tofastSRX said:yeah. you cheap prick lol
I hope thats it for the BRAAAAAAAAAAAABOGGG. Thanks again TofastF7, Oops, I mean SRX. lol.
TPS and Performance issues?
- Thread starter sideshowBob
- Start date
I hope thats it for the BRAAAAAAAAAAAABOGGG. Thanks again TofastF7, Oops, I mean SRX. lol.
tofastSRX
New member
you *** hole lol
mrviper700 said:
But that would be a funtion of rpm, not load. So the 98-99 CDI assumes you're at or near WOT when spinning at or above a set rpm, leaving some operating conditions unaccounted for. Monitoring throttle angle/position still leaves out some operating conditions but is better than assuming. Manifold vacuum is a key input for load but how you'd measure that on a two stroke I have no clue.
Bob,
As a diagnostic aid, did you try and sweep the TPS through it's range while looking at resistance? In other words, rather than making up a test harness perhaps just hooking up a ohm meter to signal return and signal ground and slowly opening/closing the throttle and watching for spikes, the average TY'r might be able to find a suspect TPS without making a test harness.
I'd assume that the current from most handheld meters is lower than what the TPS sees from the sled so if fretting corrosion is causing resistance spikes it'd show up on an ohm meter. In other words, if you can see voltage spikes with your testing, I'd expect that to show up in a resistance check of the sensor. Of course if the meter current output is higher, one might actually "clean" up the wiper to resistor pad interface which would exhonerate an otherwise faulty sensor.
Could you try monitoring resistance while cycling the sensor? If you see resistance spikes but the spikes smooth out than my assumption is incorrect and the meter current may be cleaning the sensor in which case your test harness may be a better tool that an ohm meter. Also, if the resistor wiper spring force is too low, vibration may be the reason for the erratic output which wouldn't show up unless you replicate the vibrating forces (i.e. testing the TPS on vehicle dynamically vs. in your hand statically).
Thanks for your time and also thanks for sharing Bob.
snomofo said:
snomofo, as the bringer of bad news to ya, ALL prior snowmobiles with a cdi box function this way , they use a std advance curve in a 2 stroke, wether its a srx700 or a 440 exciter. Not all cdi box advance curves even have retard in them some models are just a flat rate of ign timing thru out. There is and was no basis for load control. The TPS in this case was just for merely making a bit more accelaration and midrange cruise gas mpg, it doesnt base the whole ign system off the tps readings,its not that advanced. Your making a mountain out of a molehill.
mrviper700 said:
I guess that's the point I was trying to make. Non TPS CDIs (and breaker point ignitions for that matter) had/have no way of knowing load and infer it based on RPM and hope for the best or as the case with your straight curve example, don't even bother. With a TPS, you now have throttle position which is better but actual load on the engine is still infered.
I'm not suggesting the timing curve is based solely on throttle position, but based on Bob's results, it appears that throttle position input to the CDI may play a larger role or more specifically, is used for more than just enhancing part throttle driveablilty or fuel economy. We're talking erratic signal output not lower/higher signal output due to adjustment.
Maybe all the gains made with the TPS replacement was in midrange (his red head "owned" the SRX until the TPS replacement), and maybe the lack of DCS is due to getting into deto conditions later rather than sooner?
Would you agree that all else being equal and Bob is running his '02 on 85 octane, on a run that progressively opens the throttle to WOT, the sooner we pull spark the later we'll be into deto conditions?
I wasn't trying to make mountians or molehills or tying this to burndowns or performance enhancement, but given that the sensor has been updated twice, it appears that there may have been a quality issue with the TPS and I'd be interested in finding a less complicated way of determining a suspect sensor. Since Bob has a suspect sensor it'd be worth finding whether a simple resistance sweep would identify a suspect part as opposed to digging up hardshell connectors and making a test harness to monitor voltage.
I hope I didn't come across as being disrespectful.
I looked at the TPS diagnostics in the shop manual and the test is rather vaige and appears to be written to only find opens. The spec is very broad and doesn't take into account a dynamic in range failure. While it does have the tech cycle the throttle while monitoring sensor resistance, the spec is from 0 to 5k ohms and makes no mention of a desired smooth change in resistance while cycling.
Bob made no mention of a flashing light (which appears to only self diagnose signal open failures) and I suspect that if he had followed only the diagnostic routine it would NOT have lead him to replacing the TPS.
A shortfall in the diagnostics.
Your thoughts Bob?
