phazer max issue

[drumaps2003]

I recently bought a '07 mtx/mtn with low miles in great shape. after changing plugs, oil change, etc. I finally got to ride a bit. after a couple short rides the machine start to act weird and threw a code for a crank position sensor. went ahead and changed that out after the headache it was to get in there.
prior to this issue the machine would start up after maybe three cranks. now I have to crank for quite some time to get it. it'll crank and crank, then it'll crank and start to catch, then eventually it'll start. a quick shot of juice definitely speeds the process up.
no codes, fresh gas, changed the plugs before doing the sensor.
no codes showing, battery seems good.
any ideas what this may be? I've read about the cold start recall, but not sure if this recall was addressed. I know the ground issue was, so hoping it was.
this may be a non issue but the sled came from about 7000 ft and I brought it down to sea level. could anything be thrown off by that change?
thanks in advance, just worried about draining the battery in the field if this continues as there isn't a pull start to backup.

 

[74Nitro]

I recently bought a '07 mtx/mtn with low miles in great shape. after changing plugs, oil change, etc. I finally got to ride a bit. after a couple short rides the machine start to act weird and threw a code for a crank position sensor. went ahead and changed that out after the headache it was to get in there.
prior to this issue the machine would start up after maybe three cranks. now I have to crank for quite some time to get it. it'll crank and crank, then it'll crank and start to catch, then eventually it'll start. a quick shot of juice definitely speeds the process up.
no codes, fresh gas, changed the plugs before doing the sensor.
no codes showing, battery seems good.
any ideas what this may be? I've read about the cold start recall, but not sure if this recall was addressed. I know the ground issue was, so hoping it was.
this may be a non issue but the sled came from about 7000 ft and I brought it down to sea level. could anything be thrown off by that change?
thanks in advance, just worried about draining the battery in the field if this continues as there isn't a pull start to backup.

Did you use the complete Yamaha stator with pickup coil?

 

[ATV PRO #11]

Could be as simple as an exhaust leak for start up.
Altitude change factors would only be the in clutching not computer. Updated for that year I believe ended in a -10 (not -00) on the back of the ecu. (May also be -20, -30 but won’t be a -40 as that’s newer models with the extra oil pressure sensor)
Are you able to check voltage of battery after a day of sitting. Then while it’s running?

 

[ATV PRO #11]

8GP-00 is the old 07. Sorry it’s marked on front top right side. You can see it with side cover off.

 

[drumaps2003]

Did you use the complete Yamaha stator with pickup coil?

I did not, I bought the pickup separate and kept the working yami stater in there

 

[drumaps2003]

just took it for a quick ride. start up was a bit better, once it starts initially I can shut it down and then it'll start right up again. weird.

the exhaust leak mentioned above... what does that effect?

 

[74Nitro]

I did not, I bought the pickup separate and kept the working yami stater in there

Ok. Sometimes I have seen these be polarity sensitive, so try switching the wires in the plug.

 

[drumaps2003]

Ok. Sometimes I have seen these be polarity sensitive, so try switching the wires in the plug.

funny you mention that. so the stock wires were black and white I believe, the new pickup had blue and green. so I called the company to ask what order they went in in relation to the existing on the pig tail... their response was " try it one way, if it doesn't work, switch it."

seriously. so I tried it one way and when they are reversed there is no starting at all. switched it and it works.

 

[ATV PRO #11]

What was the number on your ecu?

Exhaust leaks usually right at the donuts at the head.
Symptoms long cold starts
Backfire on decel
Stalling when coming to hard stop.
If you have long start up and no other symptoms may be onset. About 1/2 hour to dig into. Under tank.

 

[74Nitro]

funny you mention that. so the stock wires were black and white I believe, the new pickup had blue and green. so I called the company to ask what order they went in in relation to the existing on the pig tail... their response was " try it one way, if it doesn't work, switch it."

seriously. so I tried it one way and when they are reversed there is no starting at all. switched it and it works.

I just know this because I've often done this type of repair on various machines when the pickup coil cannot be bought separate from the stator (bikes, atv's etc) and some machines are sensitive to this. They are difficult to start and when started usually idle erratically. Wire colour means nothing here because we are using an aftermarket coil.

 

[74Nitro]

Imo, exhaust leaks have no effect on running since there is no 02 sensor. Will cause backfiring when slowing down however, especially with throttle closed.

 

[blueironranger]

Are the little vacuum lines hooked up and in good shape on the back of the airbox? The ecu does reference those during startup to get the firing order, very easy to miss hooking back up when re-installing the airbox .