Help Troubleshooting a Bobcat S70

[illerkayunnybay]

Hi everyone,

I ran into a bit of a problem while driving in my Bobcat S70 (Aw6 2010 series), it shut completely off, while driving down a hill, with a full bucket of gravel which caused to parking brake to engage. The end result was that the parking brake "assploded!!!" (I had to pick out pieces of brake disk and metal shavings from the bottom of the lubrication pan). I replaced the entire parking brake system (disks, solenoid etc) then started troubleshooting why it shut down in the first place. I found that the 25A ENGINE (F11 slot) fuse was blown. I replaced that fuse and the bobcat will now turn on but it will not start -- i.e. wont crank. Now this S70 doesn't have any safety equipment that would stop it from starting -- the safety equipment just disables the hydro. All dash lights on the bobcat indicate that the computer detects no problems. I replaced the starter earlier in the year along with all the axels and bearings, I have replaced all the fuses and magnet relays in the skid steer. The Bobcat information system isn't producing any error codes when the cat is turned to the ON/RUN position (all fans turn on, full pump turns on, the correct lights are illuminated, etc) just turning the key from ON to START wont produce a crank. Battery is new and fully charged. I've checked the battery connections and ground connections that I could find and they are all solid. I replaced the key-switch in case it had a dead spot as well.

Here is a confusing thing. If i turn the key from the full OFF to START, as fast as i can bypassing stopping at the ON position, the engine will turn over but only for a fraction of a second then nothing. I can't see any frayed wires and I have cleaned and checked all the connectors (I can get to) for damage, oxidation etc. The only different thing I see is the BICS black box has a flashing green LED on it (which may be normal I've just never noticed it). I would like some advice on how to narrow down this problem as my only option now seems to load the parts cannon with everything electrical and fire it at the bobcat from point blank range -- I have NO experience with diagnosing electrical problems so I don't really know where to start. I have the bobcat service manual, parts manual and operations manual but you could fill a swimming pool with the amount of information NOT in those manuals. Thanks in advance.

 

[Arny L]

Sounds like ignition switch might be gone. Get a helper to sit in cab, have them turn ignition switch to crank position. With a test light, or volt meter, check for 12 volts at the starter solenoid wire. This is the wire beside the large battery cable, that is attached to starter.

 

[crewchief888]

loose/corroded battery connections

 

[illerkayunnybay]

Replaced the ignition switch with a brand new one, new battery and cleaned and attached it checked terminal wiring. Verified that all frame grounds are connected. -- same problem. Checked solenoid wire for starter, has continuity and 12v. Again I have power to the machine when it is in the on position just no start. If I turn it from the off to the start as fast as i can (i guess faster than the on-board computer can boot up?) it will crank for a moment then stop.

 

[Arny L]

Try checking starter relay for burned terminal, or swap relay with another. So when you turned ign switch to crank, you had 12v on solenoid wire, was it disconnected from solenoid or atteched.

 

[Arny L]

Without a wiring diagram, we’re kinda guessing. If your starter relay ground circuit is computer controlled, then you could be losing the ground side, by way of green corroded wire that fails under load.

 

[illerkayunnybay]

thanks, ill look into that.

 

[ozarkag]

Fuse doesn't blow again?
And which bics light blinks?

Looks like that machine does have a controller, so any fault ( say fuel solenoid) could prevent cranking

 

[Ridinhigh1500]

Does it have the little Kohler diesel engine that looks like a lawn mower engine?

 

[crewchief888]

maybe the starter is junk. try spinning it over at the starter with a screwdriver

 

[mybmw]

Hey guys I have a similar problem with my bobcat S70, when I turn on ignition I hear a click from the starter but it will not crank, I have changed the battery, ignition key switch and the had the starter reconditioned it is still the same, I have checked the ignition wire coming into the starter it seems to have no power I have checked fuses and swapped relays but still the same, however I can start it when I jump start from the thick starter cable to the skinny starter cable then she fires up any suggestions as to the cause will be greatly appreciated thanks in advance regards Frank

 

[illerkayunnybay]

