Cat prv 350l calibration....

[rmllarue91]

3ml365 machine had lots of electrical and hydraulic issues got most straighten out but it's acting like it won't save calibration. Machine is super slow in auto. If you switch to manual slow mode it's a little faster than auto. If your in calibration sub mode machine will respond to changing the two vaules but if you shut machine off or hold service key it goes back to super slow. I didn't have book with me and couldn't remember how to see if there's codes. I ordered a new prv valve. I will install check codes and try to recalibrate but was looking for some experience with this. Also if someone has experience with adjusting pumps i could use some pointers. I currently don't have a differential pressure gauge or large enough flow meter so I'm not sure how much I can do on this with just pressure gauges. Thanks hef

 

[r20d12]

Have you checked your powershift pressure with a gauge?
Does the engine bog way down when you operate functions?
Engine will die if you bottom out a cylinder?

I've never had to adjust pumps on one. Its always been a control issue or a failed pump.

 

[John C.]

Have you checked the engine throttle calibration first? The video below shows how to get into the A series monitor panels for diagnostics.

 

[rmllarue91]

I did check power **** pressure but don't remember once I get the calibration issue I'll re set power shift pressure.


The main issue I'm having is the prv valve won't hold calibration. On monitor panel when I exit calibration mode the prv totally destrokes pumps

When in calibration the two values for prv can be changed and you get set to where machine operates pretty good.


I did set the engine rpm to spec the speed sensor was bad in bell housing also

 

[r20d12]

Ok. I understand now. Im wondering if you have an issue with your CAN and CAT data link harness. I've not worked on a 350L but I saw no one else responded so Im just trying to help. Some machines will use one data link for calibrations and one for the normal machine function. Im wondering if the data link for calibration is working but the other one in not. Could be a broken wire or a failed terminating resister. There should be something in the fault codes leading you there. The "L" series is hard because the electronics were in their infancy and don't give you enough info some times. I hope this helps.

 

[John C.]

Checking fault codes is probably the logical place to start. Here is the menu part of the diagnostics. I don't have anything any deeper just yet.

Caterpillar Electronic System

Computer Controller Lights

• Yellow
• Monitor signal out, data problems
• Red
• Controller bad
• Green
• All OK.

Data Mode

• Push alarm cancel button and power mode until throttle indicator number shifts.
• Use power mode to cycle through the Data modes.
• The indicator lights on the left side of the panel will flash indicating the current mode.
• Power shift
• Engine Speed
• Engine coolant temperature
• Hydraulic oil temperature
• Analog/Digital conversion
• Real time Error codes (Each code will be displayed in order)
• Digital output (Use work button to set each of 21 points)
• Output Control Display Code
• To stop Data Mode
• Push alarm cancel till dial setting changes

Error Codes

• Push service button and power mode button until Mode 1 indicator comes on.
• Use AEC or washer button to cycle codes.
• To Clear
• Push AEC, Power Mode and Travel speed for about 3 seconds.

 

[rmllarue91]

Okay I'm at machine now if I check prv in data more it shows p17 as soon as a function is pulled witch equals no power shift pressure I'm plugging a gauge in now to teat accuracy. If you go into service mode you can change calibrations and it will work untill you log out of service mode. Also going to try the prv sweep test in few minutes

 

[rmllarue91]

Passes a sweep test voltage changes with calibrations and so does pressure out of calibration mode it's 30 psi power shift pressure. In calibration mode will go all the way up to 430 psi power shift that's way too fast lol this is with brand new prv coil and valve seems like it's controller.... No codes came back after I deleted history and no active codes while running. Any thoughts well come

 

[r20d12]

I think i said it earlier but sometimes, jumping between threads i get mixed up.

Some machines will talk through one data link during calbrations and another data link during normal operation. If the "normal operation" data link is defective that could explain your problem.

Ive had an ECM fail but thats an expensive part to just change if your not positive its bad.

If you have the schematic you should be able to see if it has two data links. On a newer machine, a code is given for any data link issue but anything before the C model is sometimes impossible to get the info you need.

I hope this helps you. Let us know

 

[TVA]

I think i said it earlier but sometimes, jumping between threads i get mixed up.

Some machines will talk through one data link during calbrations and another data link during normal operation. If the "normal operation" data link is defective that could explain your problem.

Ive had an ECM fail but thats an expensive part to just change if your not positive its bad.

If you have the schematic you should be able to see if it has two data links. On a newer machine, a code is given for any data link issue but anything before the C model is sometimes impossible to get the info you need.

I hope this helps

Usual suspect with “fast” network is terminating resistors!

 

[TVA]

All technician can do with CAN BUS is check wiring, powers and grounds, test resistance of terminators and that’s pretty much it. Calling an ECM bad - is a hard decision because it is expensive!

