Infamous det code on decel?

Scott said:

Have you checked the pipe sensors?

Have you checked the torque on the det sensor where it goes into the head? REALLY easy to over-tighten them. Just a smudge more than finger tight. I think it's 10 ft/lbs.

Click to expand...

The pipe sensor I swapped from my spare polaris, and I read the sensor is there that it would make the sled richened up if it got too hot?

Knock sensor is for sure not over tightened, I went a smidgen past snug.

The sleds going lean outside of boost, and I should of taken a better notice to that, I'm thinking now she may very well be detonating in and out of the throttle if the factory efi is lean and having issues....

When I took off from the truck today and it ran~14-15:1 cruising for the first way down the trail, I did a ton of ditch banging and lots of on off the throttle and hitting it hard. Not one det code. Then higher elevation and the sleds Fuel injection went way lean it's throwing the code.

Scott said:

Thinking they have two fuel maps bolt into their ECU.
One for low elevation and one for high elevation.

Click to expand...

Yeah that would make sense on 2 maps however it shouldn't switch so drastically and terribly, that's the beauty with modern day fuel injection, runs good at nearly any elevation and temperature. I've been riding the same area and noticed the fueling has been getting worse and worse. It could be a failing stock baro sensor? She's certainly melt down lean. I put in a new o2 sensor last ride, and my now "spare" o2 sensor had 2 rides on it, just wanted to make sure that it wasn't somehow reading wrong.

Scott said:

The sensor on the air box.

Yeah. That might be worth checking.

Click to expand...

I got reading more into tps's and such and with these sleds having a known issue with them I ordered a new one. I had put a used one on my sled and good odds are that it's gone as well. To a degree you can tweak the stock efi fueling as well by how much you turn it. I know there's the adjusting procedure but if it was clocked more the one way that it always thought you are giving it a bit more throttle, it'll run richer. I'm feeling it's a good solid item. Will report back when I know.

Got out, I have something going on with, my a/f now. Last ride was the first ride with, a new o2 sensor. The Bosch lsu 4.9. And when the sled ran lean its probable coincidence to that and the sled throwing the det code. Sensor must of failed all within 15 km...


So today I went out with a new tps, hitting the throttle seemed better, but the a/f either read pegged rich at 10:1 when I left the parking lot, or it read out of range 18:1+. Ran good for a ways again then threw a det code... I then opted to make the threshold on my box from. 8" to 6", for a good while it never threw the det code at all. It was knee to waste deep at spots breaking trail uphill, constantly in boost and on off The throttle, it. Never missed a beat!, earlier I'm the season under the same kinda situation it was throwing the det code very often!

Then I hit the trail heading back down, it threw it once or twice but by then my Intake was getting iced up.

I have no idea where to go from here, I'm banging my head against the wall now. Good odds that my o2 sensor was bad from the get go? Or maybe the aem gauge is having issues somehow? Hmm. At least it ran, good under the harsher trail breaking today.

Went for a ride today, new 02 location, o2 sensor read good all day. I Took my knock sensor off, probably bad timing as I'm sure I gave it some true detonation. I had a few times where the sled "fell on its face" I was watching the a/f and in those times it had zoomed off lean, Keep in mind previously my sled ran fine wide open, I could do a long pull having it pinned wide open and higher boost levels fine, it was in and out of the throttle.

Then after that A few times i noticed in boost while the fueling was OK, it had this weird stutter/bog, and I noticed when it did that, the af started to play around 12:1 then dart up for 1 split reading at 14:1..... hmm....

coming home the sled got worse when hitting the throttle and such,

So now I'm thinking, if I'm going lean in boost I'm not receiving fuel. Maybe my fuel pressure regulator? Probable fuel pump? It has a brand new fuel filter, Same model I've used before and never had an issue, It's over sized compared to stock ones. So I figure well, I may as well order up a fuel pump, Maybe I'll swap my fuel pressure regulator with a spare one I have off my yamaha I had (same one they use). I will check fuel pump FLOW and pressure as well but it seems from the past perhaps an intermittent problem as well.... so who knows,

What a head ache this sleds been for me :bowl:

Finally have the sled sorted, first the o2 sensor failures (ugh) then a recent Issue a spark plug cap I replaced wore out.... Probable cause to my weird miss and leaning out like symptoms wide open, somebody had commented on another post that the a/f will read lean with unburnt fuel as it will not read the unburnt fuel into the reading, just air thus it reads lean.

I discovered why the sled was leaning out down the trail under lighter throttle conditions, as well as the issue with the det code being set off. Boost-It's mapping they recommended really didn't work well, The sled had no gauges when I bought it, it would of been doomed to melt down on the trail I'm sure,There's youtube videos of them on the sled throwing it into the det limp mode as well when climbing a chute and playing the throttle...., If you're wide open and pinned it was ok, but beyond that, not so much.

The leaning up down the trail was because there is the point where you're lightly cruising and the turbo spins up just enough that it is making some pressure and moving a bit more into the engine even at ~10% throttle. enough to lean out the sled when the boost injectors havent kicked in yet.... So the fuel box was not fueling for it with what boost it recommended. sled was leaning way out to 18:1+, I tried a few different set points for their "baro" setting which somehow uses its built in baro sensor and map sensor to figure when to add fuel?, didn't work for me! I now opted to make it run the "old fashioned way" and read only off its internal map sensor, doing so It now fuels for that slight bit of added air down the trail! Thats one problem solved. However i have found to a degree the fuel trim on the lower rpm's will affect my spooling because it then wants to run rich when I'm giving it. (no different than how boost it had it anyways).

Next since I took my knock sensor off I have no "safety" I noticed that the odd time in and out of boost it did go lean still and have some hesitation going back on the throttle, odd time I heard a softer pop. I turned on the fuel box's "accelerator pump" and that seems to have taken away that lean spot in and out of the throttle now, It got to be worse when the boost went up, It needed more fuel as the turbo was wound right out and ready to go!.

It seemed like I had 2 or 3 issues going on almost at the same time so it just was not too easy to just sort or tune.....I can only hope it treats me well now for what's left of the season (not much) spring sure is in the air now and snows been melting a bit up high.

I appreciate everybody's input on try to help getting it running again!