• sd60 low hp under self load

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Discussion of Electro-Motive locomotive products and technology, past and present. Official web site can be found here: http://www.emdiesels.com/.

Moderator: GOLDEN-ARM

  by dieseldodge
Under self load, load regulator starts to derate under 4 throttle all the way through 8 throttle. There is no hp improvement after 45 min of load testing in 8 throttle. Load reg. 80%, hp 3045, fuel metering is at .96 on the gov. quadrant. Return sight glass is clear with 40# of fuel pressure. 14# of airbox pressure. Does anyone have any suggestions on were to find the needed hp? Thanks
  by WVU
The Load Regulator on the SD60 has to be in Full Maximum Field to make the proper HP. The excitation system is designed for the load regulator to operate there because it establishes the KW Ref. The KW Ref that you want to see in notch 8 is 2686. Take 2686 and add three zero's to it 2686000 and divide by 700 and you should be making 3838 Horsepower. When the load regulator backs out on these units, it will weaken the KW Ref and of course you will not make the horsepower you are wanting to see. From my experience over the years, I have had several SD60 units have the Load Regulator back out in notch 6. With this exception for notch 6, all other notches will remain in full maximum field at 100%. I am sure that you know that when you put the SD60 in notch 8, sometimes it may take 5 minutes or so to reach full horsepower and this is normal. Fuel Pressure on a SD60 should be around 55 psi +/- a little. On the SD60 they have a Spring Loaded Fuel Drain Relief Valve on the Fireman Side down low between the Fuel Pump and the Air Compressor. Sometimes when a SD60 has been serviced, people forget to release the fuel drain valve back to its normally closed position. The Fuel Pump on the SD60 should be atleast a 7 gallon pump. The Governor Quad should be running at .82 on these units with 904 Engine RPM's. Rule of thumb, when your load regulator is backing out, it is mostly a mechanical problem. Take a heat gun and shoot your stack temperatures for each power assembley and make sure that you do not have a cold stack. If you have a cold stack, you might have a bad injector. Always make sure that your exhaust valve bridges are not too tight. They should have a 1/16 inch of clearence if I remember correctly. With the unit in idle, open each Power Assembley Test Cock one at a time and listen for the sound. They should all sound about the same. If one is noticabley different, you might have a exhaust valve that is set too tight. You could also be about to drop an exhaust valve also. Always remember to check your Racks. You will need a Rack Jack and a tool to set them. Dial your Governor Quad in on 1 inch with the rack jack and with your adjusting tool check each rack to be set at 1 inch. To adjust the rack you will need a 7/8 wrench to break loose the jam nut. Other things you can do is, with the unit idling, you can pop test the PA by removing the pin out of the monkey tail and push the metering rod in all the wall and listen to the sound of the PA. They should all sound the same.
  by WVU
I forgot to add from the previous post that you need to make sure the unit has the proper engine components. the Governor should be 0041389 and the Injectors should be 0044488 and the Turbo should be 0031530. I check some of my information and the Fuel Pressure in Idle should be around 50 psi and in notch 8 it can drop down to 43 psi. Over the years I have also noticied that sometimes in selfload on a SD60, the unit will make Horsepower even with a .94 rack on a .82 Governor and I cannot explain this. This has puzzled me for years. A good Turbo Pressure on this unit is around 30 psi in notch 8. Another thing to check is your Air Fuel Limiter Line that is a 1/4 inch flexible line that runs from your Airbox up to you governor. If the line is plugged it will cause you HP to be low. With the unit in Notch 8, disconnect the Air Fuel Limiter Line from the Governor and if the unit runs even worse, that will not be the problem. Eventhough I doubt that this problem is electrical, you might try a FBE card when you cannot get a 100% Load Regulator in any throttle notch. Another rule of thumb if you are not making Horsepower and your Load Regulator is staying in Full Maximum Field at 100% more then likley the problem is electrical.