CEL & TRAC after SUB O2('s) deleted on OBD1 SC400
03-18-24, 01:55 AM
#1
CEL & TRAC after SUB O2('s) deleted on OBD1 SC400
Kinda a noobish question but I'm stumped and lost on this one problem trying to get past it; plz forgive me 
(maybe im just blind n dumb + am still learning)
I've recently installed a set of them catless hurricane longtube headers (+an EGR delete) on my 93 SC400 (OBD1) and along with it had completely disconnected/deleted the sub 02's from the rest of the (custom) exhaust. I've read that on OBD1 we can run w/o the sub o2's and it shouldn't throw a code or affect tune; so I've just removed the sens. and left the plugs disconnected for this setup and it seems to be quite the opposite for me. The cel and trac light show up instant on cold start and when diagnosed I get codes for the sub 02's signal (27 & 29). Any other causes/fixes/remedies for this? I'm not trinna run defoulers since I no longer have the sub o2 bungs/ports and am searching for solutions/methods before my last efforts; the plug-in emulators route ($250ish for both +shipping). It had a cel before installation (once I first got the car), but that was due to the one of the main o2's. I've also read that wiring the subs to the main O2's could work... Lmk what options or best approaches are, thx.
(maybe im just blind n dumb + am still learning)I've recently installed a set of them catless hurricane longtube headers (+an EGR delete) on my 93 SC400 (OBD1) and along with it had completely disconnected/deleted the sub 02's from the rest of the (custom) exhaust. I've read that on OBD1 we can run w/o the sub o2's and it shouldn't throw a code or affect tune; so I've just removed the sens. and left the plugs disconnected for this setup and it seems to be quite the opposite for me. The cel and trac light show up instant on cold start and when diagnosed I get codes for the sub 02's signal (27 & 29). Any other causes/fixes/remedies for this? I'm not trinna run defoulers since I no longer have the sub o2 bungs/ports and am searching for solutions/methods before my last efforts; the plug-in emulators route ($250ish for both +shipping). It had a cel before installation (once I first got the car), but that was due to the one of the main o2's. I've also read that wiring the subs to the main O2's could work... Lmk what options or best approaches are, thx.
03-18-24, 12:12 PM
#2
Is your SC400 a CA-NY spec car? If it is, then the ecu behaves more like a OBD2 car than a OBD1 car.
If you still have the rear O2s, you can plug them back in then zip tie them to the bottom of the car. That supposedly works with the OBD1 cars but not with OBD2.
The only other options you have would be to run electronic O2 sims (emulators you mentioned) or just move up to a standalone ecu. The perk of the standalone being the ability to tune and make even more power out of your current setup.
If you still have the rear O2s, you can plug them back in then zip tie them to the bottom of the car. That supposedly works with the OBD1 cars but not with OBD2.
The only other options you have would be to run electronic O2 sims (emulators you mentioned) or just move up to a standalone ecu. The perk of the standalone being the ability to tune and make even more power out of your current setup.
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JuicySucculentPork (03-19-24)
03-19-24, 06:37 PM
#3
Checked and car is FED/Canada spec. Tested it out whilst clearing codes; only temporary, but no go sadly 
I'll probably just settle with the sims for now since I'll just be daily driving it to work and around (street build plans eventually). I do wanna get my hands on an AEM Infinity setup but really itching to do a manual swap first :P Thanks for the info!
I'll probably just settle with the sims for now since I'll just be daily driving it to work and around (street build plans eventually). I do wanna get my hands on an AEM Infinity setup but really itching to do a manual swap first :P Thanks for the info!
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