Hydro Ax 670 Low Power

[Jtwischermann]

I need help troubleshooting a low power issue I'm having with a Blount 670 Hydro Ax with a Fecon head. Machine has about 9000 hours. I know nothing about it other than the engine was replaced a couple years ago. 

When using any hydraulic function other than drive and steering it will bog the motor down a lot. When turning on the head it bogs the motor down from max rpm to probably less than 1500 rpm (no tach so I'm just guessing) lifting or tilting the head does the same but not as bad. If you get into a tree and start grinding there is very little power and if you try to lower the head into the tree too much at once or tilt it as well as drive forward at the same time it will stall. Forward and reverse also seem a little weak but I don't know, I've never even seen one of these machines until last week. 

I don't know when the issue started, I was brought in to finish a state contract with it but there's no way I can get it done with the machines poor performance.

I've changed all 5 hydraulic filters I could find, that made no difference. I tipped the cab up and visually checked all the wiring and found no issues. 
I don't have a pressure gauge but I'm going to try to buy one today. 

Anything else I should be checking besides pressure? What should pressures be and which test ports coincide to which function?

Also if anyone has any wiring schematics or service manuals I'd be interested in them. I've got some engine wiring that is just hanging down near the alternator, two wires are grounds and two are 5 volt but I can't find anywhere they would attach.

[mike_belben]

What engine is in it?  When you try to drive up a hill without doing any other function, does it have the power or lug down and try to die out?   Does it billow diesel smoke under load and if so what color?

When its bogging down is the exhaust note farty and rumbly?  

Im trying to figure if this is low engine power or extreme hydraulic demand.  If a compensating swash plate pump is not destroking to maintain whatever spec its designed to maintain youll get severe load.  Itd be like trying to climb a hill in 5th gear towing your camper and refusing to downshift.  Theres a lot of ports and parts in a compensating pump and you really need to get the service specs from the pump manufacturer.  Look hard for some part numbers on the pump and google until you find something.


Two guys thatre really good with this are @kiko and @treemuncher

[kiko]

I have worked on hydro-ax Mach me for 30 odd years , if a service manual exist I have never seen it.   The issue with your boom and tilt loading the engine is because the main relief or the port reliefs are set below the pump POR.  The boom tilt and steering work off the same pump through a flow priority valve. So if steering works fine the pump is ok.  This will load the engine because it makes the pump go full flow.   When you open the front cover where the valve bank is there should be a sticker on the left hand side that has the pressure specs for each function.   Now to the engine,  there are certain engine codes that will cut the horse power in a limp home manor to keep it from being operated.  There should be a small digital displace on the left hand side of the dash. Does it have a small yellow light on , or a red light.  If so it has engine codes that need to be resolved.  I can't tell you exactly how to pull the codes but it involves holding the up and down arrow at the same time.  If you do find  codes please post them . They will be in the SPN FMI format  like SPN 1077 FMI 12. The drive function is  a closed loop circuit with a pump and motor.   The third pump is for the mulcher head and is likely a closed loop circuit as well.

[treemuncher]

First thing I'm thinking is fuel filters. In low range, unless you are in mud or steep ground, there is not a lot of pull on the hydraulic functions. Troubleshoot the basics, first. Air & fuel filters. Exhaust colors, test temp of each cylinder output on the exhaust manifold, turbo pressure, etc. Oil in the pump driver splitter box at correct level and running a reasonable temp?

After that, start looking at the hydraulic circuit. Isolate which circuits are causing the symptoms then check temperatures of the output lines for anomalies, back pressure on the return filters, oil condition, etc. It's all basic hydraulic and diesel troubleshooting to get it figured out.

A non contact temperature gun or infrared camera can be a lot of help it these situations. After you isolate the problem area, then you can figure what is causing the issue.

[Jtwischermann]

Thanks for all the replies, I've done some more troubleshooting and found the turbo had excessive shaft play so I replaced it with another used unit I had laying around.
It's got a 24 valve Cummins with the vp44 injection pump. Fuel pressure is at 12-15psi under load so that's good. Filters are all new. After replacing the turbo im seeing 11psi of boost max, the old turbo was barely pushing 7. Still seems to lack power, definitely better but I think I should see at least 15 psi or so?
 After speaking with some people that know a bit more about hydraulic systems im leaning more towards lack of engine power being the issue. There is no excessive black smoke, no blue or grey at all.
 I figured out how to pull codes and there is a long list of them. I believe the first three or 4 were active the rest were stored.
SPN FMI
100 4
190 2
111 2

105 16
1383 31
100 1
620 18
100 18
111 1
110 16
626 11
632 11
168 18
1077 9
627 2

[Jtwischermann]

I was given a little history on the machine, the engine was replaced with a used unit and whoever swapped it was a hack. There's wires cut, bolts missing, etc. There's 5 wires on the exhaust side of the block that are not hooked up, I believe one is oil pressure, the other 4 are cut and I have no clue what they're for. Two are ground and two are 5 volt so I'm assuming they go to a sensor but there's nothing close that they would go to. 

I know little to nothing about hydraulic systems, but it seems pretty straight forward. It's just overwhelming when I see 100 hydraulic lines all weaved together and don't really know what each on does.
 I'm proficient with Diesel engines but have an electronically controlled engine with no way to scan the computer is leaving me dead in the water. The machine is on a ranch about an hour from the nearest podunk town and I have no way to haul it to the shop so this is all being done in the field. 

