Big problem after header and intake mod..
05-30-2008, 05:09 AM
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I ve put a performance air intake kit and de-cat headers with straight through exhaust to my 04 525i today.
Picked the car up from workshop,feels good and faster.After a few miles drive I stoped a while(about 2mins) with engine running.Soon the check engine light came up and engine started to flick a bit and exhaust sounds became weird,I can feel from the steering wheel about the engine flick.I turned the car off for about 30mins then restarted again.The CEL gone and the car back to normal but soon after I drive few miles then stoped the problem came up again..
Anyone done airintake and de-cat header+exhaust had this problem before?Do I need to do something with the ECU?
Picked the car up from workshop,feels good and faster.After a few miles drive I stoped a while(about 2mins) with engine running.Soon the check engine light came up and engine started to flick a bit and exhaust sounds became weird,I can feel from the steering wheel about the engine flick.I turned the car off for about 30mins then restarted again.The CEL gone and the car back to normal but soon after I drive few miles then stoped the problem came up again..
Anyone done airintake and de-cat header+exhaust had this problem before?Do I need to do something with the ECU?
05-30-2008, 05:43 AM
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Originally Posted by lintc0532' post='591522' date='May 30 2008, 08:09 AM
I ve put a performance air intake kit and de-cat headers with straight through exhaust to my 04 525i today.
Picked the car up from workshop,feels good and faster.After a few miles drive I stoped a while(about 2mins) with engine running.Soon the check engine light came up and engine started to flick a bit and exhaust sounds became weird,I can feel from the steering wheel about the engine flick.I turned the car off for about 30mins then restarted again.The CEL gone and the car back to normal but soon after I drive few miles then stoped the problem came up again..
Anyone done airintake and de-cat header+exhaust had this problem before?Do I need to do something with the ECU?
Picked the car up from workshop,feels good and faster.After a few miles drive I stoped a while(about 2mins) with engine running.Soon the check engine light came up and engine started to flick a bit and exhaust sounds became weird,I can feel from the steering wheel about the engine flick.I turned the car off for about 30mins then restarted again.The CEL gone and the car back to normal but soon after I drive few miles then stoped the problem came up again..
Anyone done airintake and de-cat header+exhaust had this problem before?Do I need to do something with the ECU?
05-30-2008, 07:20 AM
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Originally Posted by lintc0532' post='591522' date='May 30 2008, 02:09 PM
I ve put a performance air intake kit and de-cat headers with straight through exhaust to my 04 525i today.
Picked the car up from workshop,feels good and faster.After a few miles drive I stoped a while(about 2mins) with engine running.Soon the check engine light came up and engine started to flick a bit and exhaust sounds became weird,I can feel from the steering wheel about the engine flick.I turned the car off for about 30mins then restarted again.The CEL gone and the car back to normal but soon after I drive few miles then stoped the problem came up again..
Anyone done airintake and de-cat header+exhaust had this problem before?Do I need to do something with the ECU?
Picked the car up from workshop,feels good and faster.After a few miles drive I stoped a while(about 2mins) with engine running.Soon the check engine light came up and engine started to flick a bit and exhaust sounds became weird,I can feel from the steering wheel about the engine flick.I turned the car off for about 30mins then restarted again.The CEL gone and the car back to normal but soon after I drive few miles then stoped the problem came up again..
Anyone done airintake and de-cat header+exhaust had this problem before?Do I need to do something with the ECU?
Since you had header/cat work done there might be a leak making the sensor throw a lean mixture warning. Could be that as well.
05-31-2008, 08:42 AM
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If you delete cats without remapping your ECU, you are asking for trouble 
The lambda probes are possitioned before and after the cats, guess why?
Without cats the system will pick up faulty signals and throw the CEL.
The wierd exhaust note and flicking was probably the car getting into limp home mode, to save the cats (Which you do not have ) when reading error signals from the lambda probes.
The lambda probes are possitioned before and after the cats, guess why?
Without cats the system will pick up faulty signals and throw the CEL.
The wierd exhaust note and flicking was probably the car getting into limp home mode, to save the cats (Which you do not have
) when reading error signals from the lambda probes.
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