i just did a re-build and the car has been running real strange....it hesitates and stumbles when i firts take off from a stop, the motor is a dohc zc and i have a pr4 ecu im getting codes 9 and 10 (#1 cyl. pos & iat) but i was told if the car is in closed loop it might not show a code for it, help!!!

 

uberdata

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Beau Gotti &raquo;</TD></TR><TR><TD CLASS="quote">uberdata</TD></TR></TABLE>any other way??(can the problem be fixed by changing settings(timing) or replacing sensors) im n/a at the moment (gotta try to smog the car)

 

ttt

 

he meant it's running Open Loop. Cars with O2 sensors are feedback controlled systems or closed loop. The IAT sensor is another signal. If the signal isn't present or perhaps way off, then the ECU goes into Open Loop using preset parameters. Problem is it doesn't account for engine wear, etc.

 

reset the ECU and see what happens

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Beau Gotti &raquo;</TD></TR><TR><TD CLASS="quote">reset the ECU and see what happens</TD></TR></TABLE> i did and codes 9 and 10 come back<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Reelizmpro &raquo;</TD></TR><TR><TD CLASS="quote">he meant it's running Open Loop. Cars with O2 sensors are feedback controlled systems or closed loop. The IAT sensor is another signal. If the signal isn't present or perhaps way off, then the ECU goes into Open Loop using preset parameters. Problem is it doesn't account for engine wear, etc. </TD></TR></TABLE> oh my bad....open loop. so i could be in open loop since the iat is bad??

 

Yes because air temp is a good indicator of how dense the air is. If the air temp sensor is bad, the ECU will think it's a constant value (let's say 75 degrees) when actually it could be 90 and varying. Get another sensor and try it out, to make sure the problem isn't in the wiring.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Reelizmpro &raquo;</TD></TR><TR><TD CLASS="quote">Yes because air temp is a good indicator of how dense the air is. If the air temp sensor is bad, the ECU will think it's a constant value (let's say 75 degrees) when actually it could be 90 and varying. Get another sensor and try it out, to make sure the problem isn't in the wiring. </TD></TR></TABLE> cool thanks alot!!