Sounds good. Sled is currently reflashed and sitting in the driveway. Got a little girls 1st birthday party tomorrow so doubt I’ll get away for an hour or two to check it out but we’ll see. Sunday at the latest.
850 RPM hangs
- Thread starter FlatLand_J
- Start date
Leak down test
Before anyone does a reflash, you should first do a cylinder leak down test.
Motor Performance before the reflash...... And performance results after reflash are worthless without leak down numbers.
The big problem with reflashes is...... ( we do NOT know the leak down % on the sled Polaris is using for the mapping ).
Are they using a brand new motor ? With 3-1/2% leak down?
Are they using a 500 mile motor ? With 1-1/2% leak down that had a great cylinder finish and rings sealed up nice ?
Are they using a 500 mile motor ? With 7% leak down that has rings that are on their way out the door...... ( basicly junk )
You see if we knew everyone's numbers...... Then we could see who's sleds the reflash works on and if there is a correlation to the leak down numbers.
And there will be........
If you build a map on a sub-par motor the map is basicly worthless to everyone except another guy with the same sub-par motor with the exact same leak down.
If you build a map on a broke in motor with 1-1/2% leak down...... The Map will be awesome for everyone with a good solid top-end with good % numbers.
As I have said...... All the different results are worthless to the masses without leak down numbers
Dan
Before anyone does a reflash, you should first do a cylinder leak down test.
Motor Performance before the reflash...... And performance results after reflash are worthless without leak down numbers.
The big problem with reflashes is...... ( we do NOT know the leak down % on the sled Polaris is using for the mapping ).
Are they using a brand new motor ? With 3-1/2% leak down?
Are they using a 500 mile motor ? With 1-1/2% leak down that had a great cylinder finish and rings sealed up nice ?
Are they using a 500 mile motor ? With 7% leak down that has rings that are on their way out the door...... ( basicly junk )
You see if we knew everyone's numbers...... Then we could see who's sleds the reflash works on and if there is a correlation to the leak down numbers.
And there will be........
If you build a map on a sub-par motor the map is basicly worthless to everyone except another guy with the same sub-par motor with the exact same leak down.
If you build a map on a broke in motor with 1-1/2% leak down...... The Map will be awesome for everyone with a good solid top-end with good % numbers.
As I have said...... All the different results are worthless to the masses without leak down numbers
Dan
Last edited:
So after a few hours on the new map (awesome btw) rpm hang is still there. Looks like the next step is lube up the cable.
M1K
Maybe stupid question, but after the reflash, is the hang related to snow packing in the throttle and becoming ice? I still get this from time to time but normal IMO.
When I first encountered hang, I tested it by driving out of the garage onto a completely groomed trail. In the absence of snow dust and having it happen told me it was initially computer related and the flash seems to have fixed... or at least reduced... it.
It might die down as the engine ages too.
OTM
Last edited:
I don’t think snow pack, as none of my other sleds have done it and I haven’t changed the way I ride from sled to sled nor has polaris changed the throttle block. But I am leaning towards maybe some moisture in the cable. It seems to do it more the longer it’s outside. The first time I noticed it was riding back from work, which we rode there and it sat outside for 12 hours. Yesterday it didn’t hardly do it at all (maybe once or twice) on the ride out. But consistently and repeatable on the ride back. This is the direction I was leaning from the start but like to do one change at a time and ensure I know what the problem and fix is.
J
In lighter snow I fight with the throttle as the day goes on. Handwarmers make it worse. It seems once you get some heat and/or moisture in to the cable you are done. Going to try getting some silicone lube all throughout the throttle and cable. Not sure if this is the sole contributor of this, but definitely an issue for me on all Polaris throttles.
T
trdehmer
Member
I noticed On a trip a bit, not saying it’s worse after reflash (which I got last week), but I get “idle load up” so after riding somewhat aggressive then getting to some slower twisties the sled will drive itself with no thumb on throttle. Takes 100-300 feet or so for it to idle down, or if I slam on the brake. Sucks coming to a stop sign! When mine hangs, it’s at 5000-5500 RPMs.
Last edited:
My boosted sled seems to hang from 4500-5000 and agreed it seems worse as the day progresses AND when riding aggressively and then slowing it down for any reason.
Sounds like exactly what mine does.
I've reported this issue to my dealer. Service manager thinks it has to do with the throttle plates having a hole drilled in them to help with idling. That when you let off the throttle it's now pushing more air into the engine than the 800's did and that's what we are noticing.
Got another ride in after lubing the throttle cable. Still definitely hangs.
T
trdehmer
Member
If your idle hangs on your 850, have your dealer check your fuel pressure at idle via digital wrench. Supposed to be around 58psi per Polaris. Supposedly a new fuel pump has helped the issue for some as their fuel pressure at idle was in the 60-65psi range at idle which I believe would make it too rich throughout the RPM range.
Question is, is it a too lean or too rich condition that is causing the "idle hang/ghost riding" issue.
Question is, is it a too lean or too rich condition that is causing the "idle hang/ghost riding" issue.
"The fuel system also gets new sensors via a fuel pressure sensor and a fuel temperature sensor"
They add these sensors to know the fuel pressure and temp but do nothing with the data? Maybe it is an option for them to use in future firmware versions...
Is the fuel pressure sensor in pump package? Maybe the sensor is faulty in these ones that are showing 60-65psi. This could throw the mapping off.
They add these sensors to know the fuel pressure and temp but do nothing with the data? Maybe it is an option for them to use in future firmware versions...
Is the fuel pressure sensor in pump package? Maybe the sensor is faulty in these ones that are showing 60-65psi. This could throw the mapping off.
Last edited:
T
trdehmer
Member
Great question...! I don't see anything in the microfiche that would suggest the fuel pressure sensor and fuel temperature sensor are separate sensors not tied to the fuel pump assembly?
"Industry-exclusive, patent-pending fuel system temp and pressure sensor optimizes piston durability, increases control of fueling variability, improves starting in all conditions, improves diagnostic functionality for easier serviceability, and enhances engine protection modes in the case of low fuel pressure"
"Industry-exclusive, patent-pending fuel system temp and pressure sensor optimizes piston durability, increases control of fueling variability, improves starting in all conditions, improves diagnostic functionality for easier serviceability, and enhances engine protection modes in the case of low fuel pressure"
Last edited:
N
no_uh
Well-known member
This is an issue I've experienced as well, particularly on trails. I'd think this has to be a warranty issue for Polaris, particularly for safety reasons. Imagine if you had any other vehicle, like a car, that continued to throttle after you let off... Luckily everyone who is on here is a good enough rider to compensate in the meantime.
T
trdehmer
Member
T
trdehmer
Member
That’s why I don’t think it’s clutching related at all. Something in the mapping and different tolerances on components from one sled to the next.
Similar threads
