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Yamaha throttle postion sensor faults

Discussion in 'Technical and Troubleshooting Torque' started by MarvinTheMartian, May 4, 2006.

  1. The Problem: Yam FZ6N dropped it about a month back, nothing serious just an balance issue, but since then have had an occasional problem with idling and low speed.

    The bike usually idles at about 1100, will now idle occassionaly at about 800 or under; ie it has a tendancy to cut out at the most inappropiate moments, like low speed lane splitting or waiting at the lights. :( :?
    On the trips where the bike is misbehaving it seems to be running a little rough, normally the engine warning light also comes on.

    Now the quick and easy fix has been to turn off the ignition and turn it back on, and everything seems hunky-dorey.

    edit: forgot that the bike will also have a sudden sharp drop in power if doing a fast take off, in first at about 8500 revs

    The solution :?:
  2. No immediate causes spring to my mind since your bike is EFI. Does it use a throttle position sensor (TPS)? This may have been knocked in your fall and could cause hunting at idle, but turning the ignition on and off wouldn't cure this.

    If you're certain that turning the ignition on and off does fix it, then it's obviously related to the ecu. Looks like it could be a case for the dealer...
  3. The power dropping away when accelerating sounds like a problem I had. Does it come back and drop away, so it feels like you are on a rodeo bull? I also had to have some throttlewhen stopped at lights. The problem may be with your carbs, they may need balancing. When I had that problem I was switching between 2 and 4 cylinders, hence the bucking effect.
  4. The fz6 doesn't have carbs, its fuel injected.

    The engine may be generating a weak spark, hence the low idling rpm. This could be related to a dodgy rectifier or coil.

    As soon as that check engine light comes on, I'd be taking it to a dealer. This doesn't sound like the sort of problem that can be easily diagnosed.
  5. I'd be guessing a fuel line or fuel pump.

    One may have been dislodged in the fall
  6. Just for those interested, the fault turns out to be a faulty throttle postion sensor, Yamaha knows the problem but is doing nothing about it [-X.

    The problem is a little mostiure getting into the resistive sensor causing false readings.

    Appears as an intermittent fault, that puts a high petrol content into the cylinders. Once the fault appears the only way to get rid of it is to kill the ignition and restart.

    On my FZ6 the fault occurs when in third gear, with the throttle wound back for about 400m, and then comming to a stop.

    So if you own a modern Yamaha and your Throttle Postion Sensor has numbers OTHER THAN 46 or 47 see about getting it replaced escpecially if the bike is still in warranty.
  7. ok I know i'm coming from left field with my experence but I had a similar experence with the tt600. To correct the problem I had a full throttle balance, TPS zeroed, IAC valve check and clean it was full of oil from the crash. Millibar / MAP sensor line was checked to the ECU for blocks. Reflash with the standard map, and CO setting reset and reset of the idling speed to 1150rpm.

    I don't know if your bike can be reflashed but If its an injected bike it should at least have the trottle's balanced the tps zeroed, co & idel stepper motor check and then it should idle like a singer...
  8. Ah, but the problem is a faulty TPS which Yamaha know is a problem from manufacture, no need to touch anything else, well at least I hope not.
  9. its not touching and fixing its preventative checking... well thats my excuse to pull the fairings off every chance i get.
  10. im having problems with my 03 R6 - spoke to a mate and he reckons almost 100% that its a spark plug cap thats playing up. He said that with the 03's that was the main problems...

    My bike starts fine and idle's fine but when i take off i lose power until 3k-4k and then it pulls fine. So i have to keep it about 3k so a few times this morning hehehe im pulling wheelies off at the lights.

    Its getting dropped off at mick hones this arvo so hopefully its not going to cost me alot of $$$
  11. Well here is a nice one. Not

    It turns out there is a problem with Yamaha throttle postion sensors (TPS), at least on the 2004 FZ6, R6, and R1 from what I've been able to tell from worldwide forums, and possibly 2005 models.

    The symptoms are low power, excessive fuel usage, low idle, motor cut out, rough running, diagnostics may not display a fault. Fault can appear intermittently but once there only way to cure (temporarily) is to kill the engine with the key and restart.

    The fault is moisture ingress to the TPS variable resistor causing bad readings of throttle postion.

    The problem only happens on some TPS but will not happen (supposedly) on TPS with the numbers 46 or 47. Also Yamaha have since fixed this problem and at least in England will do a replacement under warranty.

    I am still trying to find out what's the go here in Australia but watch out there if you own a Yamaha of around '04 or '05 and maybe earlier.

    I will post when I've had word back as to Yamaha's response.
  12. oh so this may be my little problem with my 03 R6.
    there isnt a real loss in power but it litterally puffs (like a lawn mower) under 3k rpms.
    I just dropped my bike off at the dealer and they reckon it is the Spark plug cap.
  13. marvin - how much did it cost?
  14. Spark plug cap? Being the spark lead or the coil?
    If its the spark plug cap then just pull them off... make sure there's a clean contact and that the spark lead is properly inserted into the sheath, and then jam it back on there. I hope your not serious.

    Not sure on when the EXUP on the R6's opens, but it could be an EXUP calibration problem... too much slack in the cables would cause it not to open at all at low RPM robbing you of whatever power is available. When it gets to about 4-5k rpm i'd imagine the EXUP is now opened at about 40% and as such you get your power back.
  15. Not sure yet, still trying to get an answer as to warranty claim or not.
  16. Update on this, have spoken to Procycles Hornsby (Yamaha service centre), who have in turn spoken to Yamaha.

    The result, bring the bike in and we'll verify that it is the TPS, if it is then it will be replaced under warranty. :) :grin:

    Procycles hadn't actually heard of the problem but on searching the web realised that it is a widespread fault.

    One of my major symptoms is: with the throttle wound back in any gear, the engine has a tendancy to cut out. The engine does run quite rough at idle or under about 3k revs, to the point where stopped at lights, I have to put a fair bit of power on to take off and not have the bike quit on me.

    Also when travelling at a steady speed between about 5000 and 6500 revs in top (80 - 100km/hr), I find the throttle plays games - it's like the throttle control is jumping around a bit. :evil:
  17. i dont have that problem only when taking off that it feels like that.

    I emailed yamaha because with the r6's in the US they had a service bulletin regarding the coils where they found that the Denso coils were burning out and they replaced it with Mitsubishi ones. Anyway this is what yamaha said:

    We have not issued such a bulletin to Australian dealers. While we acknowledge that some of our models have suffered problems with coils, we have taken this on a case by case basis depending on such things as age of bike and condition etc. If you believe your motorcycle is suffering from such a problem we suggest you have it inspected by an authorised Yamaha dealer for a report to us. Please understand that this is not a guarantee we will assist.
  18. Finally - the TPS is replaced, took 2 weeks for Yamaha to get the part in country.

    Warranty job all the way :grin: even though the bike was out of warranty by 3 months.

    Procycles Hornsby Service - really friendly and helpful, even though it took longer to do the swap out and recalc than expected. :(
  19. thats good to hear.

    I had mine fixed, wasnt the TPS though - burnt ignition coil. Ended up costing me $100 to get replaced. The US had a recall where they replaced all four coils regardless of warranty.
  20. How do you determine the number of your TPS?