Cat 289c

[Drago663]

I checked the TPS, it is the newer model number.

After adjusting the governor linkage to favor more throttle, the slowdown problem is allot allot better! “if” it’s still there it is barely noticeable now! Only small down side is the slow idle is around 1050 instead of 950 before. Hence why it really should be simply calibrated by the cat ET…

For the most part I believe that proves the tps simply needs be calibrated.

Now that I understand the underspeed system it all makes sense, thank you Chrisso for explaining it!
Even the certified Cat technician doesn’t understand why the tps calibration would have anything to do with the machine slowing down… (even after I pointed him towards the Cat document mentioning the slowdown problem that Nige posted.)

 

[Drago663]

Glad this forum has helped Gary! Im usually lurking on the sidelines learning in these forums myself. They are invaluable when facing questions no one asked before.

This is the service pdf I came across that mentions the underspeed system on page 60.
I will try to upload it incase it can help anyone else with similar problem.

Funny enough Nige, after reading this service manual There is a section on page 30, describing The optional Advanced Machine Information and Control System (AMICS) that you had asked if my machine had a long time ago. I did not realize until I came across it in this manual that I do actually have that! Oops…
I think using it I can actually view the TPS reading. But still cannot calibrated unfortunately.

On a side note does anyone know where I can get a Cat ET? I tried searching for one and came across plenty but its ruff to sift through all the knockoff option out there.

 

[Nige]

Even the certified Cat technician doesn’t understand why the tps calibration would have anything to do with the machine slowing down… (even after I pointed him towards the Cat document mentioning the slowdown problem that Nige posted.)

Just 'cos someone has a Cat badge on their shirt doesn't necessarily make them any smarter than you.......
I'm a mechanical engineer by profession and sometimes even I struggle to understand stuff.

 

[Chrisso]

Just 'cos someone has a Cat badge on their shirt doesn't necessarily make them any smarter than you.......
I'm a mechanical engineer by profession and sometimes even I struggle to understand stuff.

And the amount of machines Cat produce, it's just impossible to fully understand all of them. But the trick is to do research before you go to a job. If he had done that, he would have shown up to the job with a new TPS at a minimum... as Nige (or someone) said in a previous post, the title of the service letter couldn't describe this problem any better "machine slows to a stop"!

On a side note does anyone know where I can get a Cat ET? I tried searching for one and came across plenty but its ruff to sift through all the knockoff option out there.

Only legitimate way is to go through your dealer and ask to speak to your Product Support Representative. You'll pay a yearly subscription usually.

 

[Chrisso]

Thanks for sharing that training manual also. Has some really good info.

 

[Drago663]

Fixed!!!
Thank you to everyone who helped get to the bottom of this!!

After acquiring a CatET I was able to go in and calibrate the TPS. And it did in fact fix the slowdown problem!

For reference to anyone who has similar problem, just a quick re-cap in hope this might help in the future.

This is a Cat documented problem and I have attached the official Cat service document that outlines the problem and what Cat suggestion is to go about fixing the problem. As well as a service document that describes “Engine under speed function” on page 60. because the Cat service document by its self is vague.

In the service procedure document, Cat mentions making sure the TPS sensor is the newest part number, and if not, upgrading, then re-calibrating.

I found my machine to already have the newest TPS part number which is 266-1467

After spending countless of hours researching and checking for problems, I finally (with much help from this forum), tightened the throttle cable so it was intentionally pulling the throttle too much, and the slowdown issues went away. (Doing this brings the rpm high enough compared to the TPS, to prevent the ECM from kicking in the underspeed) Only problem then was the machine now idled too high. But this confirmed the problem was in fact the “under speed” system kicking in.

After confirming the TPS sensor was the new model, the only thing left was to adjust the throttle cable back to proper adjustment, and re-calibrate the TPS. Using a CatET.

