Wont idle down

APEXMT · Jan 23, 2011

Hey guys. I have a mpi sc stage 1 apex. riding it today just basically puting around it decided to not idle back down. it wont come down below 4500 rpms. check all linkage and everything is moving the way it should be. I cant find any hoses off or anything. Also on full throttle it doesnt quite act right either. Like it hits the rev limiter but it not. any ideas?

One thing i have found so far is that if you plug the hose that hangs from the idle air controller with you finger it will idle down. Has anyone ever had one of them go bad?

Wheel House Motorsports · Jan 23, 2011

what rpm is this "rev limiter" kickin in at??

if your getting a leaky air into the thing at idle, that will cause it.. i have a tiny boost line bleeder for boost controller, and just the little tiny amount of bleeder on it will jack the idle up to around 4500. close it it drops right down, sounds like your problem, that would also act like a boost leak if it went bad methinks and could cause a crappy top end power, not sure, never messed with one.

Thistledoo · Jan 23, 2011

I remember reading about this once or twice. The apex has had issues with bending something on the throttle plates or shaft causing them not to close properly.....Can anyone else chime in here??

Linc · Jan 24, 2011

Thistledoo said:
I remember reading about this once or twice. The apex has had issues with bending something on the throttle plates or shaft causing them not to close properly.....Can anyone else chime in here??

Yup, I've seen that when it backfires hard.

Polarisrocks · Jan 24, 2011

How is your coolant level? if you are low and your hiak valve doesnt see warm water it wont idle down for you, if you have an air lock because its the top of the system, check both, pull the little coolant hose off for a sec an see if there is warm coolant to it, or air.

APEXMT · Jan 24, 2011

Ski-Dooin it said:
what rpm is this "rev limiter" kickin in at??

if your getting a leaky air into the thing at idle, that will cause it.. i have a tiny boost line bleeder for boost controller, and just the little tiny amount of bleeder on it will jack the idle up to around 4500. close it it drops right down, sounds like your problem, that would also act like a boost leak if it went bad methinks and could cause a crappy top end power, not sure, never messed with one.

Ok so do you think that the air that its sucking into the IAC is right? As soon as i plug that it idles right down. Just dont remember is it always did that.

APEXMT · Jan 24, 2011

Polarisrocks said:
How is your coolant level? if you are low and your hiak valve doesnt see warm water it wont idle down for you, if you have an air lock because its the top of the system, check both, pull the little coolant hose off for a sec an see if there is warm coolant to it, or air.

coolent is ok- it idles much higher than it would it that was the case. It will actually drive itself it that high.

thamax · Jan 24, 2011

check the throttle body butterfly aligment if the sled backfires hard can cause a mis aligment. The idle air system can get stuck take that black cap off it and make sure its still moves and run the sled up to temp and shut it off an check the to see if it changed. air leaks is the most common problem pressure up your throttle bodies with and soapy water works the best to find leaks

APEXMT · Jan 24, 2011

ok havent gotten very far on this yet. I did switch out the IAC from another apex and it did not help so i gotta say its probably not that. Dont know what ive done but it will come down to about 2000 now but feel it should be less than that. It makes no difference if i am running through the gems controller or not it still wont come way down. I have checked out the tps sensor and that is fine also. Any other ideas would be appreciated.

APEXMT · Jan 24, 2011

thamax said:
check the throttle body butterfly alignment if the sled backfires hard can cause a mis alignment. The idle air system can get stuck take that black cap off it and make sure its still moves and run the sled up to temp and shut it off an check the to see if it changed. air leaks is the most common problem pressure up your throttle bodies with and soapy water works the best to find leaks

Can u elaborate on the misaligned butterflies a bit? I see where they meet in the middle and all looks well but not sure. I discovered that if i push on the linkage down there it will idle down some more but it all looks right to me. It has not backfired either.

NM · Jan 25, 2011

You have probably already checked, but maybe your throttle cable got pulled out of the socket on the bars? If it is not seated properly then you will get a high idle. It should snap in to place.

TApeX_07 · Jan 26, 2011

NM said:
You have probably already checked, but maybe your throttle cable got pulled out of the socket on the bars? If it is not seated properly then you will get a high idle. It should snap in to place.

On this note, double check the lock nut on the throttle body end of the cable. Mine backed out and the cable kept getting tighter and tighter untill the TORS kicked in..

Linc · Jan 26, 2011

TApeX_07 said:
On this note, double check the lock nut on the throttle body end of the cable. Mine backed out and the cable kept getting tighter and tighter untill the TORS kicked in..

That's a good point,, if the throttle cable had pulled out, it should activate the TORS, but if it hasn't triggered it, then I would guess that you have an issue that is causing it to run lean and rev up, or it something that is causing butterflies to stay open ( Bent throttle plates ). Do you have a Lefty throttle? sometimes those will by pass the throttle override and make it rev up.

hobbes · Jan 26, 2011

If the sled did backfire it is possible that you bent/tweaked your throttle butterflies and it is letting in too much air. This wouldn't explain your funny WOT run though. I had my Apex backfire on me once and chased a high idle for almost a year before finding this out.:doh: I switched a whole set of throttle bodies in from a buddy's Apex and BAM, idled perfect. Good luck and let us know what you find out!

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Wont idle down

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