In closed loop the car surges, bucks jerks, etc... Put new O2's in it with no affect.. So I had PCMforless (bryan) give me a pcm with a open loop only provision, car runs good now, we think it is breaks in the wiring from pcm to O2 sensor (s). Has anyone had this problem or similiar? Where do I start to try to find the break in the wiring etc, Scanner shows the sensors as working fine though.

 

yeah i had the same problem. Went open loop also.

 

isnt it bad to always run open loop though? car is running off programmed stats vs closed loop were its gettin new stats as temp/conditions change? am i right or wrong there?

 

will put it in open loop too.

 

if you pull the air pump fuse, you'll have no coolant fans... bad idea for that... open loop, you get crap fuel milage and the pcm cant respond to your mods....

 

I have pulled it before, all it controls is the air pump for emissions, has nothing to do with coolant fans.

 

in my 97 if you pull the fuse for the air pump your turning the fans off too, they use the same fuse. what year is your z ?

 

the only way to keep your car in open loop w/o programming is unhooking an O2 sensor.

the wires for the O2 sensors are very easy to follow so you should be able to see if theres a problem in the harness. now if you hook up a scanner you could actually observe them to see if the pcm is reading the sensors correctly.. that would rule out wiring issues. what youd then check are your BLMs to see if theres any signs of an exhaust leak.

what mods do you have and what yr is your car?