Attached are the two pdf documents that helped me get to the bottom of this.
As I mentioned above, this is a documented problem for the following machines. Hope this helps…


279C (S/N: MBT1-UP) 279C2 (S/N: KWB1-UP) 289C (S/N: JMP1-UP) 289C2 (S/N: RTD1-UP) 299C (S/N: JSP1-UP) Multi Terrain Loader 287C (S/N: MAS1-UP) 277C (S/N: JWF1-UP) 277C2 (S/N: MET1-UP) 287C2 (S/N: SSB1-UP) 297C (S/N: GCP1-UP) Skid Steer Loader 246C (S/N: JAY1-UP) 256C (S/N: DWS1-UP) 262C (S/N: MST1-UP) 262C2 (S/N: TMW1-UP) 272C (S/N: RED1-UP)

 

[Gary Layton]

Awesome follow up. And awesome that you got it fixed. It's encouraging to know that things actually can be fixed even if it does seem to take a little bit of voodoo.

 

[Quki22]

I have been following this thread and glad to hear you got your problem resolved, nice work. I took my 2008 cat 277c JWF01714 to the local cat dealer for the same issue. I provided them the service bulletin regarding this known TPS issue and for what ever reason they went on a hydraulic problem hunt. I asked them to replace the TPS and calibrate it. They changed the TPS and tell me it still won’t calibrate. So needless to say I’m out a significant amount of $$$ and am no better off than when I dropped it off. Anyone have any suggestions as to where I should go from here?

 

[Tyler d4c]

I have been following this thread and glad to hear you got your problem resolved, nice work. I took my 2008 cat 277c JWF01714 to the local cat dealer for the same issue. I provided them the service bulletin regarding this known TPS issue and for what ever reason they went on a hydraulic problem hunt. I asked them to replace the TPS and calibrate it. They changed the TPS and tell me it still won’t calibrate. So needless to say I’m out a significant amount of $$$ and am no better off than when I dropped it off. Anyone have any suggestions as to when I should go from here?

There's no such think as it won't then give up there's a reason it would they need to find it or give you your shillings back

 

[Quki22]

They told me they would continue to troubleshoot but it gets expensive at $150 an hour. In hind sight should have purchased CatET and components and did it myself. May still do that and come out ahead. Just don’t know where to go if the new part won’t calibrate

 

[Drago663]

Unfortunately, thats similar to what happened to me, I had Cat tech come out to calibrate the tps, he giggled when I told him I thought it was the TPS and showed him the service bulletin, tested the electronics and said everything is perfect with the electric system so did not calibrate, instead decided it must be hydraulic, took a sample to analyze, two weeks later got the results back and found everything was perfect with the hydraulics. So I was back to square one, at which point he suggested I have him come back out to calibrate and/or trouble shoot more. But it’s really big $$$$ to have them come back out and I had already spent too much not getting anywhere, thats when I decided to try to get a CatET and calibrate myself.

There is no guarantee that your problem is the tps, but I would not rule it out till you get the tps successfully calibrated!

I seem to remember reading a thread on here where someone was unable to get their machine to calibrate the tps. I can try to see if I can find it, but I think it came down to making sure the throttle cable’s where properly adjusted, and possibly even had to get a new cable. In said thread someone even uploaded the directions of how to do so.

What I will say since I just calibrated mine the other day, is I believe when it wont calibrate, it’s because the rpm is not capable of reaching the targeted rpm that is specified. Example… it requires the rpm to hit (950 to 1050 “hit next” 1250 to 1459 “hit next” 2050 to 2250) don’t quote me on the numbers but you get the point. The other things it requires to calibrate where simple, like hydraulic temp above 104, engine temp above 140. Unfortunately without having the CatET yourself, you may have to ask the tech to get to the bottom of why it won’t calibrate.

Edit: I was able to find the thread I was referring to, but I don’t know the best way to link bear with me.

Thread titled “299C Loosing travel speed” https://www.heavyequipmentforums.com/threads/cat-299c-loosing-travel-speed.89079/#post-994581

 

[Quki22]

Thank you for the feedback Drago663. I greatly appreciate it. I completely agree that until the TPS is calibrated before moving on. Based on the the machines display RPM were within spec, both high and low. However in the diagnostics screen, the TPS indicated 35% with no throttle and 100% with the pedal fully depressed. I understand that although it provides this info the ECM maybe seeing something different.

