idle setting

96ltz
11-06-2002, 10:05 PM
I have a 96 with an automatic and was wondering if anyone could tell me what temp. the idle should reach 550 rpm with the a/c off and stock programming?
Thanks in advance

96z
11-07-2002, 09:59 PM
176* F

96ltz
11-07-2002, 10:12 PM
:bow: thank you:)
Now my next question is does the temp have to stay above that so the pcm will learn fuel settings? My car only reaches 170-174 since I flushed it and put a 160 thermostat in. My auto xray scanner tells me its going into closed loop but the block learns will not show anything but 0. Dont know if it matters but the rear o2s died about the same time and I have an air pump code.

96z
11-09-2002, 12:38 AM
HMMMM did you remove the air pump? The rear O2's are only used to make sure they are there.

Not sure about the temp needing to stay above to learn fuel trims, my guess would be not.

96ltz
11-09-2002, 12:47 AM
I did remove the air pump but it was throwing a code anyway (I went by the dealership and got the new pump with kit under the recall and will be putting it on this weekend). Just wondering why the computer wont "learn" and if it could be related to the rear o2s or the low temp thermostat?:confused:

90 Z28SS
11-09-2002, 03:50 PM
If your engine never meets the required temp for closed loop it would remain in open loop . I would have to assume though that your car is NOT set to switch to open loop at a coolant temp above 170* . So I would rule that out since you said your car does get up to 170-174 .

I know for OB1 cars a missing air pump will not cause the car to stay in open loop . But with the much stricter emmisions guidelines with OBD2 , the missing air pump and code could be why the PCM is staying in open loop or limp mode . I can't tell you that as fact though , just that is certainly a possibility .

96ltz
11-09-2002, 08:36 PM
:cool: Thanks for the reply.
It seems to go into closed loop ~140 from a cold start and as much lower (seen ~90 or so ) from a warm start. I dont know how to tell if it is in limp mode. The copmuter AFAIK is factory programmed and I only have a flowmaser muffler, G2 air box w/k&n filter.
It worked ok with all of these, then I replaced the opti, wires, plugs, new 1le elbow (mine was ripping), front o2s, and did the thrrotle body bypass. After this I started having alot of problems I finally traced to 1 bad plug wire on the drivers side and The opti was somehow crossfireing on the pass. side. I replaced the wires and put me old opti back on after cleaning the cap and rotor and no more misfires and the short/long term fuel trim %s seem to straiten out but It wont set the block learns:confused:

90 Z28SS
11-10-2002, 12:49 AM
Originally posted by 96ltz
It seems to go into closed loop

What scan tool , or scanning software are you using ? FWIW , most scanners I have seen there is a display that tells you if its in closed or open loop .

96ltz
11-10-2002, 12:57 AM
Auto xray scanner and it does show open or closed loop I just couldnt remember exact temps :)
The scanner does not show a limp mode AFAIK