EGT sensor problems...

[Anthony Oberti]

.....gosh the hand warmers on my Pro stopped working yesterday......I bet it is detonation......


Sorry Rocknester....hope you get her figured out pretty soon.

 

[Boyko]

2010 Polaris Assault w/ Boondockers Pump Gas Turbo kit...

I've gone through my fourth EGT sensor now on this sled and i am not quit sure what is causing this repeat problem. i'm running anywhere from 7-8 lbs boost. I typically ride above 6500', but do ride around 5-6k sometimes.


Each time I've lost the sensor I've been under 6500', I've lost three at around 5000', all of these different failures have been riding in California running premium 91 w/ 10% ethanol added fuel.

The recent two failures have been running premium 91 fuel mixed with either 100ll Av gas or with 114 race fuel.

I don't know if the fuel has anything to do with the failures or if the failures are due to an unrelated issues, i.e. over tightening the sensor into the pipe, pipe not being secured well enough to the sled, electrical connection issue... i don't know.

looking for any suggestions or similar stories of this same problem. Thanks,



JESSE

Does the probe seem to be a little bent or distorted? I put together a kit for a Dragon back in 07 and after about 500km the dash was flashing a code at me. I pulled the sensor out and it looked bent, like it cold not take the heat .

I got a short piece of stainless tubing that fit over the probe. I left the end of the probe exposed and flared the other end of the tube so it would fit into the bung in the pipe and seal.

It worked well

 

[SNOW JW]

Sent you a PM

 

[Liv4turbo]

Thanks Liv4turbo, but unfortunately I can't stay away from the ethanol based fuel here in Cali. There is no where that sells our pump fuel without the ethanol added, unless I run straight av, I'll always be mixing some pump in. How many Pipe sensors did you go through?


JESSE

3 and thy are not cheep. PS every time i run race fuel i burn one av burns cooler just my 2cents 3erd year on my 09 dragon

 

[Mag]

I went thru 1 when it was stock, 2 running avgas and 1 so far running 110, when I picked the new one up tonight it had a different part # and was twice as much money.

 

[ROCKNESTER]

I hope your man enough to admit when your wrong because your time is coming, it wont be long till all of the problems that the pro's are having will come down to DET. I am finally figuring out whats wrong with the turbo world its not the manufactures its the consumers, you should have to pass a intelligence test on two stoke engines before you can buy a turbo kit. I suspect you would fail.

Listen Pal, I didn't ask for you negative comments or insults. If you've got a hard on for something or someone on here, take it else where. I'm not interested in reading your posts that show a LACK of intelligence.


Thx to everyone else who has been adding useful ideas/comments

 

[ROCKNESTER]

Went out again this weekend after fixing the break in the pipe connection to the turbo. I thought this would solve the issue of the vibration, but it turns out i may have a hole or crack underneath the heat shield of the pipe. The shield is loose, i can wiggle it with one finger. There is an unusually high amount of pipe wrap insulation that looks to blowing out from under the heat shield of the pipe. I believe that i still may have a cracked pipe or possibly even a hole in it. I'll be taking the heat shield off this week to chase down the possible vibration problem further...

 

[ROCKNESTER]

Took the pipe off the sled to check and see if the pipe was cracked... no cracks, no holes, it looked good even though the heat shield was very loose. I'm not really sure what try next...

 

[mountainhorse]

Any follow up on this??

 

[milehighassassin]

I personally think the problem with these sensors is race fuel. I am assuming it is the lead. I know we never had problems with ours until we started running a race blend.

I have heard you can do a mod to the sensor to trick the ecu. Basically a capacitor.

You can trick the ecu into thinking the pipe sensor works by cutting the wires and on the electrical end, wire in a 8k-10k ohm resistor.

I did that, shrink wrapped the connection and then just left my old dead temp sensor in the pipe.

With the flashing light and dead sensor, timing is retarded while the ecu/motor try to create more heat to warm up the pipe.

There should be no ill effects of kidding the sensor, just try and make sure the motor is warmed up properly before hard pulls and with any mod you do it at your own risk.



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[milehighassassin]

I just type up a long reply but it didn't seem to post.

Cliff notes version: wire in an 8k-10k ohm resistor to get the light to stop flashing.

Edit: And now my reply is there, must be a delay in tapatalk


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[150+ or nothin]

Has anybody else tried installing the resistor? I am also having similar problems. I am on my second one in 50 miles. Does anybody know the algorithm the ECU uses to determine ignition timing and fueling for the egt sensor?