Is there a way to clear the codes without a scan tool? 

I'm thinking that there could either be an issue with the map sensor or injection pump, maybe some knowledge of the codes may help. 

[mike_belben]

Throttle position sensors commonly use 5volt reference signals.  And those injector pumps have a pretty low reputation.  I dont know that fuel sustem at all but lack of fuel will lower the boost numbers and egt.

[kiko]

100 4   oil pressure sending unit voltage high.   Sensor wire not connected or sensor bad.  No affect on engine power 
190 2   no engine speed detected. The engine speed sensor is located in the front gear train cover just below the injection pump. Will put engine in derate horsepower .
111 2 low coolant level, will also result in derate.

A computer would be of no use .  You just need a wiring schematic  along with the codes.   And no need to clear the codes. Once the issue that caused the code is repaired the code will become inactive and will no longer affect engine performance.

Also the 670 seventy had overlapping sensors.  The one for the computer which will show up on the digital monitor and the other is for the anolog dash gauges.
If you look directly below the ecu you will see the Cummins oil pressure switch with one wire  ,  to the left in the next oil galley port is the anolog oil pressure sender which is shaped like a bell.

[Jtwischermann]

100 4   oil pressure sending unit voltage high.   Sensor wire not connected or sensor bad.  No affect on engine power
190 2   no engine speed detected. The engine speed sensor is located in the front gear train cover just below the injection pump. Will put engine in derate horsepower .
111 2 low coolant level, will also result in derate.

A computer would be of no use .  You just need a wiring schematic  along with the codes.   And no need to clear the codes. Once the issue that caused the code is repaired the code will become inactive and will no longer affect engine performance.

Also the 670 seventy had overlapping sensors.  The one for the computer which will show up on the digital monitor and the other is for the anolog dash gauges.
If you look directly below the ecu you will see the Cummins oil pressure switch with one wire  ,  to the left in the next oil galley port is the anolog oil pressure sender which is shaped like a bell.

Thanks kiko,
Looks like there's no oil pressure sensor on the block anywhere, neither the factory two wire cummins or the single wire switch. Camshaft sensor is in place and plugged in. I'll ohm the wires to the computer and swap the sensor if needed. Coolant level is good so I'll have to check wiring to the level sensor. 
Thanks again for all the help!

[Jtwischermann]

Kiko,
Is there any way to be sure if it's in de-rate other then power loss? The owner of the machine has had it for a few years and says it's never had any more power then it currently does, even before the engine was swapped out.

Also would you happen to have the pin outs for the coolant level sensor and/or the cam sensor?
The coolant level sensor wiring looks like the fan ate it and it must have ripped the connector off when it did. I can get a connector but I'm not sure what wires go where. I have 3 white wires and one red. I jumpered 2 whites together and 1 white to the red and the 111 2 code went away but shortly after I got a 111 1 code.

I swapped the cam sensor out to no avail, and I'm unsure which pins to ohm the wires to the computer.
 I'm wondering if the used engine that was installed has a different cam gear that the sensor can't read but I'd like to exhaust all other options before digging into that.

If I could get this thing into a shop I'm sure I'd have it all sorted out by now but working on this thing outside when it's been averaging 15 degrees out with 40+ mph winds is really sucking the ambition out of me.

[kiko]

The 190 and 111 codes will most definitely cause the engine horsepower to be lowered.   These must be resolved to diagnose any other low power issues. I have the wiring schematic for this engine.   I will dig it out.

[Jtwischermann]

I forgot to mention, the display that you read codes on shows engine rpm, so I'm not sure why it would be throwing a code for engine speed? Is there more than one place it pulls engine speed from?

[kiko]

I have been unable to locate this schematic yet.  Found all the others. It is tucked in the tigercat 620c service manual I believe which is Mia. I will continue to look. 

[kiko]

I found the schematic today if by chance you still need those pin outs. It was tucked In the Ranger H67 service manual.   .

[Jtwischermann]

I found the schematic today if by chance you still need those pin outs. It was tucked In the Ranger H67 service manual.   .

Yes I sure could use it. 
Any idea why it would read rpm in the digital display but still be throwing an engine speed code? Is there another sensor other than the camshaft sensor on the back of the timing cover?
 I think there is a spot for a crankshaft sensor on the intake side of the block but it's got a plate over it. 

[kiko]

So if you have the vp44 injection pump. There should be a crank position sensor.

 

 

[kiko]

The cam position sensor is inside the injection pump as the pump drive gear is the same diameter as the cam gear. The engine speed sensor is under the injection pump and the crank position sensor is toward the rear of the block.  If you remove that cover you should be able to see the time wheel on the crank shaft. That crank sensor needs to be there.

 

[kiko]

So sometimes the generic spn/FMI  format gets mis translated.  The Cummins code is 115.  Google it .  It deals with signal lose from the crank or cam position sensors or both.  

[Jtwischermann]

So sometimes the generic spn/FMI  format gets mis translated.  The Cummins code is 115.  Google it .  It deals with signal lose from the crank or cam position sensors or both.  

Great, thank you very much. I'll find one and throw it in there and hopefully solve the issue.