Sounds like you might be in the market for a new motor and speed sensor. eBay usually has quite a few “good, used OEM” motors (caveat emptor) listed [probably left over from an upgrade] OR you can buy a new replacement motor from a couple of different sources such as Ride-4-Fun or Marlon (frequently on this newsgroup).
Don’t know your long-term objectives for your car but it might be good to get an upgraded motor (i.e. more HP) and see if your controller can be reprogrammed to take advantage of it. Unfortunately a new motor is a pretty hefty outlay.
What about the “High Amps” (82) error code he was getting? Doesn’t that suggest the windings are fried? I suppose you could try the magnet approach but it seems like a long shot on poor odds to me.
Thanks, Bob & Al, your input is greatly appreciated by this novice, who is losing enthusiasm for the Gem experience rapidly.
I tried passing magnets over the surface of the gravel, but I’ll try just metal bar tomorrow. I learned a new thing: put a piece of cardboard down under the car before removing parts…duh.
The edge/lip of the inside of the sensor body seems roughened, and I’m wondering if the broken magnet pieces scoured it and if that could be a problem.
It would be simple to try a new magnet…any idea where to find one (my first web search didn’t)? Or maybe just get the whole sensor assy itself? Best source?
So if I put the (empty) sensor cover back on, power up and try moving the car at this point, unless there is a piece of magnet inside, I shouldn’t do any damage, yes? And if there IS a tiny chunk of magnet in there, I guess I’d find out pretty quickly, yes? Then, new motor.
The motor is a 7 hp from Ride-for-fun, swapped in '08 by the previous owner. How can I be sure the controller was reprogrammed at that time, and if by some chance it had not been, how would that affect the operation?
I shared your discouraging experiences when I first got my 01 GEM last year. I had all sorts of problems last fall and early spring but eventually got it all sorted out (and spent some $$ in the meantime) and all is now working well. I love my GEM, it’s a lot of fun to drive and I drive it every day when it’s above 60 and no rain in the forecast (OK I’m a bit of a wimp):rolleyes:.
If it’s a R4F motor, they typically include reprogramming as part of the package so I’d imagine it was already reprogrammed. If you were getting 30+ MPH I’d be pretty certain it was. If you buy another R4F motor, they’ll include the reprogramming w/ that so you’re covered either way. Marlon also provides assistance and loans the programming control to allow you to reprogram your own motor and he sells motors as well.
Incidentally even if the controller wasn’t reprogrammed at that time (though that makes no sense), it will still work fine. You’ll have a bit more torque on starting up and the top speed would still be 25mph. Other than that it shouldn’t affect the operation.
Just a thought: Though I’m no expert on your 05 model year, I understand that after 04, the controllers were all hard-coded to limit the speed to 25MPH. So people started “tricking” the controller by removing half the magnets on the speed sensor. As a result, the speed sensor told the controller it was traveling at 1/2 the actual RPM. The controller then was happy to let you go twice as fast (twice the design RPMs; possibly a magnet that may have been removed or damaged or reglued; etc). This may have contributed to you sensor failure. Of course it could simply have been rust as Bob mentioned especially since the R4F motors have ventilation holes in the housing.
I think I’d probably call R4F to discuss your options. Maybe they will even sell you a new speed sensor for their motor. Be forewarned Jim can be a bit “rough” to talk to on the phone so don’t take it personally. But he knows his stuff.
Thanks, it’s all helpful information. These things are more complicated than I expected. And yes, calling R4F is at the top of my checklist at this point. I suppose I’ll try moving the Gem first so I have more experimental results to report.
Another perspective on the 82 error: Another blog on GEMs I found recently has suggested that the error code 82 might in fact be simply related to a lack of speed sensor input and not necessarily a motor problem. Their logic was that the controller is calling for power via the foot pedal to be applied but lacking any feedback mechanism from the speed sensor saying it was being applied, the controller keeps increasing the amps being sent to the motor. Continued lack of feedback finally maxes out the controller current limit and it throws the 82 error code and shuts down to protect itself.
Thanks again, Al. Boy, wouldn’t that be good news! Smart controllers!
I reattached the empty sensor cover today and tried moving the Gem, and it starts off trying to go with no error codes, but within a few seconds, in any mode, it shuts down and displays the error code 82. The fact that the motor starts to go, at first with no error code, makes me think it may be ok but is being shut down as you describe, by the conflict between the need for sensor feedback that it doesn’t get.
I’m going to believe your new info is correct and get a new speed sensor, with fingers crossed. Odds of success? Any suggestions on where to get one?
I think the problem you’re going to have is the missing /damaged magnet rather than the speed sensor itself. If you check eBay under “GEM cars”, there are a number of sensors available for sale. BUT if you don’t have the magnets mounted properly, there won’t be anything to sense.
I haven’t taken my motor apart so don’t know how it all fits together mechanically but I’d think the magnets would be mounted on the motor proper and spin as the motor turns. The speed sensor I would expect is simply mounted to the motor and just senses the magnets rotating and THAT is what gets sent to the controller as RPM as part of the necessary feedback so the controller verifies the motor is turning at the requested RPM.
I still think it would be prudent to call R4F and talk to them since it is their motor and they may have some suggestions such as pulling it out and sending to them for repair or rebuild? Maybe as a “core exchange”?
Update on the 82 code error code (with turtle and wrench)–I spoke with Jim at R4F (a fount of information, to say the least!), ordered a new sensor with a couple new magnets, installed easily and the Gem is on the road and running well! I probably didn’t really need the new sensor, but wanted to support R4F (might need him down the road) and expect to be replacing a lot of parts anyway as I try to keep the Gem moving.
My next question is about differential noise–I don’t know what these should sound like, but it seems to me it’s really ‘whiny’ (beyond just motor whine, I suspect) and a little clunky when I take my foot of the accelerator and coast and back again. Any suggestions on how to investigate? Thanks.
VERY GOOD NEWS! So glad you got back on the road and all is well. Yes R4F (Jim) is a bit “crusty” but they do know their stuff.
Depending on the year, the differential was made with either straight cut or spiral cut gearing. I THINK GEM changed this design somewhere around 04 or 05. Straight cut gearing IS noisy and “clunks” when you either start or let off the throttle as it takes up slack with the next gear but much cheaper to machine. The clunk you hear is the gearing engaging/disengaging the teeth in the next gear. Spiral cut is quieter since it has a more gradual face on/off between gears and tends to be “smoother” in operation but is much more expensive to machine. I know because I asked one time about gears when I was doing some consulting work for a company that made gearing for really big mining machines.
I’d maybe check the fluid level in the differential to see if it’s right but if so, I wouldn’t worry about it. My 02 GEM has straight cut gearing and “clunks” pretty loud but all is well.
Thanks, Al. Good to know. I must have the straight cut gears–did Gem change from straight cut to spiral cut around '04/'05 or the other way around? I’ve begun looking but haven’t yet found instructions on checking the fluid level and adding or changing if needed…can you point me at that info?
I noticed eBay has theses parts but they are not OEM…do you think they will work ok? I replaced my broken magnet and problem not fixed. I also replaced OEM speed sensor and I continue to have problems…it only goes about 4’ each time I press accelerator. Wondering if I should try OEM magnet?? Suggestions?