My Pro Is Still Sick. :(

[SpeedWobble]

So a little over a month ago my Pro started running poorly. Sled would run fine untill you gave it wide open throttle, then it would bog out. This condition would improve as I gained elevation, at 6 or 7 thousand feet the problem was barely noticeable (but still there).

We have changed the fuel filter, cleaned and checked the operation of the exhaust valves, checked throttle free play, changed the throttle overide switch in the throttle flipper, changed plugs (twice).

Dealer and Polaris diagnosed the problem as electrical last week so they changed out the stator plate, voltage regulator (the one on the clutch cover and the booster up by the coils). Still no change. If anything the sled ran worse by the end of the ride. I had to constantly give it gas to keep it running, it would die on me anytime I was coasting down a hill unless I gave it gas.

Its heading back to the dealer this morning, but we are both running out of ideas as to what might be wrong. I'd really like to get this sorted out before I put it away for the summer, and snow is getting hard to get to (I need snow. because the sled runs fine on the stand, with no load on the motor). Every time we think it is fixed, put it on the snow and the problem is still there.

I'm open to any ideas you guys might have!

Thanks!

 

[towngrunt]

Is it bogging out or just running on one cylinder? I know there has been problems with the injectors, mine included. Mine started running on one cylinder in a deep canyon which meant the only way out was on 2 cylinders. No way of towing out so I attempted to side hill out. I was Goofy footing it across a long side hill when the other cylinder decided to kick in and you can only imagine what the picture looked like for about 5 seconds. Any ways my dealer discovered bad injectors. This was about 300 or so miles ago and sled runs great. I feel for you nothing more frustrating than not having a cut and dried solution to the problem. Come to Utah and you can test your sled for another month or so.

 

[IQ?]

Check injector harness.
pto cable rubs where its strapped to other components.
change harness.
Ed

 

[Reg2view]

The PTO lead will rub where it's routed under the MAG side rail mount, and with the 8's vibration, it will rub through all the sheathing, start to fracture one or both of the two wires leading to the PTO injector if it doesn't short it first. EVERYONE should check their leads while it's still under warranty - if it's routed under, it will eventually stall the PTO injector. I believe you can't replace the harness piece alone (from the 4 pin connector to the main harness that splits PTO and MAG wire pairs to injectors themselves), injectors must be replaced with the harness - at least - poo doesn't offer the harness split as a part number without the injectors. I looked. FWIW.

 

[SpeedWobble]

Thanks for the help you guys! I'm curious though, the service tech says the injectors are showing normal operation on the Digital Wrench. Could this still be the problem if there is nothing abnormal showing on the techs computer?

The tech is off today, so I will have to wait till tomorrow to start with new ideas.

I did notice that the digital display would die last week, and periodically the sled would die and not restart for a few minutes. These problems seemed to clear up with the new electrical components they installed before my last ride.

The new problem that showed up is that the clutches would occasionally not upshift. If I was going down hill you would get the engine braking sensation and you had to give the sled a ton of throttle to get it to upshift out of that. I'm wondering now if I don't have a broken motor mount thats causing a bunch of clutch/belt heat. Just more stuff to look at.

I'll keep you posted.

 

[dmkhnr]

How about a chipped reed, this could cause flooding up top, or low/mid.

 

[milehighassassin]

check your injectors for sure, have you done a compression test?

 

[NM]

I vote fuel pump. My turbo pro will bog and screw around at wide open running factory fuel pressure, but if I turn the fuel pressure down to 50 lbs and increase the duty cycle of my extra injectors, then it runs perfect.

I installed a adjustable fuel pressure regulator for testing purposes, and when boost came up and increased the pressure it would bog. I unhooked the boost line so the reg stays at 50 lbs and just adjusted my fuel controller for top end fueling. Sled runs perfect now.

 

[AKSNOWRIDER]

I think Neil is on it..fuel pump is weak.....put a guage on it and check pressures and volume............

 

[SpeedWobble]

Thanks again guys! I am willing to try new injectors and a new fuel pump. The problem is that the digital wrench shows that the pump and injectors are operating within normal parameters, so the dealer and Polaris don't think this is the problem. I'm still trying to get everything covered by warranty so I need to convince Polaris that these swap outs make sense.

Gonna talk to the service tech again this morning, and we'll check and see what codes show up on the diagnostics.

I'll let you know.

 

[chunkysoup]

anyone checked the tps???

