02 issue
Thread Starter
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
02 issue
Is it common, while scanning, for the 02 sensors to "doze off" for a few frames (1-3 secs) every so often? My wife's H/C car has a slight miss under load (OD) at lower rpms (1700-2100) and I noticed the 02s will have small areas where they stop cycling for a few frames, and wondered if it might be related 
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
A lazy 02 is usually a result of LT headers because of the further back 02 bungs----Many people will install the rear 02's onto the front locations as the rears heat up better and are more sensitive
Also it could just be that your laptop is too slow to react to the rapid 02 oscillations and skips over some of the data in realtime---
A miss can be several things--ignition-plgs/wires/coils---It can be fuel related but in closed loop (P/T) your ecm should be making corrections via your fuel trims to compensate---make sure your ECM is in closed loop after it warms up---sometimes the ECM will have an 02 fault and will get stuck "in open loop fault" check with most any scanner
Also it could just be that your laptop is too slow to react to the rapid 02 oscillations and skips over some of the data in realtime---
A miss can be several things--ignition-plgs/wires/coils---It can be fuel related but in closed loop (P/T) your ecm should be making corrections via your fuel trims to compensate---make sure your ECM is in closed loop after it warms up---sometimes the ECM will have an 02 fault and will get stuck "in open loop fault" check with most any scanner
Thread Starter
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
Thanks TB
I thought if anybody might know on this forum it would be you
I just installed new heads, so I have new plugs, but wires are older. Hope I'm not having issues with wires arching to the header; they are close. Might look tonight to see if I see anything
When it "dozes off" the STFT goes to around -39, so I didn't know if that would be a laptop or O2 issue.
I could put my rear O2s (if I still have them) up front, but havn't researched how to make the conversion to the plug ends
Thanks
I thought if anybody might know on this forum it would be you
I just installed new heads, so I have new plugs, but wires are older. Hope I'm not having issues with wires arching to the header; they are close. Might look tonight to see if I see anything
When it "dozes off" the STFT goes to around -39, so I didn't know if that would be a laptop or O2 issue.
I could put my rear O2s (if I still have them) up front, but havn't researched how to make the conversion to the plug ends
Thanks
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Look at the LTFT's (long term) fuel trims---You should get a code if they go past +/- around 20% The STFT's don't tell you much
Every LT header brand will fit differently-- Mine were so close I had to zip tie them away from the tubes--but still some were only 1/4-3/8" away !! However i bought the Taylor T-50 wires and have NEVER had a burn thru or issue with them sinse
You can put the car in the garage with all the lights off and open the hood with the car running --garage door closed--and see if you see any arching--BUT BE CAREFUL--only do it for a couple mins as you may afficiate yourself !!!!
ALSO If you have a tuner--try turning OFF the LTFT's and see how it runs or if it misses--
Every LT header brand will fit differently-- Mine were so close I had to zip tie them away from the tubes--but still some were only 1/4-3/8" away !! However i bought the Taylor T-50 wires and have NEVER had a burn thru or issue with them sinse
You can put the car in the garage with all the lights off and open the hood with the car running --garage door closed--and see if you see any arching--BUT BE CAREFUL--only do it for a couple mins as you may afficiate yourself !!!!
ALSO If you have a tuner--try turning OFF the LTFT's and see how it runs or if it misses--
Thread Starter
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
Ok; I put the car into open loop and drove it, and it appeared the miss went away.
I had some rear O2s, so I spiced the correct end on them and tried it. THEY DON'T WORK I basically had no fluctuation at all. Just a lazy current change, so that's not going to help me. I hate to spend money on parts I may not need, but I guess I'll try new O2s
Any preferred brand?
I had some rear O2s, so I spiced the correct end on them and tried it. THEY DON'T WORK
I basically had no fluctuation at all. Just a lazy current change, so that's not going to help me. I hate to spend money on parts I may not need, but I guess I'll try new O2sAny preferred brand?
