Can't get above 6,000rpm

ssearle · Jan 20, 2011

I've done a laundry list of test to fix this problem with no luck. Here's where I'm stuck now: confirming the injectors and electrical, that tell the injectors to open, are functioning properly.

I had the injectors cleaned and tested. The numbers came back at 512 cc and 524 cc per min. at 20 psi both before and after the sonic cleaning. So bummer that there wasn't an improvement of flow after the cleaning. I can't find the information anywhere as to what these injectors (yellow) are supposed to flow at or if the difference between the two means one is bad or what. The Machine shop that did the test say they both have good spray patterns. GRRRRR!

Also, I'm wondering if there's a way to plug them into the fuel rail and provide power in the system to confirm the electric current is getting to the injectors and opening them fully creating a spray pattern on say a piece of cardboard. Am I loco? I just hate to put this thing back together and have the same issues as when I took it apart, and not fully test everything I can relating to the injectors.

Okay, I'll stop talking... Penny for your thoughts. Thank you for all your help. I wish I had found this site prior to buying the sled. You guys are incredibly nice and helpful.

FatBoyzfrenchy · Jan 20, 2011

Does it back fire?
If it does, investigate the TPS and its harness.

FBF.

guidoxpress · Jan 20, 2011

what have you done o try and fix the problem? List what the symptoms are, and what you have tried besides injectors.

ssearle · Jan 20, 2011

It does backfire, like crazy. Checked and reset tps and looked harness over in detail. Couldn't find anything.

I have another sled that's the exact same sled. I've thought about swapping the harness to try and isolate even more.

Local shop says that it's acting like it's running very lean and thought the injectors weren't delivering enough fuel. That was the only reason I started down the injector path.

I'm happy to try anything. Thank you for your thoughts and ideas. Please let me know if you think I should do more with the harness than what I've done. Maybe swap from other sled???

Thanks again.

guidoxpress · Jan 20, 2011

do you have boondockers control box?

on the TPS harness, you cant tell if its broken inside the insulation. the wires near the harness on the TPS tend to break inside...you can test this by OHM meter and check for continuity on both sides of the wiring harness...and when your testing it, move the wires around to confirm its broken not a short.

you can get the updated harness from Polaris thats $35 or so...or you can do the harness your sled and replace the wires from the black clip for the sensor all the way back to the ECU plug...

the TPS will cause a backfire for sure...ecspecilly a bad harness..

ssearle · Jan 20, 2011

Here's what I've done:
Checked reeds, cleaned/inspected bellows, removed power valve springs and plugged vent hoses, had ecu re-flashed for slp pipes, fuel pressure checked, ignition timing checked, checked boots on intake, had tps checked and re-set, checked stator in and out of sled, checked oil pump and replaced cable, checked over all harness' for damage.

After all that, when I start the sled, it has a hard time idleing. If I feather the throttle it will climb up to 6,000 rpm with a couple intermitent boost to 7,000-7,500 rpm and then levels out at 6,000 rpm no matter where the throttle is. It backfires like crazy. It's like it has a govenor at 6,000 rpm. I've taken it to two shops who have both run whatever test they could and said that the electrical system all checks out perfect and spot on with everything and that they just don't know. One shop thought it was acting like it was running lean and suggested the injector clean.

Thanks for your help.

guidoxpress · Jan 20, 2011

check the TPS harness first and report back.

do you have a boondockers box?

jltbo · Jan 20, 2011

tps

We have replace 3 tps with the same symptom expressed in message and all are running good now

ssearle · Jan 20, 2011

I don't have a boondockers control box. I hate to say it, I don't even know what that is. Should I get one?

I've checked the tps harness for wire damage. I even swapped plugs from my other sled because the wires were corroded where they go into the plug. Is there anything else I should do to check harness?

guidoxpress · Jan 20, 2011

ssearle said:
I don't have a boondockers control box. I hate to say it, I don't even know what that is. Should I get one?

I've checked the tps harness for wire damage. I even swapped plugs from my other sled because the wires were corroded where they go into the plug. Is there anything else I should do to check harness?

lol. no you dont need the boondockers box, if you had one and its not wired right it will cause a bog...

ohm the tps harness...even if they are good...replace it like i stated yourself or buy the updated harness...then move on...dont assume its good just cause it looks fine....same goes for stators...they can test good but infact still be bad..IMO

ssearle · Jan 20, 2011

I'm sorry. I failed to mention: when I try to go into reverse the engine dies but won't start back up in reverse. Just dies. I originally thought tps because of this but dealer thinks it's trying to go into reverse but running to lean and that's why it just dies. I'm not very knowledgable about the tps. Can it test fine but still be bad? Tps set at .918 at 1041 rmp.