There’s one more thing you can do: if you have someone with two channel scope ( like friends who work at automotive dealer or shop who have the scope ) - connect to your network and look at the square waves - they should look square, clear straight lines and mirror each other, if not - try to unplug various ECMs and see which one distorts the signal. But checking for solid powers and grounds is a MUST. Very often ground gets loose or corroded at grounding lug on the body!

Sorry for intrusion!!!

 

[TVA]

One more thing: the “fast” network must have its terminators on the network harness, two of them usually 120 ohm each but connected parallel so you should have 60-70 ohm when you check. They look like empty wiring connector socket with epoxied end where usually wires coming in.
The “slow” network usually having its terminators inside ECMs.

 

[r20d12]

All technician can do with CAN BUS is check wiring, powers and grounds, test resistance of terminators and that’s pretty much it. Calling an ECM bad - is a hard decision because it is expensive!

There’s one more thing you can do: if you have someone with two channel scope ( like friends who work at automotive dealer or shop who have the scope ) - connect to your network and look at the square waves - they should look square, clear straight lines and mirror each other, if not - try to unplug various ECMs and see which one distorts the signal. But checking for solid powers and grounds is a MUST. Very often ground gets loose or corroded at grounding lug on the body!

Sorry for intrusion!!!

Good sound advice TVA! I had a snapon Vantage meter when they first came out. It was great for checking sin waves. It was 4000.00 back then. No telling how much now. It of course eventually quit working and all they wanted to do was trade it for a much more expensive one. Lol.

 

[TVA]

Good sound advice TVA! I had a snapon Vantage meter when they first came out. It was great for checking sin waves. It was 4000.00 back then. No telling how much now. It of course eventually quit working and all they wanted to do was trade it for a much more expensive one. Lol.

There’s actually a tool sold by Pico Automotive, it is NOT a scan tool but a scope interface for your computer, all it can do is put your voltages on the screen in a graph form, it is very good tool if you know what you doing. It is not cheap but not as expensive as full blown brand scan tool.

There also a lot more cheaper handheld two channel scopes, but those are limited in choice of resolutions and time frames and the big deal for me is I’m getting older and can’t see good anymore - so I need a big screen.

 

[TVA]

Good sound advice TVA! I had a snapon Vantage meter when they first came out. It was great for checking sin waves. It was 4000.00 back then. No telling how much now. It of course eventually quit working and all they wanted to do was trade it for a much more expensive one. Lol.

I never worked with CE brand scantools, do any of them have scope build in?

 

[r20d12]

There’s actually a tool sold by Pico Automotive, it is NOT a scan tool but a scope interface for your computer, all it can do is put your voltages on the screen in a graph form, it is very good tool if you know what you doing. It is not cheap but not as expensive as full blown brand scan tool.

There also a lot more cheaper handheld two channel scopes, but those are limited in choice of resolutions and time frames and the big deal for me is I’m getting older and can’t see good anymore - so I need a big screen.

That Vantage was a graphing meter but it was crazy fast and could catch even tiny glitches in the signal. I had an old Volvo A25C with a stupid transmission. I finally tapped into the engine speed sensor in the flywheel housing. The signal looked like a small child got ahold of a ball pint pen! Just funky scribble mars. When i removed the sensor the end was broke and it was just a ball of copper wire. Lol. New sensor fixed stupid transmission

 

[r20d12]

The Vantage was actually a scope and a volt meter. Was a fantastic tool!

 

[TVA]

That Vantage was a graphing meter but it was crazy fast and could catch even tiny glitches in the signal. I had an old Volvo A25C with a stupid transmission. I finally tapped into the engine speed sensor in the flywheel housing. The signal looked like a small child got ahold of a ball pint pen! Just funky scribble mars. When i removed the sensor the end was broke and it was just a ball of copper wire. Lol. New sensor fixed stupid transmission

And probably like it happens often - no codes?

 

[TVA]

One more, subtle one, Engine speed sensor give of believable but wrong signal, gonna have to use handheld rpm counter and compare it to what ECM reads.

 

[r20d12]

One more, subtle one, Engine speed sensor give of believable but wrong signal, gonna have to use handheld rpm counter and compare it to what ECM reads.

Yes. But not only speed sensor. A very common one is Cat D6 will get a crank but no start condition. No codes. But the machine will have been sitting there long enough to be cold and water temp will show in operating range! The ambiant temp is too cold for the engine to start without switching to its cold weather map so it wont change the timing and wont start. The first one i ran into kicked my butt! Didnt notice temp gauge till second day. Put a variable resister inline Turn it till temp read cold and engine started great!