D5g want speed issues

[Twinkie001]

I replaced both speed sensors in cat D5G dozer and it fixed the issues with the tracks acting a fool but it want go past about 1.7 or so speed. It will go down to 1 but not up any faster than 1.7 or so. The only codes it had were left and right track sensors. Do I need to get my macanic to calibrate them or is it somethingelse causing it?

 

[Nige]

Does it have any Active Codes right now.?

IIRC if the speed sensors you removed were the old type and the ones you installed are the new type (were the new ones Cat OEM and what Part Number were they.?) then the hystat drive train (pump & motor solenoid valves) will likely require calibrating. Post a Serial Number and I can look it up.

 

[Nige]

One thing I forgot to mention. D5Gs appear to be very sensitive to the alternator output being high enough, so you should check the fan belt tension and condition then after that measure altenrator output voltage. To be classed as acceptable it should be up at least around the 14.0v mark, or preferably higher.

 

[Simon C]

I like the idea of checking the alternator. There was a post a while back that had all kinds of posts on it to change this, and check that but nothing was presented about the alternator.
Then the poster responded that they changed the alternator, and all problems gone.
Not suggesting to change the alternator, just saying it does not take long to measure output with multimeter and clamp on with load on and engine revved up. Have found one that was dropping out 25 minutes into the test.
Have also seen one that was on the way out with 450millivolts of AC voltage leaking through the diodes.
Have seen too many Alternators plugged tight with dirt that took 2 minutes to blow out with 150 psi of air and then it can cool properly. People never check the alternator cable to batteries or starter post dependant on configuration and have seen them not able to carry the load.
Never mind the field call for overheat to find the alternator belt wrapped around the fan.
Yes good to check out alternators.
Simon C

 

[Twinkie001]

One thing I forgot to mention. D5Gs appear to be very sensitive to the alternator output being high enough, so you should check the fan belt tension and condition then after that measure altenrator output voltage. To be classed as acceptable it should be up at least around the 14.0v mark, or preferably higher.

Yes sir I checked it and actually put new belts on it before I replaced the sensors. I'll post a Pic of the serial numbers and the new part numbers. Thank you kindly sir.

 

[Twinkie001]

I like the idea of checking the alternator. There was a post a while back that had all kinds of posts on it to change this, and check that but nothing was presented about the alternator.
Then the poster responded that they changed the alternator, and all problems gone.
Not suggesting to change the alternator, just saying it does not take long to measure output with multimeter and clamp on with load on and engine revved up. Have found one that was dropping out 25 minutes into the test.
Have also seen one that was on the way out with 450millivolts of AC voltage leaking through the diodes.
Have seen too many Alternators plugged tight with dirt that took 2 minutes to blow out with 150 psi of air and then it can cool properly. People never check the alternator cable to batteries or starter post dependant on configuration and have seen them not able to carry the load.
Never mind the field call for overheat to find the alternator belt wrapped around the fan.
Yes good to check out alternators.
Simon C

The very first thing I did was blew all the dirt out. It was caked up with pounds of dirt. I blew it all out and put new belts on it cause the old ones were sqeeling. Turns out when my friend hooked to it to read the codes it had a low voltage code along with the speed sensor codes. The speed sensors have been acting up a while but it was very seldom but when the belts started squeeling it had the parking break and all messed up. New belts and clean alternator and the parking break worked fine but it was still pulling bad to the left and right. Now with the new sensors it's straight as an arrow just slow.

 

[Twinkie001]

Does it have any Active Codes right now.?

IIRC if the speed sensors you removed were the old type and the ones you installed are the new type (were the new ones Cat OEM and what Part Number were they.?) then the hystat drive train (pump & motor solenoid valves) will likely require calibrating. Post a Serial Number and I can look it up.

 

[Twinkie001]

My buddy is going to hook to it tomorrow and seen if it has any activie codes.

 

[Nige]

OK so the new sensors you installed are the latest Part Number. It may not fix the problem but until the hystat system pump and motor solenoid valves have been calibrated you can't be sure that they are not part, or even all, of the problem.

My buddy is going to hook to it tomorrow and seen if it has any activie codes.

You do realize that you can pull Codes from your tractor without a computer or Code reader...?
See the attachment starting from Page 4. All you really need is a paperclip or two.

 

[Simon C]

Glad I am not the only guy that finds alternators packed tight. The problem with it is that it causes the electronics inside to get hotter than designed for and shortens the life.
Not saying your alternator is bad but could start and turn RPM up and put your multimeter in "AC" mode and touch red test lead to battery output terminal of Alternator while putting black test lead on Battery Negative or a good ground. Cannot hook the Red Lead up to Battery positive as the battery will act as a heat sink and give faulty reading. On a 12 Volt system the maximum AC leakage is 500MV or 0.5 VAC.
On 24 volt system I am assuming it will be double. Most cars leak around 50MV AC to 200MVAC.
500MVAC means there is problems in the alternator.
Be interested to know how much yours puts out.
Nige is probably correct in Post #9 above in your needing to do some calibrating.
Thought if you are interested, you could test this.
Simon C

 

[CM1995]

Welcome to the Forums T001! Glad to have you.

Can't really add anything of value other than owning a D5G I bought new back in 2004 to now where it currently sits on a trailer needing to go to Thompson for calibrating.

Over the years we've had several problems with voltage causing all sorts of weird issues and a few calibrations along the way.

FWIW

 

[Twinkie001]

Glad I am not the only guy that finds alternators packed tight. The problem with it is that it causes the electronics inside to get hotter than designed for and shortens the life.
Not saying your alternator is bad but could start and turn RPM up and put your multimeter in "AC" mode and touch red test lead to battery output terminal of Alternator while putting black test lead on Battery Negative or a good ground. Cannot hook the Red Lead up to Battery positive as the battery will act as a heat sink and give faulty reading. On a 12 Volt system the maximum AC leakage is 500MV or 0.5 VAC.
On 24 volt system I am assuming it will be double. Most cars leak around 50MV AC to 200MVAC.
500MVAC means there is problems in the alternator.
Be interested to know how much yours puts out.
Nige is probably correct in Post #9 above in your needing to do some calibrating.
Thought if you are interested, you could test this.
Simon C

I will due that first thing in the morning. Thank you!! Man this fourm is awsome. I've read for years on here but never created a profile untill now. I should have done this year's ago!! Yall are full of wisdom and knowledge.

 

[Twinkie001]

OK so the new sensors you installed are the latest Part Number. It may not fix the problem but until the hystat system pump and motor solenoid valves have been calibrated you can't be sure that they are not part, or even all, of the problem.

You do realize that you can pull Codes from your tractor without a computer or Code reader...?
See the attachment starting from Page 4. All you really need is a paperclip or two.

Ok I'll get the codes tomorrow and go from there. I'm amazed at how knowledgeable you guys are sir. I'm really grateful to have input and guidance from you. Thank you!!

 

[Twinkie001]

Ok finally got mechanic to come back out and try calibrating the speed sensors. It wouldn't let him calibrate them due to it throwing up a solenoid code. It want tell him witch one. It just says code error solenoid s he's got to run them down now. Thanks for all the help!!

 

[Nige]

It wouldn't let him calibrate them due to it throwing up a solenoid code. It want tell him witch one.

He's not using Cat ET to read Codes I assume.?
Why not just pull the Codes using the Harness Code plug and a bent paperclip or two.? I take it he knows how to do that.?