YZFR1
10+ Year Contributor
- 533
- 54
- Apr 8, 2010
-
Atlanta,
Georgia
The car just started doing this a few weeks ago. It drives and works just fine other than that, so this issue never became a priority but is still annoying. 
Basically, when the car starts reaching a full operating temperature the idle rpm's start going back and forth a little bit and even more so the hotter she gets. Doesn't do it when cold. This is not idle hunt though, as it's much slower than a normal idle hunt. They just slowly bounce back and forth between 1000 to 1300 rpm or so.
Also, after i drive her for a bit sometimes the rpms don't drop all the way back but stick around at 2000k rpm for some time before going back to 1000k rpm. It 's really weird.
When it gets hot and doesn't have a high rpm idle, i noticed that if i rev her up and let the rpm's drop they tend to hang around 2k rpm for a few moments before dropping back. Here is a quick video i made with my phone:
It's not in the tune, as it ran fine with the same tune. The car also has an ISC/FIAV eliminator plate on it. So that eliminates that possibility. Initially, i thought it was just the alternator but swapped 3 in it with the last one being a brand new unit. The battery seems good too, 12v before starting and 14v when running. No boost leaks too, the car pushes 20psi all day with w/m injection.
A stuck throttle cable possiblity has been eliminated also, it still does it when i hold the plate shut by hand.
Logically thinking about it, i think it has got to be something with the throttle body but want to get some opinions/suggestions before i start taking it all apart. It has been completely rebuilt and cleaned just a few years ago though. I did play with the BISS screw a little after this problem started and was able to make it not as bad but it's still there, i just patched it up a little.
I'm a little stumped here with this minor annoying issue. Looking to get some suggestions/opinions before i start taking things apart.
Thank you
Basically, when the car starts reaching a full operating temperature the idle rpm's start going back and forth a little bit and even more so the hotter she gets. Doesn't do it when cold. This is not idle hunt though, as it's much slower than a normal idle hunt. They just slowly bounce back and forth between 1000 to 1300 rpm or so.
Also, after i drive her for a bit sometimes the rpms don't drop all the way back but stick around at 2000k rpm for some time before going back to 1000k rpm. It 's really weird.
When it gets hot and doesn't have a high rpm idle, i noticed that if i rev her up and let the rpm's drop they tend to hang around 2k rpm for a few moments before dropping back. Here is a quick video i made with my phone:
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It's not in the tune, as it ran fine with the same tune. The car also has an ISC/FIAV eliminator plate on it. So that eliminates that possibility. Initially, i thought it was just the alternator but swapped 3 in it with the last one being a brand new unit. The battery seems good too, 12v before starting and 14v when running. No boost leaks too, the car pushes 20psi all day with w/m injection.
A stuck throttle cable possiblity has been eliminated also, it still does it when i hold the plate shut by hand.
Logically thinking about it, i think it has got to be something with the throttle body but want to get some opinions/suggestions before i start taking it all apart. It has been completely rebuilt and cleaned just a few years ago though. I did play with the BISS screw a little after this problem started and was able to make it not as bad but it's still there, i just patched it up a little.
I'm a little stumped here with this minor annoying issue. Looking to get some suggestions/opinions before i start taking things apart.
Thank you
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