Cat d5g ignition diagram with prelube

[Brian Sanders]

I have a cat d5g sn 5XK37095 that will not consistently start. The parking brake light on dash goes on and off (with the switch)so I don’t believe that is the issue. Batteries are new and charged and when I jump the start relay? (12v directly to starter solenoid wire By the circuit breakers) it will start right up. The prelude system is working and building oil pressure just no 12v to the starter solenoid to crank. I know it’s a loose wire or bad relay or solenoid but having a hard time following the wiring. Does anyone have a wiring schematic for this thing? Thanks in advance!

 

[Nige]

I have a cat d5g sn 5XK37095

That’s the engine number. The machine number will be on the line above it on the data plate.

 

[Deimos]

What Prelude system are you talking about? According to the electrical diagram for your tractor's serial number, the Prelube system (pre-start engine oil priming) is not present.

 

[Brian Sanders]

Sorry about that, serial number is
CAT00D5GPFDH01718

 

[Brian Sanders]

Sorry about that, serial number is
CAT00D5GPFDH01718

 

[Nige]

As @Deimos pointed out there is no prelub system listed for that machine, either as an option or not.
Do you have any photos of what's installed.?
Is the prelub pump part of the starter motor or separate.?

 

[Brian Sanders]

I believe it is separate and mounted towards the front right of the engine. I will get some pics and update the post.

 

[Brian Sanders]

View attachment IMG_3734.jpeg

 

[Brian Sanders]

View attachment IMG_3736.jpeg

 

[Brian Sanders]

PicView attachment IMG_3737.jpeg

 

[Brian Sanders]

It could be an add on after the factory. We bought the machine used and unsure what previous owner had done to it.

 

[Nige]

It could be an add on after the factory. We bought the machine used and unsure what previous owner had done to it.

I would say it is, because the electrical schematic doesn’t show it. Let me take a look around for anything that may mention it. It kind of looks professional but I’m not convinced that it is factory.

BTW your second photo shows a fair bit of butchery to the electrical system by the flywheel housing.

 

[pittsburgh cat man]

That looks aftermarket. Can't sat i ever saw a prelube system on that small of a tractor

 

[pittsburgh cat man]

Just thinking is that a quick oil change set up I think I would trace the hoses off the pump

 

[Brian Sanders]

Well I think I can figure it out if I have the wiring diagram (even if it doesn’t include the prelube). Yes there is a lot of butchery on the wiring harness, I am just trying to figure out at what point it is losing the starter signal. It looks like an aftermarket solenoid has been added above and to the left of the starter, but I am not an expert on these things.

 

[Brian Sanders]

View attachment IMG_3735.jpeg

 

[Tyler d4c]

Appears yours got a new crank case in there some one was/ is trying to prevent it from kicking a rod out. Tge 3 or 4 of those engines ive dissassebled tgat where blown up all had the rod nuts unscrewed laying in the pan.

 

[Simon C]

Picture 3737 states that when you turn the key to start the pump will activate until sufficient pressure is reached and THEN the starter will go. Tells me there has to be some kind of oil pressure switch that has to close when pressure is reached, that may then energize a solenoid or relay that then powers up the starter "S" Terminal. If I was installing a system like that it would have something like that for control of starter S Terminal. Check for a oil pressure switch with some non-oem wiring attached to it.
Something controls that pump.
Simon C

 

[Brian Sanders]

The engine has been basically replaced… we had an incident where I believe it was overfilled with oil and the block cracked (out the side) and ended up getting replaced. Supposedly with all cat parts. It has had a lot of work done to it, just trying to figure out the starting problem.

 

[Brian Sanders]

Picture 3737 states that when you turn the key to start the pump will activate until sufficient pressure is reached and THEN the starter will go. Tells me there has to be some kind of oil pressure switch that has to close when pressure is reached, that may then energize a solenoid or relay that then powers up the starter "S" Terminal. If I was installing a system like that it would have something like that for control of starter S Terminal. Check for a oil pressure switch with some non-oem wiring attached to it.
Something controls that pump.
Simon C

The thing is, when it works correctly (1 out of 10 times), the oil pressure will get to about 20psi and fire up no problem. Other times it will run until the oil psi gets to 30+ and keeps building pressure without starting … I think the prelude is working, it’s just that the starter isn’t getting the signal to fire…