No reverse. 2014 RMK Assault

[SnowBaller]

Stock 2014 RMK Assault

Sled will not go into reverse. When the push button switch is engaged the engine will start to die, like it's supposed to, but then rev up back to normal idle. I have tried a new switch, both the new and original ohm'd out just fine. I also have a service manual so I was able to reference the electrical diagram and get an ohm reading from the switch connection under the hood to the ECU connection, and switch connection to ground, both check out fine.

I'm not an electrical guru so any help, tips, or tricks, are appreciated.

 

[SRXSRULE]

TPS sensor needs adjusted. Pretty common symptom. Eric

 

[Sheetmetalfab]

TPS sensor needs adjusted. Pretty common symptom. Eric

^^^^ what he said

 

[SnowBaller]

Thanks for the replies, guys. I'll check that out.

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[Caper]

It's also a sign of low compression. Might wanna check that!

 

[diamonddave]

Believe it or not, but I have now fixed 2 sleds with this same problem with new spark plugs.

 

[fuledya]

Check compression

 

[The Bob]

I was having some on and off the throttle DET problems and decided to look at the TPS again (just assembled sled earlier this year). I checked the base and moved it a bit, but it wasn't out of spec, ended up with it at .705. Then adjusted my idle volts to the higher end of what Polaris recommends (9.3-9.5). I got it right at about 9.5 (9.48) and put it back together. My reverse was gone, button did nothing, like it was broke. Anyway after checking all connections, jumping the switch, etc., I re-adjusted the idle tps (doubled checked the base to make sure it didn't move) to 9.38-9.4 and bam reverse was back. PITA.

I was using PCV and a Fluke to test.

 

[SnowBaller]

Sled has around 400-500 miles.


Changed to new spark plugs, no change.

Checked compression: PTO 105psi, MAG 102psi. Engine was only slightly warm from running it earlier to check if new plugs would work. Compression seems low. What range should it be?

Also compared to 2014 800 RMK (around 600 miles)with working reverse; PTO 110-112psi, MAG 110-112psi. Cold engine.

Any other ideas besides the TPS? What can be done to address the low compression?

 

[The Bob]

Did reverse ever work for you? Is the sled new to you?

 

[SnowBaller]

The reverse worked last season, but only had one trip to Montana with it. The two trips I've had this year the sled has ran fine except for no reverse.

I bought the sled in May of 2014. It was a private sale but the sled only had 0.3 miles. It sat the whole winter of 2013-2014 and was never ridden, still had all the tags and stickers from the factory when I picked it up.

 

[diamonddave]

Make sure your throttle cable doesn't have excessive slack. The flipper has to be able to return to full zero in order for the TSS to allow reverse.

2nd) I would replace the fuel filter and verify the TPS.

 

[Carlos Randolph]

Compression

Those compression numbers are pretty low....as in not very good at all on a good reliable tester. Remove an exhaust valve and look down in there to check for scuffing of the pistons or flaking of the rings.

Find a differnt comp tester or buy one just to rule out a bad tester/guage....just handy to have. COLD motor: pull the plugs, clamp the throttle WFO, pull over 5-10 times til the guage reads the highest number. Do both sides in this manner. Then do it to the motor hot or warmed up, checking in the same manner.

I would be concerned about any number bellow 110psi on a cold or warm motor. Some motors might run fine other wise, but don't have enough pop left to pop over to runnng in reverse.

@2cents

 

[SnowBaller]

Those compression numbers are pretty low....as in not very good at all on a good reliable tester. Remove an exhaust valve and look down in there to check for scuffing of the pistons or flaking of the rings.

Find a differnt comp tester or buy one just to rule out a bad tester/guage....just handy to have. COLD motor: pull the plugs, clamp the throttle WFO, pull over 5-10 times til the guage reads the highest number. Do both sides in this manner. Then do it to the motor hot or warmed up, checking in the same manner.

I would be concerned about any number bellow 110psi on a cold or warm motor. Some motors might run fine other wise, but don't have enough pop left to pop over to runnng in reverse.

@2cents

I tested each sled twice in a very similar manner as you have described. However, both were cold engines.

Next on the list of things to try are;
1. Check throttle cable.
2. Check compression with warm engine
3. Check compression with another tester.
4. Check pistons and rings.

 

[Carlos Randolph]

Well if it only has 100-105 psi I don't think you need to look at anything else. Motor is on its way down.

 

[Rain Man]

Figure it out yet? If not check the crank sensor. We had a Pro that would run fine but not go into reverse. After looking at all electrical, connections, etc. turned out to be a bent crank sensor.

 

[Popik]

i second the crank sensor solution. I rode two days after my recoil rope broke and ended up in the housing. I lost reverse at the end of the second day. when i finally took the recoil apart to install a new rope the whole flywheel area was bunged up wth fuzz from the rope. Both the crank sensors were tweaked a bit causing a bad reading.

The manual calls for 20 thousandths clearance. Can be set by prying it against a 12 thousandths feeler.

GL

 

[SnowBaller]

I haven't had a chance to work on the sled lately. With my riding season over its not at the top of my to-do list. Hopefully in the next couple weeks I can get to it. I will give an update when I have more to share.

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[SnowBaller]

Finally was able to work on the sled.

Seems it was the TPS out of adjustment. Using a wiring harness built by a fellow SnoWest'er I was able to reset the TPS. The sled now goes in and out of reverse as normal. Although now it has a high idle, 2400-2600 RPM. I should be able to bring that down to under 2000.

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[newbb]

How did you turn your idle down? Is there a idle adjust screw on these sleds? Mine idles around 2500 rpm and I have no reverse either. Hit reverse button and it doesn't do anything. Thinking idle might be to high.