322cl, I have no red lights screaming at me on monitor, just plugging through the monitor to look at historics and such. Monitor does indicate "low coolant" before firing but I verified it is not very low and will have to look further into that. I don't have books yet but this should be a 3126B engine. Active 69: 190-08 Logged Errors 69: 1162-03, 1163-03, 376-05, 190-10, 190-08, 588-09 24: 91-08 Logged Events 69: 17, 600, 43 24: 95, 5 I should note that I am not getting a tach readout on the display, just -. Because this is a digital link, I suspect there is a programming error on the ECM that the dealer may have screwed up. They were trying to diagnose something and reflashed it.
Realized most of this is in the electrical schematic.....duh This is leading me, however, to the only active code which is the 190 with FMIs of 8 and 10. I suspect either wiring between ECM and sensor, or the actual sensor is bad. Question now is what sensor is this code looking at? Where is it? Basic diagnostics seem to point to erratic behavior, not open so who knows just yet. I do know the engine does not seem to have one operating fault I can detect as of yet and all throttle controls seem to function fine. auto decel, manual settings, etc. I think the rest of the codes I will record and rinse and just see if anything pops back up.
As the Chinaman would say - sum ting wong........ MID 069 is the Tool Control System, which I assume you don't have. CID 0190 is the Engine Speed Sensor - usually preceded by MID 036 which is the engine control. Does the engine have one or two speed/timing sensors.? Does it have any at all..? FMI 08 is signal erratic, intermittent, or incorrect. FMI 10 is signal incorrect (a kind of specialized FMI 08 in other words) Neither FMI 08 or FMI 10 are listed your your machine. Only FMI 02 (loss of signal) or FMI 11 (mechanical failure). CID 190 FMI 08 would have no effect on engine operation so long as the engine is equipped with two speed timing sensors. The system simply uses the signal from the seconday speed/timing sensor. However if the secondary sensor quits so will the engine. However I wasn't aware that 3126B engine even had speed/timing sensors.
In my experience all the C series excavators have speed sensors. It's how the programed pump output works. Computer reads the throttle dial and compares that to the engine speed and then sets the pump output. You get that erratic signal all the time on older Cat machines. Sensor going bad and bad harness connectors are the usual issues. As I recall, you can read the signal in the monitor panel while the engine is running. The sensor for the coolant is in the plastic reservoir. The plastic turns hard and brittle over time and they crack and leak. I only check coolant level in the radiator. The hose to the tank is cheap and also turns brittle and allows air in. The radiator then doesn't pull coolant from the tank and then you run out of fluid and never get an alarm. I have a video on getting into the diagnostics and monitoring section of panel if you need, but I'm thinking you already know how to get in because you gave the codes in your original post.
John, sorry I should have made it clear I was referring to the speed/timing sensors mounted on the front end of the engine (usually two sensors mounted in a common housing that have to be replaced as a unit), not to an engine speed sensor screwed into the flywheel housing that gives a speed signal used for the pump control. Further investigation reveals that apparently the OP's 322C has both.
Nige, the 069 MID and these FMIs are present in the schematic you sent for the HEK serial. However, I note that the schematic appears to be wrong in that it shows a single speed sensor and I have verified I have a pair. John, the only indication of an issue is the active code and the lack of tach speed at the monitor. Why the ECM will not send it is beyond me, unless the engine is totally ignoring those sensors and running off the cam sensor? Ultimately, this will just be super fun! The sensors are below the HEUI pump and without taking the counter weight off, I will nearly be operating blind. I can just catch a glimpse. I do notice they are covered in oil. Where it is coming from, I don't know. What has me frustrated now is the schematic shows a typical 2 wire sensor, which would be a magnetic pickup. The picture above shows 3 pins, BUT a guy online shows that these are "magnetic" by picking something up. I guess I might have to verify if the 3rd pin is even used. In any case, these are right up my lane and I taught a class on magnetos and mag pickups. They are easy to troubleshoot and the wave pattern is just a simple AC analog signal. What can happen is the magnet will crack so the AC signal voltage drops below read threshold, or the winding opens, which is easy to spot. This is where I would LOVE to plug into that ECM! Why is it not sending anything to the monitor? If the engine needs that data to run, the data would be in the ECM and being used, even if running on a second sensor. I guess I can unplug them and see if it starts......
