Early shifting problem, possibly cam related? Please Help.
03-13-2003, 08:48 PM
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Early shifting problem, possibly cam related? Please Help. I have posted this problem in a few different sections as I don't know which one suits it best.
I have an LS1/4L60E powered Holden Commodore which has had a fair bit of work done to it, but I am currently experiencing a problem with the trans shifting from 1-2 a lot earlier than the shift point. I have set it to shift at 6400rpms at WOT but it will shift between 3000-4500rpms. This problem started happening after I installed a cam, the specs are as follows :
Duration - 233/233
Lift - 550/550
LSA - 114
I have my idle set to 850rpms which has a really lumpy/aggressive idle. After idling for a little while it will set off the following codes :
P0121 Throttle Position Sensor Performance
P0154 H02S Circuit Insufficient Activity Bank 2 Sensor 1
I have disabled these codes using LS1Edit so the codes don't appear anymore, but the problem still exists. I am wondering if anyone else has had a similar issue to what I am experiencing and what the outcome was. Sometimes when I first turn the car on if I drive around without sitting at idle until the car warms up I can put the foot down in first and it will shift correctly but then it will eventually begin to shift early once I have driven it around for a while.
Could my problem be due to the size of the cam/lumpy idle interfering with the sensors? When I took it into the dealer they said that the Throttle Position Sensor seemed to be working fine but it was like the transmission wasn't responding correctly to the throttle. Is it possible that the cam interferes with the sensor and then the computer goes into a safe mode where it doesn't listen to the TPS?
Any help will be greatly appreciated.
Brett.
<small>[ March 13, 2003, 09:12 PM: Message edited by: Brett SS ]</small>
I have an LS1/4L60E powered Holden Commodore which has had a fair bit of work done to it, but I am currently experiencing a problem with the trans shifting from 1-2 a lot earlier than the shift point. I have set it to shift at 6400rpms at WOT but it will shift between 3000-4500rpms. This problem started happening after I installed a cam, the specs are as follows :
Duration - 233/233
Lift - 550/550
LSA - 114
I have my idle set to 850rpms which has a really lumpy/aggressive idle. After idling for a little while it will set off the following codes :
P0121 Throttle Position Sensor Performance
P0154 H02S Circuit Insufficient Activity Bank 2 Sensor 1
I have disabled these codes using LS1Edit so the codes don't appear anymore, but the problem still exists. I am wondering if anyone else has had a similar issue to what I am experiencing and what the outcome was. Sometimes when I first turn the car on if I drive around without sitting at idle until the car warms up I can put the foot down in first and it will shift correctly but then it will eventually begin to shift early once I have driven it around for a while.
Could my problem be due to the size of the cam/lumpy idle interfering with the sensors? When I took it into the dealer they said that the Throttle Position Sensor seemed to be working fine but it was like the transmission wasn't responding correctly to the throttle. Is it possible that the cam interferes with the sensor and then the computer goes into a safe mode where it doesn't listen to the TPS?
Any help will be greatly appreciated.
Brett.
<small>[ March 13, 2003, 09:12 PM: Message edited by: Brett SS ]</small>
