Issues Upgrading MTH premier Dreyfus from 2000

the way the flywheel looks backing down the hill in the video, it appears that maybe something is worn out? Seems like excessive wobble in that area?

Might be driving the tach reader circuit nuts?

How does it feel when you rotate the flywheel by hand? Is the motor shaft real loose? U joints? etc.?

Can you feel roughness?

How about going down a hill forward, same issue?

Joe,

Tbe dog bone and cups do not look to be worn out.  Units feels very smooth when rotated by hand.  I believe the wobble is from the control loop in the software stopping and starting the motor too aggressive but not sure.  This was not an issue with the original 5v ps2 board.

John

Yes, same issue when going forward down the hill 

Well? It could be the board. I just feel that the spinning flywheel looks rough.

Maybe you have a wire that's not right? Maybe you could send the board to G for testing?

or.... Do you have another engine you could place this board set into and check it's performance out for this issue? (rule out the board and pinpoint the issue's source)

Joe, he stated he replaced the boards one at a time and still had the same issue.

I'd probably swap out the tach encoder, though I can't imagine why that would fail only in one direction. 

Sorry, I missed that. I don't like messing with the board set like that. I swap out the pairs as I'm not good working with separating them.

I had an engine where the tach reader worked before. When I put in another board set, it acted like it didn't like the signal from the reader. I swapped out the reader and all was fine. 

I had replaced the tach in the past with no improvement, but had not replaced it recently since I restarted.  The unit has the same issues when going forward down hill, so I don’t think it is a directional thing.  I will try to dig up another tach and replace it again.

i was thinking that maybe since this was one of the firat dcs engines out there may have been some uniqueness to how it behaves mechanically requiring a special sound set file.

You're replaced the boards, so you're running out of options.  I'd consider the tether, but since backing down a hill or going forward down the hill do the same thing, I'd think the flexing would even out.  I'd consider the motor, but the 5V and 3V board should have similar operational characteristic.  Also, it's a Pittman, those are pretty close to bulletproof.

If the tach reader doesn't do it, I'd be looking very closely at the rods, have you tried holding the non-driven wheels back while rotating the motor?  Maybe when they're being pushed into the gear driven wheelset, that's when the friction and bucking occurs?  What you have appears to be a mechanical issue, but it's hard to tell in one video clip.

The only thing we can do is suggest the troubleshooting direction from what we see in this video. The flywheel's wobble or jerkiness seems to be in time with the sound of the issues. The gap of the tach seems tight. Stated fact that the engine struggles on hills with speed control.

 You replaced the boards and tach with what we have to guess are good ones. There's not a lot else we can guess on. Only the wiring and mechanical is left.

There are times where it's something different that pops up like power pick-up issues or similar so you have to be open to look at anything. The fact that it used to be OK with the 5 volt doesn't rule anything out here. So don't think that an issue that wasn't present before, is caused by the new board. It could be components not getting along or it can be from a new issue that developed.

Unplug the smoke harness, disconnect things that aren't needed for motor test. I'd even tried just running the motor alone, removed off of the frame.

Mike, after studying the video I can’t help but noticing the wobble of that flywheel like Joe stated....Is there end shaft play on the motor itself? Checking the Pittmans I have on the shelf, there’s no endplay. Did you remove the flywheel for whatever reason? Is it loose? I’m with John, Pittmans are usually very hearty motors, but every once in a blue moon, I’ve seen one poop out....maybe when the jerking happens the tach sensor is physically getting away from the stripe? ......just possible things to look at?........Pat

it looks like to me the motor shaft is moving back and forth and a slight wobble of the flywheel also?!

I think the fly wheel looks to be wobbling because of the tape not applied perfect.  I tried adding a new tape, with no difference noticed.  I did look for excessive shaft movement, and didn’t notice any, but did take a video of it.  Does it look bad?

I can’t tell exactly how much play you have in your motor, but I can tell you the Pittmans I have show zero play back and forth....if you had a second motor laying around, it might be worth a shot, as easy as it is to swap out....can you watch the jerky motion and see if the tape gets away from the sensor? ....it’s the only thing I can think of mechanically that may cause that kind of issue. Is it more prevalent in reverse than forward? Or does it not matter? ......I’d try and rule out all mechanical issues that could be possibilities.........Pat

I replaced the tach reader tonight and no improvements.  The tach tape looks to stay in line with the reader, even with the jerky moves.  

I did notice some slop  in the wheel linkage, not sure if that is normal as I have never had a reason to question it.  

My upgraded premier blue comet from 98 does not seem to be as sloppy, but I have not run it as much as this engine.  I also have only pulled the passenger cars issued with the Dreyfuss which are very light, and wouldn’t think they would cause excess stress on these linkages.

Mike, make sure your eccentric cranks are positioned properly on each side. 

I would also try to remove some of the lateral slop of the flywheel by snapping a "C" clip or two onto the worm gear shaft, inside the gear box, between the worm gear and the inner box wall that the shaft comes through.

I have upgraded plenty of Dreyfuss engine with both 3V and PS-32, and no issue with the Upgrade SF on MTH web.  SO, motor mounts are loose, flywheel loose, maybe motor screws loose.  these are many of the typical issues I find when dealing with a premier engine for a repair.  They are normally taken care of as I do the repair.  Did you change harness and such, or just add the board.  Is anything touching shaft of motor?  Did you take gear assembly cover off?  Do you have the thrust washers and bearings installed correctly for the worm gear?  Things to look at.  G