With conflicting information available in the system and what you can physically see on the machine, here's what I think....... The MID 069 for the Tool Control System could actually be better referred to as the "Pump Control System". So the 2-wire magnetic speed sensor mounted on the engine flywheel housing is the one that gives an engine speed signal to that system in order to control the implement pump output. That's the one shown in the RH illustration above screwed into the housing and adjustable using a locknut. It's referred to as 189-5746 Eng Spd Pickup and is located in Grid D-10/D-11 of the schematic just above the starter motor. it is CID 0190 in the electronic diagnostics. The sensor in the LH photo above is the non-adjustable speed/timing sensor and is located on the lower front LH corner of the engine. The primary speed/timing sensor appears on the Code list as CID 0320, the Secondary Speed/Timing Sensor appears as CID 0342. Why the speed/timing sensors do not appear on the electrical schematic I have no idea. I'm going to dig for a schematic of another machine that uses the same engine to see if it appears there.
AH!!! I am looking at the wrong sensor! Look at B11 in schematic to show the double cam/speed sensor! I am looking for another sensor! My luck is it will be on the bottom of the engine....lol The on you reference in the D10 area is the one I am looking for. It is starting to make sense that the double sensor is probably functioning perfectly and the 1895746 is what I am looking for.
That the one ........... hid that well didn't they..? Here's a Troubleshooting Procedure from a D-series machine. You can use this but make sure to use the wire numbers from the schematic applicable to your machine.
BTW your magnetic speed pickup should be in plain sight pretty much right on top of the flywheel housing.
I think we have our critter! Thanks! I was able to find it. I was looking at the wrong end! It is on top of the PTO bell housing. The sensor tests at 165ohms and per the test procedure, that should be 5ohms. I find that value to be quite low for a pickup, but........ So it looks like the sensor is toast. Crap, I misread the procedure. Who wrote that???? lol Just tell me what the coil resistance should be! Let me dig further. I was reading where they want me to verify the harness wiring continuity.
Reistance should be 142 ohms @ 25 DegC ambient. Do the tests in order that the procedure lists them. You check the wiring first then the sensor. The fact the sensor is in the ball park resistance-wise suggests a wiring issue anyway.
Or programming, which I still suspect because the dealer reflashed that controller trying to fix a simple wiring issue in the past. They were going to throw a controller AND a wire harness at a simple wiring issue! They flashed a new controller and did not fix the problem so they reflashed this one and reinstalled. I will test wiring though!
It might also be an idea to remove the sensor and inspect the tip for metal particles. When you reinstall it you also have the chance to set the sensor adjustment. Make sure there is a flywheel tooth directly under the hole. Screw the sensor in until it touches the tooth, then back out about 4/5 of a turn and tighten the locknut. Everything you eliminate points you to what will be the final root cause of the problem.
We got er! I think this was another "dealer special"..... That sensor looks brand new and I think this is another "it wasn't the sensor so you need a new controller"...... It was the female barrel pins in the connector to the sensor. The way I do this is since I know there is a known resistance, I should have had that value at the J2 connector. I had nothing. Then I went through "the official procedure" which showed perfect continuity BECAUSE I jammed a jumper into that plug. That took me right to that connector, in which I unpin the connector and rework the barrels. She now reading perfect RPM..... Next question.......And one I won't be able to "electrical troubleshoot" my way out of. I should have looked much closer at this machine. It needs rails. I am not sure I would trust putting it on a remote job like this. Previous owner already had a couple links break but said that was due to the bushing seizing to the pin. I may have to make a decision if I keep this around or not.
Glad you found the problem. FWIW your undercarriage is probably the subject for a new thread......
Did I mention that speed sensor earlier?
Yes John! You and Nige were great resources on this! However, I am questioning the programmed use for this sensor in this application? This machine already has two other speed sensors. Contrary to some info online, I do not think the "pair" are intended to for redundancy, but rather they are tuned for different ranges or offer a cross check since a poorly timed injection event can burn down an engine. however, on the 3rd tach sensor, it would almost seem that the hole was there, Cat plugged it, and just sent that data to the monitor. BUT, that data does first go to the engine/pump controller so......
It is my experience that the speed sensor on the bell housing for Cat C model excavators runs the tachometer function in the monitor panel. That why I brought it up to begin with. The pump controller and the engine controller work together to handle the performance of the "machine." The sensors on the engine are there for the operation of the engine. If they don't work, then the engine doesn't run. It's as simple as that.
