I am still having issues. I have run the co up 20 and down 20 and everywhere in between. changed out map, atmospheric, tps, air box sensors. Nothing. as soon as the computer goes off warm up, where it runs perfect, it will drop idle. I have tried adjusting fuel screws on air mixer and there is no change what so ever when adjusting Idle control valve. You can instantly make it run good if you unplug any sensor driving it into limp home mode which adds goes to the high limit on fuel based on rpm and tps. I have had yamaha dealer run a tech report(forget the name) with every thing Ive done and checked. They cam back with atmospheric pressure sensor, I put one on, no change last night. I have checked the valves clearance, within spec, check cam timing aaaagain, correct. I have also confirmed check valve in tank works, confirmed correct fuel pressure. I will post this as it's own thread but if anyone has any thoughts, please share.
I am jelous of people who simply adjust the co or tps settings and their sled is fixed. This is a friends sled that I now have about 40 hrs in, as my sled sits there needing a drive shaft change.
I am jelous of people who simply adjust the co or tps settings and their sled is fixed. This is a friends sled that I now have about 40 hrs in, as my sled sits there needing a drive shaft change.
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My Supercharger would act goofy like this and the only fix was to unplug the pressure sensor on the throttle bodies. Dave at Hurricane supplied me with little box that I piggy backed into that sensor to spoof the sensor as to not see the code and my problem was solved. So in the process of trouble shooting a friends Apex like these that would fall on their face and stall we came to the conclusion it was a similar problem. It was a strange voltage drop that would cause that pressure sensor to not read correctly. I wounder if this box that helped us fix my supercharger would cure this as well.
musselman
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I had a wire rub through in the nose of the sled on the pink wire going to the front pressure sensor. This caused my sled to stall and after fixing has not stalled since, although the idle still drops sometimes, I need to look at the valves.
tom, did he have any voltage reading to look for, or resistances to look for. Yamaha has nothing on these sensors to test from or to take live readings while running.
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I am not sure on the voltage of the sensor. The key is to make the voltage just enough to keep the error from showing on the gauge.
Rock Zam where are you? This could be the next yamheater
stevewithOCD
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Does it run good except when you come to a stop then it stalls?
yup, once it is warm in the shop, outside, with air box, without, with gauge installed and without. starts great.
stevewithOCD
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Ok, this happened to SEARGE here on TY. He would stall at every stop. Dealer changed everything. Rev-It-Up in Rangeley got it ok'd by Yamaha to change the WHOLE injector system under warranty. The dealer believes it may have been a harness to the injectors that wore through...i'll call him to chime in
Did you try the coolant temp sensor? Maybe when it reads temp as (within operating) it's sending the ecu a reading way out of range. We used to solder a resistor between the wires of the sensor when asphalt racing to trick the ecu into thinking the engine was already warm when we first started it. You could try some different resistors to see if it fixes the problem.
Yes, I swaped it out and also used a a jumper I have to simulate a warm sled to test if it would not idle cold if the sensor said it was warm. Still stalls
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If your high mileage Apex stumbles when it is cold and hunts for proper idle . Runs strong but will stall when coming to a stop after a good pull, will restart right away and set no error codes check your valve adjustment .
You will need to pull off oil tank and delta box for proper access.
You will find all or most valves on the tight side . The valves pound themselves into the head changing clearances .
All of mine were tight . Exhaust were worse . I replaced the cam chain tensioner while I was there .
17.000 miles on it now and it runs like new . It made a huge difference . I think I was at 12,000 when the issues started .
The symptoms are the same as a street bike. The reason I think most don't believe this is the issue is because Yamaha says 25,000 miles before valves need attention . The difference is our sleds are always under load 5 - 10 k rpm. These are constant rpms where as a bike rpm varies more going through gears. Racers check valve adjustments often.
You will need to pull off oil tank and delta box for proper access.
You will find all or most valves on the tight side . The valves pound themselves into the head changing clearances .
All of mine were tight . Exhaust were worse . I replaced the cam chain tensioner while I was there .
17.000 miles on it now and it runs like new . It made a huge difference . I think I was at 12,000 when the issues started .
The symptoms are the same as a street bike. The reason I think most don't believe this is the issue is because Yamaha says 25,000 miles before valves need attention . The difference is our sleds are always under load 5 - 10 k rpm. These are constant rpms where as a bike rpm varies more going through gears. Racers check valve adjustments often.
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I posted this on the other thread also. Is this just an issue for older Apex’s pre 2010? I have a 2013 Apex with 8000 miles and zero issues so far. Wondering if this is something I may encounter in the future as the mileage goes up?
I had the head off, had a head gasket fail between cylinders. I check valves when off, later second guessing myself, I checked valve clearance again in the sled as well as cam timing thinking maybe a stretched chain might throw it off enough. sled had 10k on it.
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Yes you will . Consider it maintenance. We need to do it before recommendation that's all. All engines of this type require valve adjustments . This is a bucket over valve engine with shims in between.
Cam shafts need to be removed and reinstalled .
It's not a difficult job to do for a good handy guy . Only real somewhat special tools you need is a good set of feeler gauges and a inch ft lbs torque wrench. Oh ,,,,,,, and a big bucket of patients.
Attention to detail is important , this is an interference type engine so cam timing is very important or your valves will be talking to the top of the pistons and it is not pretty.
You will make a mess of your sled but it will fall together fairly easily.
