on my Komatsu PC45, hoping for some help. It has been slow-starting when cold, but would always start immediately once it was warm. The engine sounds and runs great once it's started, so I first suspected the battery was getting old. After installing a brand new battery, it still turned-over much slower than I would expect from a properly working engine. Getting the same result with the new battery, I think it's safe to rule-out the battery, alternator, charging system and voltage regulator. That left me with possible causes: -Bad starter motor (brushes, wiring, solenoid, etc.) -Resistance in hydraulic circuits or pump, bogging down the starter -Exhaust valve not opening all the way I was able to rotate the engine by hand by turning the main pulley, which seems to rule out any internal resistance in the engine or hydraulic pump. Unless I missed something, that points pretty clearly to the starter. After sitting for a day, I tried to start it again and hear only the click of the starter solenoid, but no cranking. Charging the battery doesn't help, neither does banging on the starter to free up a stuck solenoid or bendix. Maybe this points to the way the starter is failing - the brushes or their wires are worn. When I stopped the motor, it seems I may have landed on a dead spot where the worn brushes don't make good contact. In any case, the way to find out is to remove the starter. That's where my real problem starts. The lower mounting bolt is easy to remove, but the upper bolt is just beyond reach. Using a flex joint, I can _almost_ get the 17mm socket onto the upper bolt, but the solenoid interferes with the socket. I'm laying on my back looking up. Can someone please tell me if there is a special trick? I already removed the hood door and intake filter to see if I can access from above. But to get access, i'll have to remove the muffler, exhaust pipe, and exhaust headers, possibly more. This seems like a lot of work to remove a starter! I'm very reluctant to take this approach, because a lot of the exhaust manifold studs are corroded badly. I would really hate to break those studs and end up pulling the engine just to get the broken studs removed. I don't have a service manual, but would buy one if it was available. This is a gray market machine. Any hints on how to remove the starter? The engine is a 4D84-2B Komatsu Diesel.
Napa had the flex head box end gear wrench sets on sale a week ago. Might want to check them out. If you can get a socket on you should be able to get a gear head in there. They are great for situations like this.
When you say slow starting when cold, how cold is it? If the temperature is real cold the oil could be causing problems. In my truck the difference between 15w40 and 0w40 when cold is day and night difference.
Haven't worked on a 4D84, worked on the 4D95 engines, don't know how similar they are. Do you have a removable panel under the engine? Many times you can remove this panel and access the starter from underneath.
As I recall the starter is on the cab side of the engine. There is a panel that can be removed of that side for access but it is a bugger. The sheet metal over the swing motor has to all be removed. That engine number doesn't ring any bells with me. Is it a three cylinder or four cylinder? The three cylinder I believe is a Kubota engine. Good Luck!
Thanks for the responses guys! The cold weather was around 30F when I last got it to start. It seemed no slower in 20F weather. If it really is the oil viscosity, then the easy starting when warm would be explained. Currently, I have the underbelly access plate off, so I have good access to the bottom of the motor while laying on my back. I agree that flex wrenches are great, however, the access is so tight from below that I can't get any kind of wrench on the bolt. If I really contort my hand and fingers, I can just manage to touch the head of the bolt with one finger. With just one finger, I can't really push a socket onto the head of the bolt. Yes, the starter is on the cab side of the engine. Getting access from another side sounds appealing, although I'd like to avoid removing the cab if possible. The 4D84 is an inline 4. While doing research on the web, I've uncovered a number of other PC45 owners with the same engine, usually by reading their posts on forums. The engine says Komatsu on the serial number nameplate. Since I have the enclosed cab, will I likely need to remove the entire cab? I don't have a warm, dry shop to do the work, and I just sold my forklift. =(
I thought there were some sheet metal pieces in the middle of the machine behind the swing motor that could be removed to access the starter. I could be wrong though
I took a closer look at the machine tonight to see if there are convenient access panels that can be removed. From below, I already had all the covers removed. The only steel plate left is about 1" thick, so it's got to be part of the frame. From the left side, there is one small triangular vent panel that can be removed, which allows great access to the spools and hydraulic connections. It looks like it might be barely possible to snake my arm in between the hydraulic hoses to reach the starter, although it is pretty far to reach. The right side panel could also be removed, but to get access to the starter from that side, I'd be removing the radiators and alternator and a bulkhead. I've also concluded that removing the exhaust header and muffler wouldn't be the right way. If I unbolt the muffler, there would be no way to remove it without removing the cab.I can't imagine that's the intended method to remove and install a starter. They sure did shoehorn the engine in there! Perhaps the intended method is to access from below with a special tool, or possibly a flex socket that isn't as long. I've made a few more attempts and can get the socket partially seated, but end up rounding off the bolt corners instead of breaking it free. Any other ideas?
