need turbo tuners' input

scottbilt95 · Jun 16, 2014

hey guys (and maybe gals?),

i have a turbo issue that i can't seem to figure out. when starting out at the beginning of the ride, there is great throttle response and top end. after a while, it gets sloppy on the bottom (doesn't feel like lag; more like too rich) and starts to spit on the top. feels like the det sensor but no code or over-rev. rpms about 7600 ish when the problem starts. here are the sled details:

2011 800 assault w/1600 miles
-snow X piston kit fix installed @ 1200 miles
-re-built turbo @ 1200 miles
-silber 2012 turbo kit @ 11 psi set up to silber install manual recommendations for 9-10K altitude
-stock injectors
-10% enthanol resistor
-boondocker EBC
-sunoco 110 fuel

i'm a pretty good tuner. this is what i know:

-afr is around 15.0 at idle or cruising and 11.5 WOT. and stays the same when it starts spitting on top so it's not a lean condition
-both plugs look good with no signs of deto
-both jugs have good compression
-thought it may be an exhaust valve issue on the bottom end but if it wasn't closing, the top end shouldn't be effected, same if the reeds are chipping
-tried pulling fuel out on the bottom/mid to clean up the bogging with no results
-clutching is all legit (clean, good belt, primary spring not broken)
-no engine codes

it's something that happens when it gets hot;

-fuel pump?
-injectors?
-stator?
-pipe?

also seems to have gotten worse. hopefully, someone can give me some direction. hate to tear it all down but may have to. any help would be greatly appreciated. hopefully, it's just one thing.

thanks again, jeff

kanedog · Jun 16, 2014

What fuel controller do you have?

RDS88 · Jun 16, 2014

Reeds?

scottbilt95 · Jun 16, 2014

kanedog said:
What fuel controller do you have?

The stock silber unit. I think it's made by dobeck

scottbilt95 · Jun 16, 2014

RDS88 said:
Reeds?

Could be causing the sloppy bottom but I don't think it would hurt the top end. Also if the reeds were chipped, it should be sloppy on the bottom all the time; not just when it gets hot....i would think????

kanedog · Jun 16, 2014

If you only have the 2 stock injectors, they won't be able to provide enough fuel at 11 lbs of boost.
That won't explain the bottom end problems though.
Here is my experience with the Dobeck-like you, it was great when I left the truck, crisp and hauled *** when I held it to the bars on the trail. As the trail went up in altitude, it would start to miss and spit. I could almost have marked a certain tree where it would start acting up. This lead me to believe it had something to do with altitude. I pushed buttons, changed colors, up down sideways and it always ran like crap at higher altitudes.
At the end of the day when I would come down from riding at higher altitudes, it would not miss a beat on the trail as I went by my favourite tree!
I changed my fuel controller and turbo and I haven't had the problem since.
Dobeck and other tune by color fuel controllers just don't have the tuning ability that mountain riders need. Who knows what parameters are programmed in those things?
I only have experience with Boost-it but it's not available in the USA.
The only other choice is Vipec but I have no experience with them.
Bottom line is it's another 2k+ to make your sled run, plus extra injectors, mounting the injectors etc.
I can only suggest to give Turbo Performance a call. They have great knowledge, great customer service and great prices.

J almont · Jun 16, 2014

A little rich

11.5 is definitely not pig rich at WOT, but you have some room to lean it out.
Try 12.2 WOT.

swrev · Jun 17, 2014

Are you maintaining boost? My sled is a carb turbo, but w/ the issues you are having, the first thing I would check is a split pipe. Not sure if the EFI sled will react the same way or not, but I didn't see it listed as something you've checked.

scottbilt95 · Jun 17, 2014

swrev said:
Are you maintaining boost? My sled is a carb turbo, but w/ the issues you are having, the first thing I would check is a split pipe. Not sure if the EFI sled will react the same way or not, but I didn't see it listed as something you've checked.