 

[black swan]

anyone checked the tps???

mine would cut-out at clutch engagement and wide-open....low to mid range was fine....and the engine light would come on when it happened.

The tps was out-of-adjustment and needed aligned by dealer to fix.
After that, it hasn't missed a beat ever.

 

[NapaMatt]

I would check Fuel pump Pressure and Volume..

also Tighten up any slack in throttle cable..

 

[NM]

Just one other note on the fuel pump. On a long wot pull, the fuel pressure gauge would creep up close to 60 lbs, then drop to 30 when the pump gave up. It would do this over and over until I turned it down.

So just to test the pump at idle in my shop, I would turn the pressure up to just over 60, and guess what...falls to around 30 for a few seconds before trying to recover. In my opinion, the pump is barely adequate for a stock sled, let alone a turboed sled. I rode with a stocker this season, and his sled would cut out once in a while at wide open. The stock fp is 61 lbs.

If I leave the pressure around 50 PSI then the sled runs flawless because the pump is not working so hard. I can make up for the lack of pressure by increasing duty cycle on the extra injectors.

 

[hypnotoad]

Still no change. If anything the sled ran worse by the end of the ride. I had to constantly give it gas to keep it running, it would die on me anytime I was coasting down a hill unless I gave it gas.

I had pretty much the exact same thing happen to mine a couple weeks ago, not the WOT issue but the dying with out throttle. My sled wouldn't idle with out giving it throttle, it turned out to be a TPS issue. Dealer ended up completely swapping out my throttle block to fix it.

 

[SpeedWobble]

So, dealer tech called me today. He found a bared wire that powers the tailight going down past steering post. He said it was shorting out any time he moved the wire. After he fixed that problem he ran the diagnostics with the digital wrench. It showed that the exhaust valves were not activating on every pull of the throttle. He said he would take it to wide open throttle over and over and it was like the 4th time he did it when the valves opened. He had another Pro at the dealership (demo), so he swapped out the ECU and my sled ran flawlessly on the stand. Valves opened every pull of the throttle and would rev right up to 8300.
Gonna take it back out on the snow with the borrowed ECU tomorrow. hopefully the problem is solved.
Thanks for all your replys, I'll let you know!

 

[Kraven]

PLUG THE EXHAUST VALVES

So, dealer tech called me today. He found a bared wire that powers the tailight going down past steering post. He said it was shorting out any time he moved the wire. After he fixed that problem he ran the diagnostics with the digital wrench. It showed that the exhaust valves were not activating on every pull of the throttle. He said he would take it to wide open throttle over and over and it was like the 4th time he did it when the valves opened. He had another Pro at the dealership (demo), so he swapped out the ECU and my sled ran flawlessly on the stand. Valves opened every pull of the throttle and would rev right up to 8300.
Gonna take it back out on the snow with the borrowed ECU tomorrow. hopefully the problem is solved.
Thanks for all your replys, I'll let you know!

In about 2 minutes out on the snow, you can simply eliminate the intermittent exhaust valve solenoid problem by bring a 2" long 5/16" diameter stud (take a 2" long bolt with a 1/2" socket head on it and cut the head off) and plug the hoses coming off the exhaust valves.

Once you run it this way, you'll want to run them "plugged" all the time. There's other threads on here with positive results by doing this.

If you desire a quicker more temporary test/fix, take a pair of mini-vice-grips and pinch the rubber hose between the "T" and the solenoid, and take it for a test run

Hope this helps

 

[Hawkster]

Better yet get some rubber plugs for carbs and etc. from an auto store and zip tie them on the nipples of the valves , nice clean look and the heat hasn't bothered them so far.

 

[Kraven]

MONTE's HI-TEK EXHAUST VALVE PLUG KIT

Better yet get some rubber plugs for carbs and etc. from an auto store and zip tie them on the nipples of the valves , nice clean look and the heat hasn't bothered them so far.

Better yet, contact "the Full Monte" here on SnoWest.

He offers a kit where he removes the pressed in fittings from the exhaust valve bodies, threads them to 1/8" pipe thread, installs aircraft quality super-blue anodized aluminum recessed allen head plugs, along with some FAA approved teflon tape for that perfect seal and picture perfect appearance .....................................................

And if you ever wanted to return it to stock, just remove the plugs and replace them with brass 1/8" pipe to 1/4" slip-on barb fittings.

 

[Hawkster]

Nice , someone always makes a better wheel