Bob made no mention of a flashing light (which appears to only self diagnose signal open failures) and I suspect that if he had followed only the diagnostic routine it would NOT have lead him to replacing the TPS.
A shortfall in the diagnostics.
Your thoughts Bob?
I was away ...just got home.
A bit more info:
I had no water temp flashing with a TPS fault code with my irratic TPS sensor until I either unplugged it or advanced it all the way clockwise or all the way counter clockwise.
The resistance of my TPS fell within the test specs but the resistance reading was very sensitive to throttle/TPS movement and hard for me to tell if it was defective or not until I had the sled running with the timing light, degree wheel, and TPS removed from the carb rack but still plugged into the harness. When I manually rotated the TPS the voltage output being provided to the CDI [checked with a multi meter] was very irratic and showed up in the timing.
With the TPS disconnected the timing was 15 degrees at 1800 RPM and the CDI advance began around 4000 - 4500 RPM and was stable and smooth [although the water temp light was flashing]
With the TPS hooked up and on the carb rack the timing was 20 degrees at 1800 RPM[5 degrees extra] and above 4000 RPM the timing became quite advanced and irratic to the point that I could not find a consistant advance/rpm trend. Even with the sled idling at 1800 and the TPS off the carb rack and being manually moved the timing was all over the map until I rotated it full travel then the timing acted as if the TPS was disconnected.
What has been said about the CDI itself being RPM sensitive and providing its timing curve accordingly is without question...they all work this way... the only observation I have is that the addition of the TPS provides voltage to the CDI to provide extra timing irrelavent to RPM and only relative to voltage contolled by throttle movement and I have observed my defective one providing completely irratic CDI voltage input causing additional advance out of sequence which was creating issues with my sled that I have cured by replacing it with the updated part.
Since I started this thread I have been reading about Polaris XCR TPS adjustments and issues[try a search]...they actually set a full throttle TPS voltage to control timing...and some just disconnect it.
I also think[although I haven't tried this yet] that if you suspect a TPS issue you can unplug it and you would just revert to a conventional CDI that controls the sleds timing only through RPM[like a 1998/99 SRX], the only problem would be the water temp light would be flashing the TPS code constantly.
Anyway enough already...I'm done with this topic.
Bob
A bit more info:
I had no water temp flashing with a TPS fault code with my irratic TPS sensor until I either unplugged it or advanced it all the way clockwise or all the way counter clockwise.
The resistance of my TPS fell within the test specs but the resistance reading was very sensitive to throttle/TPS movement and hard for me to tell if it was defective or not until I had the sled running with the timing light, degree wheel, and TPS removed from the carb rack but still plugged into the harness. When I manually rotated the TPS the voltage output being provided to the CDI [checked with a multi meter] was very irratic and showed up in the timing.
With the TPS disconnected the timing was 15 degrees at 1800 RPM and the CDI advance began around 4000 - 4500 RPM and was stable and smooth [although the water temp light was flashing]
With the TPS hooked up and on the carb rack the timing was 20 degrees at 1800 RPM[5 degrees extra] and above 4000 RPM the timing became quite advanced and irratic to the point that I could not find a consistant advance/rpm trend. Even with the sled idling at 1800 and the TPS off the carb rack and being manually moved the timing was all over the map until I rotated it full travel then the timing acted as if the TPS was disconnected.
What has been said about the CDI itself being RPM sensitive and providing its timing curve accordingly is without question...they all work this way... the only observation I have is that the addition of the TPS provides voltage to the CDI to provide extra timing irrelavent to RPM and only relative to voltage contolled by throttle movement and I have observed my defective one providing completely irratic CDI voltage input causing additional advance out of sequence which was creating issues with my sled that I have cured by replacing it with the updated part.
Since I started this thread I have been reading about Polaris XCR TPS adjustments and issues[try a search]...they actually set a full throttle TPS voltage to control timing...and some just disconnect it.
I also think[although I haven't tried this yet] that if you suspect a TPS issue you can unplug it and you would just revert to a conventional CDI that controls the sleds timing only through RPM[like a 1998/99 SRX], the only problem would be the water temp light would be flashing the TPS code constantly.
Anyway enough already...I'm done with this topic.
Bob
Just an update from my end on this issue. Finally got around to getting my brand new updated tps installed and setup as per the manual on my 01 SRX today and I have to say it made a fairly noticeable difference. Reminds me of the first year I had this machine and the reason why I fell in love with it. Tons of low to mid range power and no more annoying problem code flashing at me. If it continues to run like this I couldn't think of selling it. Wicked fast machine.