Another bit of info, although this maybe normal, is the hand throttle has a “spongy” feel to it at max throttle. If you push it up all the way, you get slight resistance as if you were compressing a spring. When you release the hand throttle the handle will slide down a bit and stop. Maybe a change of 100 rpm. I guess what I’m trying to say is the handle throttle will not stay at the max throttle stop bracket. You can then press the pedal and get that rpm back.

It appears that the ECM is communicating with TPS which has me leaning towards cables, but not certain.

 

[Quki22]

But it’s really big $$$$ to have them come back out and I had already spent too much not getting anywhere, thats when I decided to try to get a CatET and calibrate myself.

How did you go about obtaining the software and communication adapters?

 

[Drago663]

Thank you for the feedback Drago663. I greatly appreciate it. I completely agree that until the TPS is calibrated before moving on. Based on the the machines display RPM were within spec, both high and low. However in the diagnostics screen, the TPS indicated 35% with no throttle and 100% with the pedal fully depressed. I understand that although it provides this info the ECM maybe seeing something different.

Another bit of info, although this maybe normal, is the hand throttle has a “spongy” feel to it at max throttle. If you push it up all the way, you get slight resistance as if you were compressing a spring. When you release the hand throttle the handle will slide down a bit and stop. Maybe a change of 100 rpm. I guess what I’m trying to say is the handle throttle will not stay at the max throttle stop bracket. You can then press the pedal and get that rpm back.

It appears that the ECM is communicating with TPS which has me leaning towards cables, but not certain.

The way I understand the tps calibration, and I am no expert so grain of salt and all that, I believe it doesn’t matter what the tps reads as long as you can hit the requested rpm in the calibration, thats why it has to be calibrated. So the computer knows what rpm to expect at what %. (Again sounds like the same problem as that forum I referenced.) As for the throttle handle, that pulls on the pedal, so as long as the pedal and throttle cable is setup, properly, the handle is none consequential. You could completely remove it if needed to eliminate it as a factor in calibrating the tps. As for it dropping rpm, you can Tighten it so it doesn’t loosen. Unless the drop in rpm is in the cable or linkage. Again it should be none consequential to the tps calibration

 

[Quki22]

No worries, I’m no expert either. From the service manual excerpts I found on the forum the TPS has to have a valid range between 5% to 95% duty cycle. I assume that means 5% to 95% of the 500Hz signal sent to the ECM.

So if I understand correctly, although the engine rpms, both low and high, are in spec if the TPS is outside that range it won’t calibrate. You think a worn cable might cause that?

Does anyone have the service manual section Systems Operation “Sensors”?

 

[Tyler d4c]

When I did mine I on the last step I had to give the linkage a bit of a nudge to be in spec. Probably not totally proper but it's been working fine.

 

[Nige]

I assume that means 5% to 95% of the 500Hz signal sent to the ECM.

The % is not determined by frequency (the frequency remains constant) but on the width of the square wave pulse, hence the name Pulse Width Modulated". See below.

 

[Quki22]

Thank you for the comments gentlemen. Nige, you are absolutely correct. After posting I started researching duty cycle and learned it’s the percentage of the time on just as the image you posted shows. I really appreciate all the assistance and guidance you guys have provided. I am really starting to lean towards a worn cable. That’s the only thing I can think of that that keeps the governor and TPS in sync within their respected tolerances. Thoughts?

 

[Drago663]

A worn cable, and/ or worn linkage on the pedal, its more complex than one might think.
Sounds like there might be something preventing your pedal from opening all that way.
I would disconnect the throttle cable from the governor (its really easy to pop off) and see if you can adjust the pedal to work within the tps % specs needed, that way you eliminated the cable as a problem. If you still can’t get the tps in spec, and the tps is new, the only thing left would be the pedal linkage I believe.

 

[Quki22]

When I did mine I on the last step I had to give the linkage a bit of a nudge to be in spec. Probably not totally proper but it's been working fine.

Tyler,

Please excuse my ignorance, when you say gave the linkage a nudge what are you referring to? Are you identifying the combination of the throttle pedal linkage and the pedal cable s the “linkage”?

I know that prior to taking the machine in the diagnostic screen showed the TPS % as 35% with the pedal up and 100% when fully depressed. Not sure how accurate that is as one poster mentioned that the display and Cat ET showed different readings.