Sketchy Advance
04-05-2008, 08:49 AM
#1
The Duke of Earl
Thread Starter
Join Date: Mar 2008
Location: L-Town
Posts: 96
Likes: 0
Received 0 Likes
on
0 Posts
Sketchy Advance
Over the past two years Ive been experiancing a hesitation at the bottom of all my gears. It feels like the timimg advance is messing up because it changes performance alot. Sometimes it almost misses and every once and a while it runs better then ever. I can feel something "turn on" and my car hauls ass. Sometimes it just lags unless I give it at least 1/3 throttle. Please help!!! I dont want to go to the dealership!!! I think its either the throttle positioning sensor or my O2 sensor. Has anyone had this problem?? I know its just a sensor but I cant replace them all. :crazyr:
04-05-2008, 11:27 AM
#2
To test your tp senser you have 3 wires on is hot one is ground and one is signal. Keep it all plugged in and back probe the connectors with a paper clip. The hot wire should have 12 volts the ground next to 0.2 volts or lower and the signal the signal should change as you press on the gas so next to .5 closed and next to 4.5 fully open. Look for a smooth voltage increase as you step on the gas you should have no flat spots or drops in voltage.
If you think it is your o2 senser unplug it you will get a code but it should drive better. I could go on and on why this happens but in closed loop you ecm is using the o2 senser to adjust long term and short term fuel trim in open loop you ecm ignores the o2 senser input and gos of pre programed setting aka base fuel map. Open loop and closed loop are determined by the tp senser input among other things. If you unplug it the ecm will go into limp home mode it will only use the base fuel map.
To check you timing short your scs connector get out the timing light, it should be on one of the 3 red marks on the crank pulley. You can only see the advance if you have a data logger, obd2 scan tool with a data list or a timing light with adjustable advance. Rule of thumb the timing should advance as you go up with an rpm increase. I do not think it is your timing you would have problems all over the board not just low rpms.
If you think it is your o2 senser unplug it you will get a code but it should drive better. I could go on and on why this happens but in closed loop you ecm is using the o2 senser to adjust long term and short term fuel trim in open loop you ecm ignores the o2 senser input and gos of pre programed setting aka base fuel map. Open loop and closed loop are determined by the tp senser input among other things. If you unplug it the ecm will go into limp home mode it will only use the base fuel map.
To check you timing short your scs connector get out the timing light, it should be on one of the 3 red marks on the crank pulley. You can only see the advance if you have a data logger, obd2 scan tool with a data list or a timing light with adjustable advance. Rule of thumb the timing should advance as you go up with an rpm increase. I do not think it is your timing you would have problems all over the board not just low rpms.
Last edited by Fuse; 04-05-2008 at 11:32 AM.
04-10-2008, 11:08 AM
#3
The Duke of Earl
Thread Starter
Join Date: Mar 2008
Location: L-Town
Posts: 96
Likes: 0
Received 0 Likes
on
0 Posts
Thanks Bro!!! I'll try all of those and let u know... I figured out one of my problems was that thing in the throttle body that coolant goes through was loose!! it was hella blocking that air flow and giving me stupid idle. Up and down for ever!!!