It sounds like you got all the bases covered. Without looking at one now I don't think I would have any other thoughts. May go a pawn shop and buy some cheap sockets and extensions and modify them as needed. Let us know how you finally get it done.
Yeah, I think I'm satisfied that I'm not missing any easy access. I shopped around locally today without finding a short enough flex socket. That's why I have a bandsaw and a welder, I suppose. It won't be the first time I've had to build a tool.
Do you know the correct size? I have a few flex sockets that are real shallow universal style. Where the universal is part of the socket itself. Can you get a crowsfoot on it?I would venture it is metric.
The easy bolt is 17mm and I was assuming the other bolt is the same size. I don't think a crowsfoot will fit, but I might go get one, on the off chance it will work. I have a set of very shallow universal sockets, but they are all in inches. I'll probably go to sears tomorrow looking for a metric set, since the sockets that I do have are by Craftsman. I'll let you know how it goes tomorrow.
Problem Bolt Alright, I've tried a number of things without success. Neither the metric flex socket or offset box wrenches did the trick. I did, however turn up some diagrams of the cab and access panels, which are mildly promising. There's a panel behind the cab (#15 in the diagram) which would seem to give me access to the starter! And there is a corresponding panel on the cab (behind the seat) which would line up. I'll still have to disassemble the seat and right controls to get to it, but it's better than removing the entire cab! Anyway, thought you guys deserved an update.
Safety Relay? Another possibility... When I turn the ignition, I hear only the click of a solenoid and assumed this was the starter solenoid. Is it possible there is another solenoid, perhaps a safety relay? Or can I rule out the safety solenoid because the control console lights up and is getting power?
The click you hear is likely the fuel shutoff solenoid. From the pics it almost looks like you have a hot spot on the starter where the solenoid is attached. They never make it easy to work on starters for some reason.
It's hard to see from the picture, but the starter solenoid is behind the main body of the starter. I have a slow leak from the oil pressure sender; the dark spot is where oil has dripped off the starter, since it's the lowest point on the starter. I took these photos laying on my back under the machine, looking up. I'll have an assistant help me check which relay is in fact making the click. Thanks for the idea about the fuel shutoff!
Starter Here's a view of the starter solenoid that shows how it hangs off the starter motor. It creates a narrow area against the starter flange. It's thorough this narrow opening I have to get a socket.
There is a safety relay on the starter that prevents it from engaging when the engine is running. It is powered from an extra wire on the alternator. When you turn the key the battery relay closes which is probably what you are hearing. Since the engine is not running, the extra wire on the alternator has no voltage and the safety relay is closed. It allows amperage to flow to the starter solenoid. When the engine starts and voltage builds up in the alternator the wire becomes hot which energizes a coil in the safety relay causing the switch to open thus preventing the starter from being engaged. When the alternator is going bad the diode that feeds the extra wire usually leaks through preventing the starter from turning. It's easy to test. Turn on the key and check for voltage at the wire. It looks to me like you have the panel situation figured out. All the small Komatu excavators I have worked on did not have a cab. Thanks for the update on your project.
Two words!!! Seat switch.
My pc40-7 did the same thing a few years ago. that click sound still haunts me, got the starter fixed, all good. you can give it a tap with a hammer and it will go to, did that on the job to get it done. there was the same access panel's that you have from the cab to the engine. my digger had around 4500hrs on it when it started doing the clickthing. good luck with the fix.
