Sha35297

Damn, didn't see there were several more comments before I responded. So ignore my previous post. I know you have said you checked timing over and over, but it really sounds like either timing or valve adjustment. 200psi compression is very high for that machine. Especially being that it has automatic decompression. Should be closer to 80-90. Could be as low as 55 and still run good. 200psi is way too much, indicating incorrect valve lash or bad timing adjustment.

Another common issue with these model bikes is the camshaft. I have had a couple in the shop that would idle great, but die as soon as any throttle was pushed. The exhaust lobe on the cam was worn down to almost perfectly round. Just enough to allow it to idle. This one could maybe be beyond that point. Grasping for straws at this point. I'm sure you may have said you did this, but check the intake boot between the carb and engine for cracks. Spray some brake cleaner on it while its running and see if it revs up rpms or floods it out.

Are you certain that it is valve chatter and not piston slap?

I had this exact same problem on a grizzly 700 just the other day. I'm not familiar with how the starter solenoid works on this particular bike, but the way it works on the grizzly is when the ignition is turn on it supplies power though the starter solenoid which then powers everything else. On the grizzly the power would send to everything while holding the starter button down and then would kill power as soon as the button was released which would cause the bike to kill every time. May be a long shot. One thing I do know from an older Polaris I worked on years ago was that the ignition switch and the power switch on the handlebar are directly linked together and can cause running issues. The other thing with the older bikes is the switch inside of the throttle mechanism on the handlebars. It has to be functioning and adjusted properly. Hopefully this helps.

Final update on this issue. The shift pin in my previous post was not the issue in this case. After replacing every electronic component on the ATV with no change with the problem. I had to pull the engine back off completely and go through everything with a fine tooth comb. Finally I found an issue that is not mentioned anywhere in the manual, on the internet that I can fine, NOWHERE. Inside the main shaft that the dual clutch goes on there is a brass or copper ring that the feed pipe "A" stabs into. In my case that brass/copper ring was scarred up. Apparently causing a variation in the oil pressure that the computer sensed and made it now allow the bike to down shift. It never threw an actual code. The MIL light comes on steady and does not allow the bike to shift at all. I installed a new mainshaft and now the bike shifts great. I hope this helps anyone who has this issue.

Update, I read on another forum that these bikes are prone to having the, Gearshift Return Spring Pin, break off. So I drained fluids and removed the font crank case cover to put my eyes on that pin. It was not broken and was doing its job. so I reassembled everything. Added fluids and tested again. Same issue as before. I also cleaned the idle air control valve, TPS, and speed sensors. I pulled every electrical plug and cleaned them with electrical cleaner and blew them out. Nothing has made any changes in the behavior. I notice that if I downshift manually in ESP mode while still slightly holding the throttle it will sometimes work better. Never in Automatic mode though. So I may replace the TPS to see if it will resolve the issue. Still no trouble codes either.

Gwbarm, Yes I know what the MIL light is. That is why I stated that it is not blinking to indicate a code. It is just staying on solid and there are no codes stored in the ECM. I am a mechanic who works on these daily. I have followed all of the troubleshooting tips in the service manual with no help. Just trying to see if anyone has had this issue before or maybe could steer me in a direction that I may be over looking. Thanks.

I have this bike in my shop for a customer. It was sunk completely under water and left running until it killed. I did a complete engine rebuild. Replaced all bearings, crank, oil pump, and various other components. Engine starts and runs great. It will shift up through all gears perfectly in automatic and in ESP, but when slowing down it gets to 3rd gear and the MIL "-" light comes on and stays on. No flashes or anything and it will not shift gears. Kill the engine and restart in ESP mode and it is able to shift to neutral and start over. Does the same thing while down shifting in ESP mode. I replaced shift angle sensor with no improvement. Checked oil pressures as per repair manual "74psi" and higher with higher RPM's. With no MIL codes to point at an issue. I am at a loss as to what else to check or replace. Has anyone else ran across this issue?

Yeah, I asked around here locally and no one had the same bike for me to do the swap with. That would have been ideal. On the more common models that I work on, I have a spare ECU that I can do a quick test and see if that is the issue. This bike wasn't something I see around here very often. I picked up a tote full of ECU's and other misc. electronics from a shop that was closing down. Got that and several other useful items for a good price.

Just wanted to give a final update on this bike. Nothing I tried solved the issue. Leads me to believe that the only other problem could be the ECU module or the EPS module. The customer did not want to spend the $800+/- to test the theory. I really hate unsolved mystery, but I gave it my all. Sorry I couldn't come back with a positive update.

I’m not sure where to look to find the starter feed you are talking about. I’m not seeing it in the manual. It’s a 2010 Grizzly 700 FI EPS 4WD. I have a 2004 Grizzly 660 in my shop as well. I tested the pick up coil on it. There is no continuity between the frame and either wire on this one. Which leads me to believe that is most likely my problem. It just isn’t faulted bad enough to prevent the bike from running once it’s started. Also, makes sense that it gets worse once it’s warmed up. It will fail completely soon if not replaced. Thank you for all of your input. It’s nice to be able to bounce ideas to other people and get feedback. I enjoy a good challenge. It is very satisfying once it’s solved. I will update with any new info.

Ok, So wiring it testing good to TPS and Speed Sensor. I did some more testing on sensors and found that the speed sensor is out of spec. Which is most likely the issue with EPS. However, I still do not see anything anywhere that says this would cause the hard start issue. I even unplugged the sensor completely and started it. I acts the same way. So I moved on to the pick up coil. The manual says it should have 459-561 OHMs. I'm getting 601 OHMs. Also, should there be continuity between either of the pick up coil wires and ground? I'm getting 10-12K OHMs there. The manual does not specify this test, but I believe there should not be any contact to ground on that coil. This may be the whole issue.

Ok, Update on this problem. I have cleaned the IAC, it was perfectly clean to begin with. Started the bike with it out and watched it function. Seems to be working as designed. I replaced the TPS, I did a test on the OHM reading while rotating it from open to closed. I used a meter with a graph. The signal would spike up and back down at one point in both directions. Everything else tested good. With the new TPS I have been able to get the idle to calm down a little. However, it sill has the hard start periodically. It is a strange issue, the majority of the time, it will start just fine. When it does decide to act up, it will pop and just sound horrible, but once it starts, it runs great. As far as the EPS codes, yes they are only for that module. It stores its own codes separate from the ECM. I've read that the speed sensor will cause these issues as well, but it passes every test in the book perfectly. I'm going to do OHM tests on every wire in that part of the system and see of anything seems out of wack. Seems like it has to be a wiring issue maybe. The issue is so random though. It will do it on cold starts sometimes, but mostly after warmed up. The throttle cable is adjusted with about 1/8" of free play as well. Diag reading on the TPS is between 15-20. For some reason I still keep wanting to say valve adjustment, but I have already checked them twice. Unless my manual is giving me the wrong specs.... Battery is brand new, starter does not dragging or straining at all. When it has the issue, it sounds just like the timing would be off or valves would be out of adjustment. Sometimes backfiring in the exhaust. I will update with any findings in the wiring system. If nothing is found there, I will have to think that it is the EPS issue causing everything. Which is not a good problem. The module is about $800. I wish I had a spare to plug in and try. I don't know anyone with the same bike anywhere near me.