PS2 engine speed surge

Sounds like you've checked all the usual suspects.

How often does the surge occur---every driver revolution or a longer period?   Is it at regular or irregular intervals?

Try it without the train behind it.  There could be a car with a problem. 

Does this occur only on curves?  If so, take the shell off and check for wires touching a flywheel or for a truck whose turning angle is restricted.

Check for a traction tire coming off.

sounds like the engine may be getting hot for whatever reason...  loose traction tire, over loaded on grades.  Does it feel warm or hot. any smell? Not good anyways.

are you running on DCS or conventional system?did you try reset threw DCS remote?

and what was the results!

?

Alan

Can you control the speed of the engine threw remote DCS?

Alan

I just spent some time checking out the suggestions. I did forget to mention that this surging is in DCS mode. I can control speed just like other engines.  I checked traction tires and all are in good shape. I did not notice any issues with the freight cars. I connected the consist to another PS2 engine and engine performed fine with no surging. Connected consist back to SD-9043 and surging was again present. It tends to pulse at around 5 second intervals both straight and curve. I took apart again and checked for free movement of trucks and any wiring binding; none seen. 

Engine does not seem warm at all. This being run on my outer loop which is flat and all 072 curves.

Alan, I did all my resets using DCS

I'd check for mechanical issues.  One of my favorites is a loose motor mount screw on the bottom of the truck, one loose screw = problems.  I've also had the two motor mounting screws in the mount itself loose and cause issues.

If you run this a lot may be time to clean the motors with an electrical contact cleaner.

Also how are the wheels and pick up cleanliness, especially outer wheels.  Dirty wheels can cause lose of power that has a greater effect under load.  Also loose pickup screws and terminal wire screws.  Things to check along wit other recommendations.

If still doing it I would watch with shell off to see if one motor is hesitating or not.  After that your chasing a bad board.  Either power supply or processor.  Definitely can be heat related.  G

I had that happen with a loco, and turned out to be long passenger cars and  close clearance on a curve.  But what you describe sounds like the speed control hunting.  Could be electronic, but could be an issue in a truck, with gear mesh.

I would say this would not be a tiu or remote issue, so no reason to do resets on them.  

Most certainly this is not a DCS issue or likely even an engine software problem. 

Thanks for inputs everyone. I did find one slightly loose motor mount screw but no change in performance after tightening some. I do run this some (miles is 577; chrono 56.13) but would not consider heavy use.  I have to finish up for today but will do a more thorough cleaning of everything tomorrow and Tuesday. After cleaning I will run with shell off to see if I observe motor hesitation or any other oddities.

RJR your description of "hunting" for speed control is very accurate description.

I will also run this with less freight to see if that changes performance, although I could not detect the hunting when it was run by itself.

Your last sentence indicates to me that the consist is suspect.  Uncouple the loco, and pull the consist with your fingers on its front coupler.  See if you see an occasional grab.  One thing dcs speed control will do is that if there is a brief grab somewhere, you will get a burst of speed.  

Make sure the motors are secure in the mounts, I've had the two little screws that secure them to the motor mount be loose.

For the hunting, I'd check the tach reader spacing and the condition of the tach tape.  It could be the tach reader dying, but I'd look for obvious physical causes first.

John you mentioned that earlier and Ken checked it.  One loose, but no change.  G

He checked the single screw under the truck, the actual screws that mount the motor to the motor mount can also be loose.  AAMOF, I chased that one a year back because I didn't check that.  I felt pretty stupid when I found it.

I had that once too,  Sure sign when the motor goes up and down on direction changes

I also had one doing the same thing and was a loose motor mount!

Good luck figuring it out , the A team is with you!!

Alan

To bring you up to speed since I last posted. I spent a couple of days doing a thorough cleaning of engine and freight including lube. While I had it apart I checked all of the motor mount screws and checked for any kind of binding either in gear train or in general movement of the truck. I found no issues on engine or freight cars. I ran the engine without the shell to see if I could observe any anomolies; again nothing found. In fact at 3 SMPH the engine ran fairly consistent and at 5 SMPH it was totally smooth.

I started adding freight cars and checking performance. It was after 7 cars were added that I noticed some "hunting". I changed cars out but that didn't seem to change anything. By the time I had 9 cars, the hunting was much more obvious. I used two other PS2 engines pulling the 9 cars and neither of them had any problems.

I think for now I will live with the current performance and limit to 6 car consist. If it gets worse then I will see about finding someone to work on it to fix the problem.

Thanks again for everyones suggestions. The one positive is I now the cleanest well maintained engine and cars I have had in a long time.

Ken

Hey Ken, while preforming your maintenance did you pull the motors out and check the grease on the gears?

Milwrd

No, just the side gears.  I did rotate the motors both direction by hand to see if I could detect any binding or hanging but could not feel anything. Also since it runs so smoothly at 5 SMPH I didn't think there would be any gear train issue.

 This helped one of my engines as it had really loose gears. BTW this engine has over 4k scale miles and gears still tight...and quiet.

Kenjr.  About what distance does the loco go between the speed drop and the ensuing surge.  If it's further than one circumferance of the driver, I would doubt it's a spur gear problem.  If you have modern cars and old postwar Lionel cars, make up a train of each; the loco has to pull harder to move the old Lionel cars.  I have a hunch that when there is a heavy load on the loco, one of the worm gears is forcing the motors shaft up and down, causing it to bind.  The heavier the train, the more force is applied to the ends of the motor shaft.  There can be considerable endwards force on the motor shaft, which could cause binding, tighter as the load is increased.

Just for kicks, which you have the shell off, pull one motor out, using masking tape tape it somehwere where it can't foul anything, and try running.  If the loco does this one on motor but not the other, we'll have pinned down the cause, or at least the location.

By the way, I'm going through a similar issue with a 1950 Lionel #736 that I converted to PS2, except my binding is at each turn of the drivers.

I have to travel out of town for a bit so it will be a couple of weeks before I get a chance to make some additional measurements and motor checks.