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markdandurand
11-30-2003, 02:44 PM
I recently added Basanni headers and offroad X pipe to my 4.6 liter modular motorAmerican Iron car. Mil eliminators were used with O2 sensor connectors. I made several laps at Road Atlanta before the check iron light went on. Since oil pressure / temperature and water temp was OK I continued driving at a somewhat reduced pace. Soon thereafter the engine would only run at reduced RPM. I continued and the engine RPM continued to drop and eventually the engine began belching black smoke [ very rich ] and eventually died. The headers are the only change made to my engine since racing earlier this year. Has anyone encountered similar problems with header installation and the elimination of catalytic converters? Thanks. Mark Dandurand - American Iron #5

tcrews
11-30-2003, 05:03 PM
Have you pulled the code yet to see what set off the 'check engine light'? You can go to Autozone and they'll pull it for free.

Guessing (since I don't know what code you have yet) it sounds like you could have an exhaust leak that would affect the front O2 sensor. If this is too far out of range it will put the car in "limp mode" and run extremely rich (black smoke out the tailpipes).

johnbasf
11-30-2003, 09:14 PM
Hey Mark and welcome. I told you Tom would have some insight.:thumbsup:

markdandurand
12-01-2003, 03:26 AM
Originally posted by tcrews
Have you pulled the code yet to see what set off the 'check engine light'? You can go to Autozone and they'll pull it for free.

Guessing (since I don't know what code you have yet) it sounds like you could have an exhaust leak that would affect the front O2 sensor. If this is too far out of range it will put the car in "limp mode" and run extremely rich (black smoke out the tailpipes).

Thanks Tom! I am borrowing some OBD@ analysis equipment next weekend to pull the codes. The check engine code light goes out when you cycle the master power switch [ so it is currently not on ]. I don't know if the fault codes can still be read at that point. I will be talking to autologic today to see if a new chip can be burned to bypass the O2 sensors completely. Thanks again ! Mark Dandurand

markdandurand
12-01-2003, 03:31 AM
Originally posted by johnbasf
Hey Mark and welcome. I told you Tom would have some insight.:thumbsup:

Thanks John. I will try and check the codes next weekend . Also, I plan to call autologic today [ at your suggestion ] to see if a new chip can be burned to bypass the O2 sensors entirely. Regards. Mark Dandurand

tcrews
12-01-2003, 08:09 AM
You might still be able to pull the codes.

I wouldn't try to bypass the front O2s as you could end up with a seriously hurt engine. While the O2 sensors are only narrow band, they can tell if the exhaust gas A/F ratio is too lean or too rich and make corrections accordingly. If the engine is too lean you could easily pop a piston.

Now the rear O2s do nothing other than monitor catalytic efficiency...so either MIL eliminators or disabling them through the autologic chip is fine. They do nothing to affect performance, they will only trigger the check engine light if they detect that your cats (or lack of) are failing.

markdandurand
12-01-2003, 08:16 AM
Thanks for the additional info ! Regards. Mark Dandurand

johnbasf
12-01-2003, 05:25 PM
Good post Tom. True Blue informed me that the front O2 sensors MUST stay.

markdandurand
12-01-2003, 06:26 PM
John, I ordered a new Autologic chip today [ 5 degrees timing advance- pretty conservative ] and purchased new O2 sensors for the front connection on the headers. The new chip will eliminate the need for the rear O2 sensors. I appreciate your help and suggestions here. Thanks. MAD