Netefrog said:
Did you make a test harness and monitor TPS output and find the same erratic output as SSB did or just swap out the TPS?
Netefrog said:
This is why I started this post...these TPS sensors were recalled and updated on the Yamaha motorcycles for a reason amd if you order a new one from Yamaha for your SRX you get the same updated sensor.
Lack of top end performance is a common complaint on the 2000/01/02 SRXs as they age and some of them in my area never performed well since new. I know replacing and calibrating my TPS sensor on my SRX has made my sled perform like it never has since I aquired it.
Worked for me!
Bob
Bob,
Do you think performing a resistance check of the sensor while cycling it and looking for spikes in resistance would identify a suspect TPS or do you think engine vibration plays a roll? My '01 SRX manual doesn't mention looking for resistance spikes while cycling, just a closed and open throttle spec.
As I was alluding to in my previous posts, I think it would benefit many SRX TY'rs if they could find a suspect sensor with a simple static resistance check while cycling the throttle vs. a dynamic voltage check with the engine running. If spring force of the wiper arm within the sensor is too low, engine vibration can affect the contact between it and the resistor pads. This condition might not show up on a resistance check until engine vibration is added.
Sensor development requires a trade off between excessive spring force (wearing of the resistor pads prematurely) vs. too little spring force resulting in wipre arm lifting (open circuits from vibration). Sounds to me like spring force of the wiper arm is too low resulting in intermittent open circuits which is great for the life cycle of the sensor but useless if it doesn't perform.
You've spent a bunch of time already so if you'd like to send me your failed sensor I could use it to perhaps enhance the diagnostics in the manual and answer whether a voltage test harness is required to properly diagnose a suspect sensor.
Be kinda nice to condemn a sensor before spending coin for a new one or making a test harness if a multi-meter will do.
Thanks again for your time.
Do you think performing a resistance check of the sensor while cycling it and looking for spikes in resistance would identify a suspect TPS or do you think engine vibration plays a roll? My '01 SRX manual doesn't mention looking for resistance spikes while cycling, just a closed and open throttle spec.
As I was alluding to in my previous posts, I think it would benefit many SRX TY'rs if they could find a suspect sensor with a simple static resistance check while cycling the throttle vs. a dynamic voltage check with the engine running. If spring force of the wiper arm within the sensor is too low, engine vibration can affect the contact between it and the resistor pads. This condition might not show up on a resistance check until engine vibration is added.
Sensor development requires a trade off between excessive spring force (wearing of the resistor pads prematurely) vs. too little spring force resulting in wipre arm lifting (open circuits from vibration). Sounds to me like spring force of the wiper arm is too low resulting in intermittent open circuits which is great for the life cycle of the sensor but useless if it doesn't perform.
You've spent a bunch of time already so if you'd like to send me your failed sensor I could use it to perhaps enhance the diagnostics in the manual and answer whether a voltage test harness is required to properly diagnose a suspect sensor.
Be kinda nice to condemn a sensor before spending coin for a new one or making a test harness if a multi-meter will do.
Thanks again for your time.
snomofo said:
...Bob
bluemonster1
LIFE MEMBER ONLY ONCE!!!
so getting a new TPS sensor will solve my 02 SRX woes then....seems simple enough..but what about calibration..what has to be done here.
bluemonster1 said:
IMO:
The only time a new TPS will help is if your current one is defective or out of adjustment. Just replacing the TPS would be be a shot in the dark and possibly a big waste of money unless you determine your current one is actually not working properly.
You could build a harness and track the ignition timing and voltage with a timing light and multi meter like I did.
or
Another thing you could try is unplugging the TPS and take the sled for a blast or 2...it will flash the code but the CDI should revert to the preprogrammed ,[RPM controlled only], ignition curve that is unaffected by the TPS and throttle position...not positive it will work as I have not tried this...but it may be worth a try.
Bob
bluemonster1
LIFE MEMBER ONLY ONCE!!!
BOB..what is the new part #..I came up with 5Fl-85885-00-00 from 1 site.Is this the new # or old number.I have a chance to order one locally tomorrow and get by end of week and perhaps get it at a dealer price...my stepson's friend's mother and father own one of the Yami dealerships here.
bluemonster1 said:
That is the original part number, it has been updated twice since then!
Current TPS part number:
5FL-85885-02-00