My car will not go into closed loop. I have a scanner that is reading the coolant temp at 185 degrees per the computer, I have a new heated 02 sensor in my exhaust header, I can start, idle, drive any speed for any length of time and the car stays in open loop according to the scanner. After much searching, these were the only requirements that I could find that caused the car to not go into open loop, min speed, min temps, 02 working and reading properly, min time requirements. I can't find any other ideas. This is an 88 gta l98 tpi with performance resource chip and bolt ons only. Thanks for any help in advance.
Bill

 

my only idea would be that the o2 sensor isnt heating up...

when did you first notice it wasn't going into closed loop? what mods did you do before you noticed it...

 

I just got the car recently, it was pretty much stock and then i did all the bolt ons that i have listed in my sig plus a performance resource chip, plus i got an old scanner and its been reading open loop since the first time i used it. It was showing a code 45 and not any crosscounts on o2, i added the new heated o2 today and the code disappeared and the crosscounts started showing up, but still shows open loop no matter what. I checked the sensor at the point of the wire going into the unit itself and its getting voltage when i start the car and it's grounded good, obviously its working if the scanner is showing the readings from the sensor as well. The car has seemed to me to run about the same even before the mods, seems rich all the time, can smell the gas and drinks the fuel as well, doesn't really run like i think it should either.

bill

 

do you still have cats?

 

nope, edelbrock headers to y pipe and 3 inch to 40 series straight through

 

might want to check to see if it's your ECM... replace it with a new one from discount auto or some type of auto store, and see if it'll go into closed loop.

 

I have another ecm from an 89 350 formula, what would happen if i plugged it in with my 88 chip in it?

 

well, if the 88 has the cold start injector and the 89 doesn't... i dont think it'll work.

 

Some parameters related to Closed Loop Mode:

Closed-Loop Operation Parameters
CTS < 14.7°C (58°F) for 75 seconds;
CTS >14.7° (58°F) and < 40.7° (105°F) for 51.4 seconds;
CTS >40.7°C (105°F) for 12.5 seconds;
O2 >0.699V & O2<1.99V for 10 seconds;

Coolant Temperature Sensor Related Parameters
BLM enabled between 50°C (122°F) and 140°C (284°F)

Diagnostic communication enabled at 70°C (157°F)

Hot closed-loop timer enabled above 70.3°C (158.5°F)

 

Toss your stock chip back in the computer. See what happens, maybe your new chip has issues.

I wrote my custom chip to turn on closed loop at 150*