What is the 8-10k ohm resistor equivalent to temp wise? Are we leaving any performance on the table?

This seems like a very viable solution when you can get a digital display of EGT for $200 when the sensor costs $150 as long as we get the resistance right.

 

[milehighassassin]

I have a resistor on my sled. From what I understand with the sensor in fail mode the motor dumps more fuel trying to heat up the pipe. This can cause excess heat. I have heard of guys melting plastic from the heat when they continue to ride with a temp sensor that went bad. This is worse on deep powder days with little airflow.

Timing is not changed. With the diode mod, the ecu will think the pipe is warmed up all the time, you might take it a little easy to start but I have not had any issues.


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[trickle]

is the 8-10k resistor you are using a 1/2W or 1W?

 

[sledstew]

Ok here is something to try, get a multimeter and see where the resistance reading goes wacky, put the sled on a stand and see if the resistance worsens at high rpm vs low rpm(idle). If the problem worsens at high rpm I would look for a ground issue somewhere or pin problem. putting a resistor in the system will not fix your issue,ok let me rephrase- it will fix your issue but not for every different riding condition. High spikes in resistance is usually what kills a thermistor. Ok here is another thought, vibration isnt killing the resistor is it? Maybe some low detonation.

 

[skibreeze]

Ok here is something to try, get a multimeter and see where the resistance reading goes wacky, put the sled on a stand and see if the resistance worsens at high rpm vs low rpm(idle). If the problem worsens at high rpm I would look for a ground issue somewhere or pin problem. putting a resistor in the system will not fix your issue,ok let me rephrase- it will fix your issue but not for every different riding condition. High spikes in resistance is usually what kills a thermistor. Ok here is another thought, vibration isnt killing the resistor is it? Maybe some low detonation.

I think that vibration may have something to do with it, he has the symptoms. Cracked pipe joint, insulation shaking out, it's not far fetched at all that vibration is killing the thermister, it is not the fuel.

 

[milehighassassin]

is the 8-10k resistor you are using a 1/2W or 1W?

The more I think about this I am not sure it matters. I asked the same question. I am still trying to locate my package of left overs.


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[milehighassassin]

Ok here is something to try, get a multimeter and see where the resistance reading goes wacky, put the sled on a stand and see if the resistance worsens at high rpm vs low rpm(idle). If the problem worsens at high rpm I would look for a ground issue somewhere or pin problem. putting a resistor in the system will not fix your issue,ok let me rephrase- it will fix your issue but not for every different riding condition. High spikes in resistance is usually what kills a thermistor. Ok here is another thought, vibration isnt killing the resistor is it? Maybe some low detonation.

The pipe sensor is there to tell the ecu the pipe has warmed up. It does not say what temp the pipe is at. It is either warmed up or it's not. Yes or no, nothing in between.


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[sledstew]

The pipe sensor is there to tell the ecu the pipe has warmed up. It does not say what temp the pipe is at. It is either warmed up or it's not. Yes or no, nothing in between.


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Ok so when the sled is at idle the temp lets say is 300+++ whatever degrees and at 1/2 throttle its 950+++ whatever degrees . The Thermistor sends a resistance signal to the ecu to make corrections on the fuel map. So basically what I am saying is that after your pre start,post start and warm up enrichment of your sled has cycled the engine still uses that thermistor to signal the ECU so maintaing a constant resistance will cause lean and rich cycles in the fuel map somewhere.
Some one that has a dragon should try this: warm up your sled ,then pull the resistor from the pipe and plug the hole.Cool the egt sensor way down with air and see the effects of the engine,then try heating it up with a light flame from like a butane or small propane torch and see what the engine does. I would be interested to hear the results. Because if there is no change I would agree that clamping it is the way to go, but you still are not addressing the real issue just covering it up.

 

[milehighassassin]

It does not tell the ecu it is at 300 degrees or 900 degrees. It just says pipe is hot or pipe is not hot. Il sure there is a tipping point, I don't know what that is. This was dyno confirmed by a local tuner here. He said on a cold pipe the ecu receives a signal and retards timing to assist with warming up the pipe. Once it warms up it send a different voltage/signal to the ecu that the timing can advance for full performance.

Look at it like a regular light switch. Off or on, it does not dim. Make sense?



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