AXYS Down on 1500RPM

[die hard poo]

Update:
So a friend let me borrow his new AXYS(3.5hrs on sled, 52 miles) to try swapping ECU's. So I first swapped MAP sensors to verify mine was good, and there was no change. Then I swapped ECUs, also no change.

So today my dealer is going to check my fuel pressure at WOT on the service report to ensure nothing is wrong with my fuel system. Lastly we are going to verify the TPS is working correctly.

Chad, thanks for the info. I didn't realize they were running so lean below 3500ft. I will throw the resistor in and if we don't find anything wrong with the fuel system or TPS I will pull the head off and do an inspection. I did look through the exhaust valve port into the pistons and didn't see any apparent damage to the exhaust side of the piston or dome, but I suppose there could be damage elsewhere.

 

[richardderkevorkian]

Update:
So a friend let me borrow his new AXYS(3.5hrs on sled, 52 miles) to try swapping ECU's. So I first swapped MAP sensors to verify mine was good, and there was no change. Then I swapped ECUs, also no change.

So today my dealer is going to check my fuel pressure at WOT on the service report to ensure nothing is wrong with my fuel system. Lastly we are going to verify the TPS is working correctly.

Chad, thanks for the info. I didn't realize they were running so lean below 3500ft. I will throw the resistor in and if we don't find anything wrong with the fuel system or TPS I will pull the head off and do an inspection. I did look through the exhaust valve port into the pistons and didn't see any apparent damage to the exhaust side of the piston or dome, but I suppose there could be damage elsewhere.

can you disconnect the power valves and pin them wide open?

 

[die hard poo]

Rich, yes you can disconnect and hold it open however I don't see a real reason since I watched them work correctly and open fully.

Update:
I decided to pull the head off and inspect the cylinders. I did not find any damage. Both pistons looked great on the top as did the cylinders. No signs of damage or scuffing. The head also looked great with no signs of det or lean condition. Put it all back together and took it to the dealer.
Fuel pressure was fine and the only anomaly was the TPS sensor was fluctuating between .947-.952v constantly while shutoff. We even disconnected the throttle cable from the lever and it still was fluttering. So my dealer is ordering up a new TPS to try. That will be here sometime next week.

Here is some pics of the motor opened:

 

[die hard poo]

I also recorded the issue when it is low in RPM. This was when I was going through the mountain pass. Notice when I pin the throttle not a whole happened and the tone of the motor sounds funky, thats because it was only pulling around 7K rpm. Sorry about the fogging over of the lense, there was a lot of ice fog.


Also here is a vid from the same ride once I got the riding area. The sled ran better, but was only pulling 8100rpm. And you can hear every once in a while that the sled doesn't backshift correctly and kinda lugs down on some pulls. Also kinda slower to rev than before.

 

[SRXSRULE]

I tested my EGT sensor this morning and found it to be out of spec, you have to heat it up and then check the ohm reading. It was reading too hot, which would make the ECM deliver more fuel to lower the egt temp. Swapped out the sensor and the sled ran the best it has in the last month. Had my adjustable weights in and even had to add weight on the hill. Eric

 

[randy542]

testing egt

how did you go about testing egt? you said with hot pipe, just bring motor up to temp and then test or out on the mountain testing. and what are the ohms suppose to be? thanks

 

[randy542]

iqridr

i had a question for you, sent you a pm. thanks

 

[AKFULLTHROTTLE]

Sounds like it is time to add some boost and get your R's back! ahahahahaha

 

[Teth-Air]

Not sure if this is relevant or not. My sled has about 1000 km's on it and I am playing with clutching. I dropped weights from 64's to 62's to try and get more top RPM. I found that on the trail I ran into a mid-range bog (fade). It was very reminiscent of the e-tec bog when the clutch was too light and the RPM's increased too fast. It was like the ECM was pulling power out to protect the motor?? I am quite sure I was not banging off the rev limiter unless the Tachs are just too slow to show the RPM?

Anyway it was great in the deep snow at elevation but both the trail up and down it did this.

Went back to 64 gram weights and the problem disappeared.

 

[die hard poo]

Status Update:
I received the new TPS today and went to install it. Well the new one's voltage was fluctuating the same as the old. Thats when I decided to check the supply voltage from the ECU, it too was fluctuating...

