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Discussion Starter · #1 ·
Hi

i have jus installed a fabspeed headers wihout sportcats and also got the 02 spacers to keep the C.E.L off but the light came out on the 4th day. i had the foult deleted but its a bit bothering when u see it and aren't those spacers sposed to keep them off.
 

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Spacers did not work for me, and I have hi-flow cats in my headers. I'm not suprised they didn't work for you with no cats. As posted above, I think most folks with catless headers opt for a reflash so that the ecu will ignore the rear o2 sensors.
 

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O2 simulators are an option as well. I got mine from magnum tuning, you will need two of them and they are about $70 each.
 

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Spacers did not work for me, and I have hi-flow cats in my headers. I'm not suprised they didn't work for you with no cats. As posted above, I think most folks with catless headers opt for a reflash so that the ecu will ignore the rear o2 sensors.
I have Fabspeed headers with the hi flow cats, but no CEL. Weird the light came on for your setup.
 

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I have Fabspeed headers with the hi flow cats, but no CEL. Weird the light came on for your setup.
Not weird at all, 95+% of all Caymans/Boxster that install headers with either no cats or high flow cats will trip a check engine light eventually for cat warm-up failure. I'm not sure if I recall the codes exactly but something like P431 or something, I know that's in a past topic thread on this site. You can clear those codes with a $50 code reader/clearer, or you can simply flash your ECU so that you don't have the problem anymore. Spacers rarely (if ever) work, relocation sometimes works, and different fake sensors I have info on, I suppose they are sending a constant value within an acceptible range no matter what your exhaust is doing. That may or may not result in other issues later on.

If you decide to buy headers you should budget in a flash as well.
 

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... and different fake sensors I have info on, I suppose they are sending a constant value within an acceptible range no matter what your exhaust is doing. That may or may not result in other issues later on.
The simulators I installed are powered units. They have an adjustable resistance that you set to match the heater and the cat simulator is adjustable as well. It sends a wave and the voltage fluctuates in a similar fashion to an O2 sensor.

In the DME, the secondary O2 sensor data is simply compared to the primary O2 sensor data to ensure that the cats are working. They do not affect the fuel mixture, that is the function of the primary O2 sensor. If the data is not within parameters (bad cat or bad secondary o2 sensor) then the DME will kick into reduced performance fuel and timing curves.

So running with bad cats, bad o2 sensors or no secondary o2 sensors is much more of an issue than running good quality six wire o2 simulators in terms of long term issues.
 

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One of the errors I got with the spacers was related to 'dynamism' (or something like that). I assume this means the rear O2s did not respond quickly enough to changes. Based on this, I'm not sure a simulator would work with a 987.
 

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Not weird at all, 95+% of all Caymans/Boxster that install headers with either no cats or high flow cats will trip a check engine light eventually for cat warm-up failure. I'm not sure if I recall the codes exactly but something like P431 or something, I know that's in a past topic thread on this site. You can clear those codes with a $50 code reader/clearer, or you can simply flash your ECU so that you don't have the problem anymore. Spacers rarely (if ever) work, relocation sometimes works, and different fake sensors I have info on, I suppose they are sending a constant value within an acceptible range no matter what your exhaust is doing. That may or may not result in other issues later on.

If you decide to buy headers you should budget in a flash as well.
Interesting.. maybe I'm in the <5% group. Does the CEL go away once cats are warmed up? Or someone is likely to get the CEL once you've put some miles on the cats?
 

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All of the CELs pertaining to O2 sensor function from P0128 to P0167 will not turn off, you must clear the code.

Based on the comments in this thread you gents need a primer on how O2 sensors work and what they do.

Modern O2 sensors function explained OXYGEN SENSORS
 

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Discussion Starter · #12 ·
The simulators I installed are powered units. They have an adjustable resistance that you set to match the heater and the cat simulator is adjustable as well. It sends a wave and the voltage fluctuates in a similar fashion to an O2 sensor.

In the DME, the secondary O2 sensor data is simply compared to the primary O2 sensor data to ensure that the cats are working. They do not affect the fuel mixture, that is the function of the primary O2 sensor. If the data is not within parameters (bad cat or bad secondary o2 sensor) then the DME will kick into reduced performance fuel and timing curves.

So running with bad cats, bad o2 sensors or no secondary o2 sensors is much more of an issue than running good quality six wire o2 simulators in terms of long term issues.

I had a look at the simulator you are using i think its gonna be handy since i had the headers for a week and already got the C.E.L twice. But cant you solve this problem by an ecu tunning changing the input of the reading ?
 

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I had a look at the simulator you are using i think its gonna be handy since i had the headers for a week and already got the C.E.L twice. But cant you solve this problem by an ecu tunning changing the input of the reading ?
Yes the problem is solved with most quality ECU tunes that basically fool the ECU into thinking the values it is seeing from the secondary O2 sensor are fine, and thus no fault code is tripped. With the simulators they simulate the values that the ECU is looking for, what I mean by unknown long term effects is that there isn't enough of a history of them with Porsches to know what any negatives might be, for example a powered sensor that shorts out and sends a damaging pulse to your ECU. Is that possible? I don't know. Likely? again, not enough data to know. Sounds like a potentially lower cost solution than getting an ECU flash, but with an ECU flash you also get performance improvements which is why you put the headers on in the first place isn't it? I just think it is odd for people to install headers without also installing an ECU flash to get the most out of their performance improvements like headers, and especially fixing up that mid range torque dip that our cars have from the factory...
 

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Reflashing the ECU is preferable to the simulators but not everyone is in a situation where this can be done cheaply. In my case I have a tweaked DME and it would cost me a grand to get it done.
 

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Hey welcome on board, it's always good to have some more P-Cars from the ME area on here, and someone close by who likes mods. :cheers:

As you have the headers then it makes sense to get the ECU flashed as well, and there are quite a few local (Dubai mainly) options available.

Are you part of the Porsche Club UAE? If not why not ;)

Drop me a PM if you fancy meating up one time, or joining a drive I'm planning with a load of guys (Mainly P-Cars) up to Jebel Hafeet.

:cheers:
 

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Modern O2 sensors function explained OXYGEN SENSORS

Thanks for the link. Bringing back an old thread, but I'm curious if there is an alternative solution other than Softronic for race headers that won't leave OBDII trouble codes. I don't want to need to swap OEM headers back in for my state's/county's OBDII checks. I also want to avoid my computer from resorting to a lowered efficiency/performance mode with catless headers.
 

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Thanks for the link. Bringing back an old thread, but I'm curious if there is an alternative solution other than Softronic for race headers that won't leave OBDII trouble codes. I don't want to need to swap OEM headers back in for my state's/county's OBDII checks. I also want to avoid my computer from resorting to a lowered efficiency/performance mode with catless headers.
I think that sportcats are going to be the best solution.
 
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