I have to run into a meeting, will check back when I get out. Thanks again everyone.

guidoxpress · Jan 20, 2011

oh yeh...TPS or TPS harness...ill bet money on it...

http://www.snowestonline.com/forum/showthread.php?t=67427

http://www.snowestonline.com/forum/showthread.php?t=72725

build your own tps tester and do it yourself..

also do a sweep test of the TPS with the analog style multimeter...you may have a flat spot on your TPS as well.

BIGGDAWG · Jan 20, 2011

ssearle said:
I'm sorry. I failed to mention: when I try to go into reverse the engine dies but won't start back up in reverse. Just dies. I originally thought tps because of this but dealer thinks it's trying to go into reverse but running to lean and that's why it just dies. I'm not very knowledgable about the tps. Can it test fine but still be bad? Tps set at .918 at 1041 rmp.

I have to run into a meeting, will check back when I get out. Thanks again everyone.

that is wrong tps should be at .93-.97 depending on altitude. also have you checked fuel pressure? 05 should be 58 psi and 06 should be 116 psi.

everything you state sounds like tps sensor or low fuel pressure especially if no reverse. i would take the throttle bodies completely off and go through the complete set up procedure and in all reality i would change the tps and harness, i had one bite me in the ars, it was a year and a half old including connector and it went bad and i wouldn't believe it so i pissed with it for many weeks till i decided to change it again..

ssearle · Jan 20, 2011

Thanks, I will go and do as you guys say.

Fuel pressure was checked and was 58 lbs.
I haven't built tps tester and done myself. Before I saw the post on how to do that I had the local shop test it. He said that as he steadily increased the rpm, the voltage also steadily increased to top out at 4.??? (I think, I can't remember the exact number).
I live at about 6500 feet and ride at between 9500-10500 ft elevation.

I will do as you guys say but is there anything else I should do before I put this thing together? Engine is pulled and everything is taken apart so that I could get fuel injectors out.

Sorry for being a pain. Prior to a week ago, I had never done more than replace a belt. This is all invaluable information to me and I appreciate it.

FatBoyzfrenchy · Jan 20, 2011

As Guido says, visual inspection of the TPS harness will tell you nothing. The problem with the factory harness is the wires are breaking inside the insulation right at the pin in the connector. You can pull the wire and connector apart and I bet you the insulation will stretch because there is no connection between the wire and the pin.
Anyhow, it's a cheap and easy fix to a common 900 problem!
Do yourself a favor and replace the TPS connector just on spec.

FBF.

bustamove · Jan 20, 2011

check compression? mine wouldn't idle and back fired.. i broke a piston skirt.

ssearle · Jan 21, 2011

I must have been smoking crack yesterday and in too big of a hurry. I will check ohms on harness wires. I've purchased the stuff to build the tps tester, thank you guidoxpress for that too. I'll need to buy an ohm meter and am going out of town to help with a boyscout campout, may not be able to get back with results until next week but will return and report. I hate it when threads just stop without hearing if the suggestions fixed the problem.

Cylinder compression was 100 on both sides.

ssearle · Jan 29, 2011

Still won't go above 6,000 rpm

Okay,

I've replaced the TPS harness, TPS sensor and set voltage. Idles better and doesn't backfire as much but still won't go into reverse and won't go above 6,000 rpm.

I've also taken the fuel injectors out and had sonic cleaned, replaced coil, stator, fuel filter, cleaned and checked bellows, pulled springs and pluged vent tube on power valves, checked/cleaned reeds, checked intake boots, fuel pressure is 50 lbs, checked all wiring for nicks/grounding, and changed plugs. I'm plum out of ideas.

Anyone have another thought on what it could be?

guidoxpress · Jan 29, 2011

is the TPS sensor and harness new or from the other sled...

what is yoru idle at now, if its too high, it will not even try and go into reverse

was the sled running fine until you got the reflash on the ECU or was there symptoms before you messed with it or rode it last?

and there is NO check engine light whatsoever?

sounds to me like the sled is in "LIMP" mod do to bad sensor or engine malfunction...

ssearle · Jan 29, 2011

The idle is at 1,000 rpm.

I actually purchased the sled from a guy who assured me it ran great but we didn't have snow to do a test ride and when I got there he "couldn't find" his stand to run it up. Haven't been able to get ahold of him since. So it's run like this as long as I've owned the sled.

I've been swapping parts from the other sled and keeping the parts swapped (in case of multiple problems) and then running both sleds to check for a change. So tps sensor and harness are from the other sled.

I also swapped the exhaust sensor and bellows just to double check those. Still nada.

The check engine light does not come on or flash at all. I took the sled to a shop after my first ride, they said there was a check engine code under history for something about the fuel injectors but said when they cleared it and then ran the sled it didn't come back up.

If the DET engages, would a check engine light come up? Could the DET sensor be bad?

Can't get above 6,000rpm

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