EGT sensor problems...

[ROCKNESTER]

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

 

[Anthony Oberti]

To clarify, you mean the Pipe/Exhaust temp sensor.....not an aftermarket EGT sensor.

 

[Liv4turbo]

You need to raise your psi h and m number 1 or 2 run strait av gas and have fun I had the same problems last year. Stay away from the ethanol It is basically putting water in your motor

 

[ROCKNESTER]

You need to raise your psi h and m number 1 or 2 run strait av gas and have fun I had the same problems last year. Stay away from the ethanol It is basically putting water in your motor

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

 

[mountainhorse]

This is a simple temperature dependent resistive sensor.

I do not believe that the failures would not be related to fuel type, boost levels, nor fuel settings on the EBC.
If you have some ideas & reasons to the contrary.. I'm always open to learn.

IMO...This is an electrical problem that is causing this to fail.. I suspect ECU or VR.

 

[Anthony Oberti]

What about the fact that his pipe just cracked. Suppose it had been cracking for some time and threw off the harmonics of the pipe. If the ECU or VR was bad, wouldnt the sled run like crap everywhere? I don't think psiH or fuel has anything to do with it....personally.

 

[mountainhorse]

I was thinking the same thing Anthony... but this is the same themistor (with different length leads) on it as the Paint shaker 900's.

It could be a vibration problem... Maybe Jack will shed some light on this tomorrow... I guess there is another coming into the shop with similar problems with the EGT sensor probe failing multiple times.

HMMM... This is a wierd one for sure.

EDIT: It seems that the 2011 Exhaust temp sensors have some upgrades to them and are a bit more durable.

 

[mountainhorse]

The problem could also be a defective or broken wire or bullet connector in the harness... Wires can break inside the insulation but not show up on the outside... causing an intermittent problem OR break in connection until the wire is moved again...

Wouldn't be the first time something like this has happened... TPS harness's were famous for this on the early cfi sleds.

This could make you see a failure at the CEL light on the gauge (5 flashes) when the sensor itself is not actually bad...but when you disturb the sensor connectors upon install.. the connection temporarily "fixed"

Did you try one of the "bad" sensors in a known good sled that has no history of any EGT Probe problems?

Remember the TPS harness we replaced on the 1140 Anthony??

Just a theory.

The Photo below was of a TPS harness that was bad inside the insulation...The owner went through 6 TPS sensors (all good...he saved the old ones) before I found the broken wire (thanks Super Dave)

 

[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.

 

[tree climber]

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.

more info please

 

[Anthony Oberti]

But we all run the same fuel.....and I have never lost a sensor in the last 3 years.

 

[mod03rmk800]

Is it possible he has one of the "farting" pro's and that explosion in the pipe is enough to cause the damage?

 

[mountainhorse]

First off... Remove the pipe completely from the sled before you weld it up

Next…..

Have you ever had a Voltage regulator fail on this sled?

Did you test the probe for function at the different temperatures above?

===============================================

Check the Ground wires on the ECU mounting plate for breaks, corrosion and tightness. You should also install extra ground wires for good measure like in this thread. CLICK HERE

Next, install one of your "BAD" EGT Probes into a known good sled and test it there.
=================
Next:
Unplug the ECU-A Connector at the ECU.

Then, Disconnect the EGT probe at the bullet connectors.

Check at pin #5 (W/Blk) in ECU-A for any continuity to ground... There should be NO continuity to ground.

Then, with a test light or VOM set for "continuity" clip one end on the bullet connector, with the W/Blk wire, for the EGT probe to plug into (on the harness side, not the probe side) and the other at Pin #5-ECU-A and move the wire around a bit to see if the wire is broken somewhere inside the jacket or at the connectors.

Check the Blk/Blue wire at the harness-side bullet connector for the temp probe...check that for continuity to ground… Move this wire around as you test like above.

It would be good to find out what the amperage draw should be at a certain resistance value when the sled is powered up…this would allow some elimination of the ECU as a cause. I’ll try to look into that.

The EGT probe is a K-type thermistor...The most common failure for Thermistors is caused by over-current issues. If the ECU is defective and the ECU is drawing too much current through the Probe... the probe WILL fail.

This is why, IF everything else checks out, that I believe the problem to be in the ECU.

In a probe where resistance decreases as the temperature increases, and the device is called a Negative Temperature coefficient (NTC) thermistor.

The last scenario for failure, as Anthony had mentioned… Vibration.

I just got off the phone with Chris Kasel and Erik Vohk… talked about the problem. It is possible that rather than an electrical failure, it is a mechanical failure that would be due to vibration.

Chris made some suggestions for possible changes in the probe hole size into the pipe.

Erik also shed some light on a slightly plausible situation…. That would be related to fuel as Live4turbo hinted to… if at any part of the operation… the sled is blubbering rich and raw fuel makes its way onto the probe…the rapid change cooling of the probe could cause the failure.

The Cats have a similar probe (different values and size) that would fail because of strange vibrations in the pipe.

As Anthony pointed out, the Crack in the exhaust at the turbo flange could also induce vibration as well.

I’d like to see the weld-repair done with some gussets in it at the flange. Also a full pressure test of the pipe to check for any other breaks/cracks under the factory exhaust heat shield.


Milehighassassian, I see where your logic is coming from… but this probe is a stainless steel jacketed probe (see pic below for an idea)… there are no openings for lead contamination etc.

 

[ridgeclimber]

egt temp sensor

I have the 08 800 dragon with the BD PG kit with the mini cooler. For the first two seasons with the turbo I ran VP C12 and premium mix. This year I have been running straight av gas. So far I have not had to replace the oem egt sensor yet. I think maybe running lean and over heating the sensor could cause it to fail. I also use a scotch brit pad and clean the end of the sensor when I have it out. I also never seize the threads on the sensor so you don't over torque the sensor getting it in or out of the pipe.

 

[INKEDRIDER]

DET.

 

[Anthony Oberti]

Let's see if that is true.....look at the top of the pistons? Is there any sign of detonation?

 

[INKEDRIDER]

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.

 

[milehighassassin]

Milehighassassian, I see where your logic is coming from… but this probe is a stainless steel jacketed probe (see pic below for an idea)… there are no openings for lead contamination etc.

Agreed that there is nothing real special about this temp sensor, but wouldn't you think even a coating on top of this probe of say lead, would cause it to change the readings?

I'll try to get some info on the "trick" to fool the ECU.

I have heard that it could be a vibration thing as well. I also heard this is the reason SLP has the band around their pipe, to limit vibration.

 

[mountainhorse]

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.

C'mon guys... What is all this hassle for???

Inkedrider... lets be civil to each other... why the insults??

I understand about the Pro's and the deto concerns... but this is the cfi-4... lots of good running sleds out there without deto issues... from Silber, BD, Aero, HM, Twisted and others.

Rocknester asked for some help...people here are chiming in with some ideas... thats what I like about this place.

 

[Anthony Oberti]

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.

LOL....you are such a moron.....this is not a PRO we are talking about!! Maybe before you are allowed to post on SnoWest you should take an intelligence test yourself. But go ahead and bash my intelligence....that's quite comical. Pretty sure my credentials in "intelligence" would beat yours anyday of the week.....unless you have more letters after your last name than I do. However, this is sleds we are talking about here, and the cool thing is my builder has probabloy forgot more about snowmobiles than you will ever know. Go ahead and call up Jack Struthers....I am sure he would love to hear from someone like you that has it "all figured out". Funny how he isn't having any problems with his Turbo Pros and neither are his customers. For what it is worth....do you personally own a Turbo Pro?