'06 Apex sometimes idles low...almost sputtering...

[jaydaniels]

Revised my post to be a bit more specific. The issue is once its at operating temp, I blip the throttle and then the sled starts idling at 1000RPM. It doesn't recover until I restart the sled, then as soon as I hit the gas goes back to idling at 1000RPM.

Well, here is a a quick check to see if its the check valve going into the tank on the return line. Get the sled up to operating temperature. SHut it down. Pull the return gas line off the tank and place in a pop bottle or something. Start the sled and see if the problem goes away. Just be careful that the bottle is supported becasue gas will be going into the bottle while the sled is running. Also, make sure you don't run the sled long enough to fill it. This is how we discovered an issue on mine with the check valve. The return line is on the chaincase side of the sled.

 

[rayone02]

This interesting post my sled does the same thing. Revs up to about 2500 when warm falls to 1500 then to 1000.

 

[MT.man]

Now that the season is over I can add something to this post. My sled does the same thing , stalls when you come to a stop and then starts right up and runs fine. Sometimes when first started cold it will idle high and then idle at about 900 rpm. Sled started acting this way when it had about 10,000 miles on it but just runs great otherwise. I have noticed that it is not that rare a condition and I am surprised that Yamaha cant just say what they think it is as I am sure that they have seen this condition many times. Any how, this is what I can add. I have checked all the things that have been talked about in these posts, and have taken the entire fuel rail off a known good running sled that does not display the same problems and that covers about all the things that conventional wisdom would dictate. Sled still stalls at times when you come to a stop , no change . I think that the problem could be a senser (however it displays no codes) or maybe a ground problem ( this has been discussed ) but chasing a bad ground requires work than most posters here want to do. My sled now has 16,000 miles and has been demoted to the wifes sled and is ridden about 1000 miles a year but still need to run right as if momma's sled has a problem I have a problem. This is what I have done to fix (mask) this problem. There is a adjustment screw on the throttle body that changes the position of the butterflies and I have turned the screw 1/2 turn and now the sled runs and idles just like it did when new. I had to adjust the real idle control down alot because I had screwed with that trying to find a consistant idle. I would like to figure out the issue because the sled is still a great sled and I would not hesitate to take that sled on vacation and put 1000 mile on it but I would want it to be perfect. Any one here have any insight on this problem ?? The size of this post tells me that this issue is not isolated .

 

[thor452]

MT. Man have you had the throtle bodies synched ever sounds like a great place to start to me.

 

[kinger]

Just a update as I posted in this thread a while back.

Here is what my problem was, this was no related to all the mods on my sled, SC, etc. This could impact a stock sled.

Basically a pin hole in my vacumn line going to the FPR (fuel pressure regulator) it was under the hose. I found it when I just decided to replace all the lines thinking it had to be a vacumn leak.

The picture looks bad because I am stretching it out but with no pressure you could NOT see the leak visually. How it got there, why,???? No one knows. Once fixed the sled idles perfect blips of throttle, etc nothing get it to not stabilize.

Hope this helps

 

[judger101]

seems like it would have had to rub on something? thanks for the update.

 

[MT.man]

I have tried every angle , and taking the throttle bodies off a sled that ran good and displayed no symptoms kinda eliminates most fuel problems.

 

[VermontR]

I have been working on this for 2 years and 5000 miles. I have tried everything. I have a new thought. The apex has a non feedback efi (no o2 sensors) if the air box temp sensor doesnt read correct intermintently the fuel ratio is not going to be correct and the computer doesnt know the difference. Making it stall. I m going to drag it out of the basement soon and check the resistence of the sensor vs my buddys that runs perfect. Just a thought.

 

[kinger]

Double and triple check your vacumn lines the sensors could fail but my money is on the vacumn lines. If nothing else get a new set from a part out sled and just start replacing them, that is what I did and only then did I find the hole, I looked 4 times before and could never find it. The picture above was under the 90 degree angle on the FPR no way to have seen it unless you removed it first.

Good luck

 

[VermontR]

So I have spent hours and hours reading on here and working on my apex trying to fix this problem. I think I have a break through! This problem started around the 9500 mile mark and has gotten worse now at 14,633. CHECK YOUR VALVE ADJUSTMENT! I have not got mine back together yet but my exhaust valves were way out. Spec is .21 - .25 mm and mine were .05 - .09 mm. The intakes were very close but I m adjusting them anyways. They are adjusted with shim pads that I had to order so I will know soon how it runs. I will let you know.

 

[02xtreme]

Double and triple check your vacumn lines the sensors could fail but my money is on the vacumn lines. If nothing else get a new set from a part out sled and just start replacing them, that is what I did and only then did I find the hole, I looked 4 times before and could never find it. The picture above was under the 90 degree angle on the FPR no way to have seen it unless you removed it first.

Good luck

Where are these vacumm lines? And how do you adjust exhaust valves? My sled has these exact issues.

 

[VMX]

My 07 apex started dieing during deceleration shop checked every thing still couldn't fix called yam service they said to check exhaust cam timing that was it skipped a tooth they reset and now it's fine

 

[VMX]

i had a problem with my apex stalling on deceleration shop went through everything still did it they called yamaha teck said to check exhaust cam timing it was off 1 tooth they reset timing and it runs like new again 14,000 mi

 

[BETHEVIPER]

I have two apexes doing this, thought I would drag this old thread up to see if anyone in here with the issues got them fixed. I'm going to try resetting the throttle body stop and make sure the two sides are synced, then resync the air settings on the idle control. This of coarse after I check the tps. My sled does this and has 20,000mls on it. I have a customers sled that had tons of issues, head gasket leaking between cylinders, clutch rusted up and had wrong spring. Now that I have it together, it is doing the same thing my sled is doing. I have just been living with it on my sled but now I have to actually learn something and fix the problem. Sounds like across the board, the CO need to be set lower. Will report back with what I find.

I'm kind of used to screwing with drivability problems, I owned another idle cluster f**k that Yamaha made, 93 Taurus sho.

 

[BETHEVIPER]

I was surprised to find no reference for correct setup for the mechanical stop on the throttle body. Does anyone have anything that might have been put out to the dealers? I have the manual and didn't find anything.