Rapid bouncing idle problem
Posted: September 10th, 2009, 6:46 pm
Heres the back story:
I switched out my TB with a stock diameter MX6 TB a while back and had a similar idle bouncing issue and had it solved by removing the IAC valve on the MX6 TB and replacing it with the stock MX3 IAC valve. However, I removed the spacer between the TB and IM and realized I made my car very sluggish by doing so.
I reinstalled the spacer after slightly porting it and plugged in all the harnesses/sensors and turned on the motor. I noticed the idle starts around 2k rpms then drops to 1.5k, sits for several seconds, then bounces back and forth as if someone is tapping the throttle every 1.5 seconds or so. After the engine warms, the idle drops to about 1k rpms and continues doing the bounces up to 1.5 rpms or so.
I disconnected the IAC valve and the idle dropped a little (maybe a couple hundred rpms). It would idle nicely for a few seconds, then it will continue with the bouncing.
This is what I changed out in the first place:
1) Stock MX6 diameter TB
2) Stock MX3 IAC valve (switched out with mx6 IAC which was giving me problems)
3) Removed the TB/IM spacer (but just reinstalled it and it gave me the new issues above)
4) Removed the TPS from stock mx3 TB and have it installed on the TB
Im thinking it may also be that we didn't properly set the TPS all this time? Because removing the IAC sensor seems to have no effect on the problem. When we swapped the TPS, we did it when the TBs were unbolted and we just unscrewed it and screwed it onto the new TB before installing it to my IM.
I switched out my TB with a stock diameter MX6 TB a while back and had a similar idle bouncing issue and had it solved by removing the IAC valve on the MX6 TB and replacing it with the stock MX3 IAC valve. However, I removed the spacer between the TB and IM and realized I made my car very sluggish by doing so.
I reinstalled the spacer after slightly porting it and plugged in all the harnesses/sensors and turned on the motor. I noticed the idle starts around 2k rpms then drops to 1.5k, sits for several seconds, then bounces back and forth as if someone is tapping the throttle every 1.5 seconds or so. After the engine warms, the idle drops to about 1k rpms and continues doing the bounces up to 1.5 rpms or so.
I disconnected the IAC valve and the idle dropped a little (maybe a couple hundred rpms). It would idle nicely for a few seconds, then it will continue with the bouncing.
This is what I changed out in the first place:
1) Stock MX6 diameter TB
2) Stock MX3 IAC valve (switched out with mx6 IAC which was giving me problems)
3) Removed the TB/IM spacer (but just reinstalled it and it gave me the new issues above)
4) Removed the TPS from stock mx3 TB and have it installed on the TB
Im thinking it may also be that we didn't properly set the TPS all this time? Because removing the IAC sensor seems to have no effect on the problem. When we swapped the TPS, we did it when the TBs were unbolted and we just unscrewed it and screwed it onto the new TB before installing it to my IM.