just checked the pipe.other than the pita of getting the heat shield off, it looks good. maybe it's in the EBC.....may try bypassing it this weekend if there's enough to ride on

capulin overdrive · Jun 17, 2014

Have seen it be fuel pump and/or regulator in other run bad threads, where they mess up when hot?

theshadowrider · Jun 17, 2014

I don't think its the ebc it would not effect tuning. In my experience with problems the majority of heat related problems are usually electrical. I would have to side with kanedog that my first guess would be your fuel controller, then injectors. Those fuel controllers do have quite the history of causing headaches. Do you have a buddy that you could swap controllers to a known working one? Have you checked simple stuff like plugs, wires boots, ect? Maybe you have a spark issue?

scottbilt95 · Jun 18, 2014

theshadowrider said:
I don't think its the ebc it would not effect tuning. In my experience with problems the majority of heat related problems are usually electrical. I would have to side with kanedog that my first guess would be your fuel controller, then injectors. Those fuel controllers do have quite the history of causing headaches. Do you have a buddy that you could swap controllers to a known working one? Have you checked simple stuff like plugs, wires boots, ect? Maybe you have a spark issue?

possibly the controller; have fought them before. i would think the afr #'s would give some indication of a fueling problem????

m1kflyingtiger · Jun 19, 2014

Another thing to check, that's fairly simple to do and rule out, is your tps. Mine did similar things when the tps was on its way out. If you can check it in the garage, then when it starts acting up check it again.

scottbilt95 · Jun 21, 2014

m1kflyingtiger said:
Another thing to check, that's fairly simple to do and rule out, is your tps. Mine did similar things when the tps was on its way out. If you can check it in the garage, then when it starts acting up check it again.

tps makes sense. i will bench test it in a day or so. i also noticed the injector harness had a yellow band around it. does that indicate it is the updated version? polaris online says red was original and is no longer available. yellow indicates the improved version. is that accurate?

thanks again for all the help

m1kflyingtiger · Jun 21, 2014

Yellow is a new version that superseded the old parts. If your putting them in an ecu reflash is required. When you do the tps checks make sure to put it through its paces and check it multiple times. When my last one went out it would set, then not return to the setting, then after awhile it would just move voltage on its own. I strongly reccomend takin your tester on the next ride as well as bech checking it and if the issue comes up, check it then and there.

scottbilt95 · Jul 5, 2014

update

have checked these items so far:

-pistons
-exhaust valves
-reeds
-pipe
-injectors (already had the updated yellow coding)
-boost lines
-bov
-boost actuator
-turbo

next will check the map, throttle position, and engine temp sensors. if these check out, i will get the fuel controller checked.

jeff

scottbilt95 · Aug 19, 2014

the verdict is in

Fuel controller was bad. Would work when cold but as it warmed up it would start having voltage irregularities. Thanks for the help dobeck! Also, fyi the stock t stat flows ridiculously slow. Apparently there are some better options. Anyone ever heard this?

Thanks again.

Kenny B · Aug 20, 2014

I have a thermostat kit on my Assault, I dropped a full 20 degrees F on my assualt, and it is much more stable, a number of company's have kits out there, I just got mine from Terra Alps with the head kit. I installed both at the same time, but it definitely does a better job of regulating flow. I'm sure a better head design did wonders for heat to. I feel it was 280 well spent. Also get some redline water wetter in the sled. That stuff is da bomb.

Lucas also makes a additive, not sure how it works but redline works good. I have it in all my rides. ( Cars, Trucks, SideXside, etc...)

doudea · Sep 27, 2014

Had a similar symptoms on my 2011 turbo pro. Tried every thing I could think of, and finally got a tip on SW to try the new Polaris pick up valves in the tank.

2011 they had problems with the pick up valves in the fuel tank. It shows up way more on the turbos because they are pulling more fuel than stock. One of the one way valves starts allowing air to pull into the fuel system once the tank gets lower on fuel level.

Polaris has a new updated pick up assembly that solved my problem, after almost a whole season down the tubes with trouble shooting. Look at a 2011 parts list and they have a new part number for the pick up assembly.

need turbo tuners' input

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