Seat Switch After all that trouble, it turns out the problem was the seat switch. My lawnmower has one, but for some reason I assumed larger equipment had no such deadman switch. I did learn a lot about my machine in the process, and I will eventually be replacing or rebuilding the starter because it still cranks slow. But for right now, I'm really happy to have a running machine again!
You have to love all the effort they put into safety switch systems these days! Glad you figured it out and got it running. Good prep for when you do have to pull the starter. Thanks for letting us know the final fix. It will help someone else down the road.
Now that is a new one on me. I know all the relays and diodes are under the seat but have never seen a switch on the seat that prevents starting. Thanks for the update.
My Gehl skidsteer is that way. His OP did not make me think about it. Gehl you have to sit down and pull the bar down. At least you can get out with it running and it puts the hydralock on the minute you raise the bar.
Red Handles There's a similar system on my PC45 - red handles that you pull back before you exit the machine. It puts the engine at idle and disables the controls. The levers are designed so that it's hard to exit the machine if you don't pull them back. It's a good system, because there have been quite a few times I hooked the control levers under my raincoat as I got in or out of the machine.
Yep. I have bumped the levers on mine before and you hear it strain but everything stays still so it is a good idea. It just makes troubleshooting a whole lot tougher at times.
Not the seat switch. With the help of my friend, who is a diesel mechanic, we first got the excavator to start by pushing a knee into the center of the seat. He had noticed the wiring harness that terminated under the seat. When the starter began working again, we concluded that was the problem - the switch was intermittent. I did an experiment today to verify that it was, in fact, the seat switch causing the problem - I tried to start the excavator without sitting in the seat. To my surprise, it started! So either there is no seat switch, or else it is now stuck in the "on" position. It seems more likely that there is simply some intermittent connection in that wire harness. Perhaps I bumped the harness while I was removing the cab access panel (to get to the starter), which restored the connection, for now. Eventually, I'll go tidy up all the wiring and fix any possible loose connections. The radio doesn't currently work, and the previous owner patched-in a fan, so there are a few obvious things to clean up. Anyway, I didn't want to leave the thread as-is with people thinking it was the seat switch, lest I send the next guy with this problem on a goose chase.
That makes a little more sense to me. Under the seat there are some relays and diodes. I've had problems with wiring under there before when a battery disconnect burned up some wiring. If just moving around on the seat caused the thing to start working, I would recommend you pulling some sheet metal and finding out just which set of wires is giving you the problem. Either a wire is not making contact or it is shorting out. Good Luck!
Agreed, it's next on the list. In trying to access the electronics under the seat, I stripped one of the phillips-head screws on the access panel. I should have used PB Blaster first. It's a job for next weekend I think. It's supposed to rain all week. =) Thanks to everyone for the advice and help in diagnosing this!
I have a PC40-7 and do not have to be in the seat to start it. Just fixed the 210S after having starter problems. The 'click' and nothing. Same thing happened on one of the farm tractors ...loosen the wiring at the starter and solenoid, clean it up and tighten it all up good. See if that doesn't help the problem ...usually does when the thing was starting OK then not at all. Slow crank indicates a bad starter motor, the airplane did this last summer. Just amazing what a new lightweight starter did for the old girl.
My PC-45 has fuel filter issues. It starts, idles okay for a minute or 2, then gurggles and shuts off. I'm wondering if anyone know where to buy filters online? The Google is more and more useless for finding sites, vendors.
Well, at least you have access panels, my tak doesn't, and I had to remove most of the rear end of the machine to get to it. http://www.youtube.com/watch?v=iDT008G-V-8 I ended up using open ended metric wrenches as sockets were to tight for the castings on the Yanmar engine. I too replaced a perfectly good battery, $102.00 later, and it was no better. (I also tried the tapping thing.) The starter listed for almost $600.00, so I opted to get it rebuilt at a local shop. Starts fine now, and it cost under $100.00 to get it done.
My spider also has a started mounted in the most retarded spot. Even with the removable firewall panel removed you need a special tool to take it remove the one bolt. Fortunately the machine comes with it! It's really nothing more than a bent Stahlwille box end wrench.
Are you sure its the filter? My Tak was pulling that crap on me, and it turned out to be the electric fuel pump on its way out.
Do engineers design these things, or just evil little bridge trolls....?