If I can add that the pair of sensors on the front of the engine are more for fuel injection timing, despite their name of "speed/timing sensors". As John says if they go bad the engine doesn't run. They have nothing whatsoever to do with the performance of the engine/implement pump system.
Well....John has just said he believes the tach sensor just provides data to the monitor. Obviously the engine/pump controller would need to have tach data to compare desired vs actual engine speed to optimize pump stroke. Though I don't have much time on the machine yet, I can say that it did not seem like the machine was in any sort of limp mode or have any performance loss with the tach sensor not working. The engine seemed to respond as expected, and auto idle worked normally. Not seeking an argument, just laying out what I know for now as I would sure like to know! It could be the reason the previous owner said it used a lot of fuel! It could also have caused excessive hydro oil heat if pumps over over stroked for demand.
It's good that you are poking around and learning about the machine. I just didn't want to see you put in a lot of time and possibly waste money possibly changing a part somewhere that didn't need to be changed. The speed sensor on the flywheel is the critical part that basically tells both the engine and pump controllers what needs to be done to keep the machine working at its peak performance for the setting of the throttle dial. You are on the right track when looking into fuel usage. I've been on the road all day so I'm not thinking real straight right now. When you get the time, try running a cycle time on the boom up function to check the performance. It should be quicker that 4 seconds.
I ran a quick test. Warmed the engine up to "reasonable" and cycled hydros a bit. I did not really "time" the boom up but I can assure you it will run from down as much as I can with bucket/stick curled to me, all the way up in less than 4sec. I would say closer to 3sec. What I am trying to get my head around is how the machine was functioning without this speed sensor active? I do know it felt decent and did not seem to bog the engine much, but maybe that was part of the limp. It would not get down and dirty? I really want to know the default mode if the speed sensor is not active? I will say I noticed the track motors did not seem all that powerful to 'me'.... Was not bogging the engine much, just would not pull, BUT I was not at full idle for that little test either. I usually suspect the swivel on something like that, but...... And why in the world was the monitor not screaming at me about this sensor????? It seems critical for proper machine function, yet no red lights, and I only know of it by going into the service modes and checking codes! Cat, why you do this?
A service manual or subscription to Cat's SIS might answer all your questions. I believe the system was designed by someone in Japan and they don't talk about the how or why they think the way they do. All we can do is react to what we see and read.
I've already been down that particular rabbit hole with this gentleman John ....... For anyone who's never had the chance to get into SIS the sheer breadth of information it can come up with is quite frankly staggering. I must've started using the online version 20 years ago and I'm still finding stuff that I didn't know existed.
A grand PER YEAR is hard to justify SIS for a couple CATS! I am searching for manuals at the moment. I realize SIS is a sweet deal but apparently the dealer won't let me take a test drive to find out how sweet....lol
I think that is what is wrong with the industry and Caterpillar in particular. It was my understanding that you got access when you signed up for a parts account in the early days of the program. The dealer where I worked cut off all access to anyone who wasn't employed there years ago. Just the same, you will have to be a really exceptional person to try to understand how the system works and what is going wrong and how to fix it without having access to that info. Looking at it from the other side though, $1,000 a year is cheap compared to a dealer service person. Minimum cost for a field call now around here is around $1,200 without even fixing something.
John, I have to agree! I could peck out a novel but IMO, the service industry is not what it was 30-40yrs ago. "techs" are cranked through a program, earn their special badge, and have no real understanding of what they are working on! They go through a checklist and swap parts. I call them "parts changers". I would expect for the price of service today, they should show up knowing what they are working on VERY WELL, not sit in a truck reading books. I have, however, known many GOOD techs and those guys are typically covered up with work! I work a LOT with automation and electronics and I find that techs out there don't even understand how a resistor or diode works. This is not unique to Cat or even construction equipment! When a tech is not competent to troubleshoot a problem, the customer should not be on the hook for his "on the job training" and all the replacement parts thrown at it.
Woulda, coulda, shoulda. At this point in time from our particular point of power, we can't change what is. We can only react to what is and do the best we can with what we got.
There also seems to be some confusion here about the terminology. Cat calls the engine controller the ECM. However the pump controller on the earlier excavators, instead of being called the pump ECM is officially called the "engine/pump controller" or EPC. The two sensors on the engine front housing are called speed/timing sensors. They only interact with the ECM and are only involved in making the engine run. One of the EPCs main jobs is to control powershift pressure and it takes its engine RPM signal from the bellhousing sensor.