How's it going? I am working on sd40's in Australia and have a few issues with some of them. I won't go into them all yet but one in particular under load, both on track and test goes ok up to notch 6 then dies in 7 and 8. Have been through a lot of fault finding and it appears not to be electrical. Any feedback would be appreciated. Thanks.
Loey
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Darren (BLHS & CRRM Lifetime Member)
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I am not involved on locomotive maintenance - however, SD40's and any other locomotive that does not load fully at it's maximum throttle position has a defect. I have no idea where to tell you to look for it, but there is a defect.
Never too old to have a happy childhood!
Do you get engine speed the gen field switch down? If you still get shutdown with no load, then I'd look at everything from the throttle switches to the governor solenoids.
If it's under load, is there black smoke? Clear stack? Solid fuel in the sight glass or bubbles? Where it the rack during this? Load regulator?
Mechanically, if things are normal in notch 6, I can't think of any mechanical problems that would cause shutdown in 7 & 8 - you should still be able to run, just with degrade HP.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Hey Don
It runs fine with no load and we have had the load regulator off and manually operated it whilst notching it up all the way to 8. It doesn't fail totally but struggles and only reaches 1.12 on the rack angle indicator. It's balance point is .82.
With the LR back on and notching up from six to seven and watching the LR, you can see it isn't being driven back at all. It stays at full excitation. I'm thinking possible mech Problem maybe in the gov???? as it isn't sending any oil to the vane motor. Why???? This the million dollar question.
Cheers
It sounds like the governor is not adjusted right. If it is shutting down automatically then something is being tripped after a certain RPM. Instead of using the throttle notches I would use the lay shaft lever for the throttle. Then you can slowly bring the RPM's up and if it is tripping something you will figure out about where it is tripping. Low oil and water will also bring the engine back to idle.
It could also be a weak fuel pump. A weak fuel pump would be able to keep the engine running until a point and then it would sputter when you get up into the higher notches.
A build up of excessive carbon in the exhaust ports would limit exhaust gases and cause the engine to run rough. But it would have to be really plugged up.
If the engine is running off of blowers the blowers could be worn out and not producing enough air to clear out the cylinders.
It sounds like a minor problem to me. I don't think it is electrical related. You can buy the GM 645 manual off of Ebay which should help you more.
Check the Fuel lines look for any Rubber lines in them. Replace them your getting a Fuel Starvation problem in the Motor. The Newer Fuels recat with the Rubber and cause it to Swell SHUT at lower Flow Rates it will be fine however at higher rates it will NOT get enough Fuel to the Injectors. Check for Suction Leaks in all Fuel Lines also be amazed how a little air will Screw up a Motor.
Had a 8/71 Detroit doing the Same thing to me about 19 Years ago to me Bossman was pulling his Hair OUT. What was the cause of it a flap in a fuel line that a Lower RPM would stay up and at HIGHER RPM would come down and cause the Engine to do the EXACT things your describing. The 8/71 Detroit is a 2 Stroke OTR motor that shares alot of Design work with the Larger EMD models.
Loey Hey Don It runs fine with no load and we have had the load regulator off and manually operated it whilst notching it up all the way to 8. It doesn't fail totally but struggles and only reaches 1.12 on the rack angle indicator. It's balance point is .82. With the LR back on and notching up from six to seven and watching the LR, you can see it isn't being driven back at all. It stays at full excitation. I'm thinking possible mech Problem maybe in the gov???? as it isn't sending any oil to the vane motor. Why???? This the million dollar question. Cheers Loey
With the load regulator disconnected, you should be able to put it in N8, get 904 RPM, and crank the LR manually until the rack got to .82 and you were making 3000 HP.
If it were the fuel pump not being able to keep up, the engine would start to bog down and the rack would go past .82. Since the rack only gets to 1.12, that makes me think it's the governor. If it were the rack linkage is binding, then the governor would back off the LR in order to keep 904 RPM, not cause a shut down.
Can you try a governor swap from another unit?
on the BN we used to get this to happen when the air filters were plugged, especially with leaves and debris.
trainguy21 on the BN we used to get this to happen when the air filters were plugged, especially with leaves and debris.
That should give you turbo surge, at least for a while. Lots of black smoke when the compressor on the turbo can't hold the pressure differential between the airbox and the inlet. Air rushes backward thru the compressor, then the compressor starts working again, building up airbox pressure until the cycle repeats.
What is the airbox pressure?
What is the fuel pressure?
Reconnect the load pot and see what is the MAXIMUM HP before the load regulator balances.
Does this engine have the "slammer"? ( a device that shuts the air off to the turbo , pull the air filters and see if there is a device mounted on the wall behind the filters).
Verify at the governer plug that all the solenoids ABCD are working in notch 6 then verify that the solinoids are working in notch 7-8. Make sure that the ER relay is staying energized other wise the only solinoid that will be active is D solinoid - the shut down solenoid.
Make sure the FPCR relay is staying energized.
Does the engine have all of its speeds without the engine loading ? If not junk the governer.
Randy
Somebody actually purchased and installed Slammers? Interesting......
He said he had engines speeds at with no load, so solenoids should be OK...
Would really like to know what the stack looked like while loading.
The ATSF SD45s that the WC bought had the slammers. The engines shut down for no apparent reason , we had a devil of a time figuring that one out. Almost as bad as a plastic trash bag in the fuel tank.
Randy Stahl The ATSF SD45s that the WC bought had the slammers.
The ATSF SD45s that the WC bought had the slammers.
Hello Loey,
Please check if fuel filters and air filters are open and not clogged. If the loco runs well on other notches, probably some obstruction on fuel pipeline can be occurring, ( maybe some cloth or cotton fiber in fuel tank can be aspirated and closing the main pipeline when more power is recquired from Diesel engine.)
Newton
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