Hi everyone,

I ran into a bit of a problem while driving in my Bobcat S70 (Aw6 2010 series), it shut completely off, while driving down a hill, with a full bucket of gravel which caused to parking brake to engage. The end result was that the parking brake "assploded!!!" (I had to pick out pieces of brake disk and metal shavings from the bottom of the lubrication pan). I replaced the entire parking brake system (disks, solenoid etc) then started troubleshooting why it shut down in the first place. I found that the 25A ENGINE (F11 slot) fuse was blown. I replaced that fuse and the bobcat will now turn on but it will not start -- i.e. wont crank. Now this S70 doesn't have any safety equipment that would stop it from starting -- the safety equipment just disables the hydro. All dash lights on the bobcat indicate that the computer detects no problems. I replaced the starter earlier in the year along with all the axels and bearings, I have replaced all the fuses and magnet relays in the skid steer. The Bobcat information system isn't producing any error codes when the cat is turned to the ON/RUN position (all fans turn on, full pump turns on, the correct lights are illuminated, etc) just turning the key from ON to START wont produce a crank. Battery is new and fully charged. I've checked the battery connections and ground connections that I could find and they are all solid. I replaced the key-switch in case it had a dead spot as well.

Here is a confusing thing. If i turn the key from the full OFF to START, as fast as i can bypassing stopping at the ON position, the engine will turn over but only for a fraction of a second then nothing. I can't see any frayed wires and I have cleaned and checked all the connectors (I can get to) for damage, oxidation etc. The only different thing I see is the BICS black box has a flashing green LED on it (which may be normal I've just never noticed it). I would like some advice on how to narrow down this problem as my only option now seems to load the parts cannon with everything electrical and fire it at the bobcat from point blank range -- I have NO experience with diagnosing electrical problems so I don't really know where to start. I have the bobcat service manual, parts manual and operations manual but you could fill a swimming pool with the amount of information NOT in those manuals. Thanks in advance.

UPDATE:
After tons of work narrowed it down to the computer as the problem. Had to take it into the shop for them to run a diagnosis on the control module and it was just spewing random data. Replaced the control module and the main wiring harness/fuse box (as the wiring and fuse box were showing some wear) and the problem is now fixed. For troubleshooting purpose all the voltage drops and voltages at the fuse box were fine and I could find no continuity errors in any of the main wiring systems, basically it was a process of elimination that led to me picking the "black Box" as the source of the problems. If I removed the fuel solenoid and manually powered the starter, the system would run.

 

[Awlucio]

Hey guys I have a similar problem with my bobcat S70, when I turn on ignition I hear a click from the starter but it will not crank, I have changed the battery, ignition key switch and the had the starter reconditioned it is still the same, I have checked the ignition wire coming into the starter it seems to have no power I have checked fuses and swapped relays but still the same, however I can start it when I jump start from the thick starter cable to the skinny starter cable then she fires up any suggestions as to the cause will be greatly appreciated thanks in advance regards Frank

Hello Frank, seems similar to the issue I am currently having. Were you able to resolve it ?

 

[Rjtoocool32]

Hello Frank, seems similar to the issue I am currently having. Were you able to resolve it ?

Did you figure yours out? I can assure you if the symptoms are similar in any way to, no crank no start, then it's likely the gateway computer.

I went through everything here in this thread and once I downloaded the manual for $20 I could see that ALL of the wiring, goes through the gateway. It's stupid because you can run it, just fine if you jump the starter and remove it loosen the fuel solenoid. Then push it in to kill the motor.

I have the manual and wiring diagrams if you want them. I did the tracing myself at first with an electrical line tracer. Once it appeared it all goes through the computer I purchase the manual to be sure. And that's how it works. It's stupid because I could hardwire this entire thing with the safetys AND it would ruin just fine without the gateway. I'd rather have that kinda of setup.

Anyways I'm pretty sure you should be thinking computer. Especially if you remove the fuel solenoid (that's under that cab after you tilt it back) and crank with a screwdriver. With the key on, it will start. Then you know it's the computer. All of the safetys are only there to keep it from moving, not starting.