So I disconnected the TPS plug and hooked up my 5v tester battery directly to the sensor and it holds voltage rock solid with the 5v tester. I tested both old and new sensors and they both are working correctly.

So then I tested voltage right off the ECU pin (Red/white striped wire, right hand connector, 3rd from the top right) and it to was bouncing from 4.97-4.98v...

Looks like the ECU is sending a fluctuating voltage to the sensor. So now it looks like an issue with the ECU. I also verified my battery that I am using to power the ECU voltage was stable and it's stable at 12.14v.

Also since I was at the throttle body, I went ahead and pulled the reeds to inspect those. They looked perfect, no chips at all. This has got to be a electronic issue. And looking more like the ECU..

 

[IQRIDR]

Man that is wierd. I hope you get it figured out. Such a small variance...

 

[sledheader]

Status Update:
I received the new TPS today and went to install it. Well the new one's voltage was fluctuating the same as the old. Thats when I decided to check the supply voltage from the ECU, it too was fluctuating...

So I disconnected the TPS plug and hooked up my 5v tester battery directly to the sensor and it holds voltage rock solid with the 5v tester. I tested both old and new sensors and they both are working correctly.

So then I tested voltage right off the ECU pin (Red/white striped wire, right hand connector, 3rd from the top right) and it to was bouncing from 4.97-4.98v...

Looks like the ECU is sending a fluctuating voltage to the sensor. So now it looks like an issue with the ECU. I also verified my battery that I am using to power the ECU voltage was stable and it's stable at 12.14v.

Also since I was at the throttle body, I went ahead and pulled the reeds to inspect those. They looked perfect, no chips at all. This has got to be a electronic issue. And looking more like the ECU..

DIdn't you say in an earlier post that you swapped in a known good ECU with no change?

 

[die hard poo]

UPDATE:
So earlier I was using a small lithium ion battery for the 12v source for ECU testing, a friend suggested I use a regular car battery to test, so I used my lawn mower battery which had 12.26v to test and sure enough the voltage was steady coming out of the ECU and TPS.

So for whatever reason the little lithium ion battery wasn't giving a clean voltage even though I tested the voltage straight out of the battery as well...

Anyways I put it all back together and went for another test run with the new TPS in and it runs exactly the same, down on RPM and kinda lazy getting there. Feels like its a pro rmk power, maybe a few hp less. I am giving up and giving it to my dealer. I doubt theyll find anything cause I have combed just about everything I could on this sled.

 

[die hard poo]

DIdn't you say in an earlier post that you swapped in a known good ECU with no change?

You are correct which is what was throwing me for a loop. Turns out I was using the wrong style battery for a 12v source.

 

[wfieldin]

Just for grins, any chance the fuel filter is clogged?

 

[Sheetmetalfab]

Just for grins, any chance the fuel filter is clogged?

All there is in the axys is an in tank screen.

 

[rrjames]

So did you adjust the TPS? Better yet did you have your dealer adjust the tps? Simply replacing the tps won't always fix a mis adjustment issue. I'm sure the dealer you bought the sled with would be happy to perform this simple check.

 

[die hard poo]

Yes, new TPS was adjusted to spec(first one was out of spec when I bought the sled, I adjusted when new and was good when I replaced it) .700v base, .95v idle.

And no fuel filter on the AXYS, I did check fuel pressure off the pump (110 psig), but I couldn't check the return side where I am guessing it is regulated to 58-60psig since I didn't have a T or a male quick connect to make a T for the return side...

 

[die hard poo]

Update:
Tried swapping out the VES analog converter since another thread suggested to try that. Unfortunately another failed attempt.

So I put the stock pipe and stock 68g weights and black spring(120/320) and it will only pull 7800rpm with this setup at my house. Taking it to the dealer next week.

I am so fed up with this thing...
Any other suggestions before I admit defeat?

 

[sledhappy]

Update:
Tried swapping out the VES analog converter since another thread suggested to try that. Unfortunately another failed attempt.

So I put the stock pipe and stock 68g weights and black spring(120/320) and it will only pull 7800rpm with this setup at my house. Taking it to the dealer next week.

I am so fed up with this thing...
Any other suggestions before I admit defeat?

Good Luck i wish I could give you some advice. I know it is frustrating. I am also taking my sled to the dealer this week to look into the computer and make some adjustments. I will let you know what i find. (if you throw a turbo on all you have to do is turn up the boost )