CHIP? 02 sensor issues. Anyone ever ran across this? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

mn box s · 01-31-2008, 11:57 PM

I replaced my entire exhaust with S.S. duloboz and fabspeed. I need to get some software to get the car running correctly. Im throwing codes because my fabspeed test pipe 86ed my rear o2 sensors so now Im running two instead of four 02s I bought four new and installed only two due to the fact that there were only two bungs (on headers.) Obviously Im throwing CEL codes for o2. I should be able to get away running the front two only because they are (i believe) the ones that read the air/fuel mix? Im thinking of welding in two new bungs but I dont really want to. Also if I was to do that Id need some o2 extention wires I heard that mustang ones work??? What I really want to know is if a software upgrade (chip) you could program the two rears out? Please help, thank you! thank you!

dcporsche99 · 02-01-2008, 12:16 AM

Sorry to hear about your O2 sensor issue. I think this was discussed somewhere before. However, I haven't heard of a software upgrade deleting the downpipe 02 sensors.

Hmmm,....I'm interested to know what others think about it.

In the meantime, perhaps you should try doing a search.

Keep us posted!

mn box s · 02-01-2008, 12:38 AM

Well you might have read a similar post from my self a year ago. I got pretty lazy the past year and the car runs quite well considering except at idle and fast high speed shifts there is a lag I guess I shift too fast (pause in power band). I didnt get to much help last year I found a local porsche performance shop that said they might beable to do something but I was looking for a back up answer first. So if anyone can help thanky thank you.

edevlin · 02-01-2008, 01:20 AM

I had similar issues chaseing error codes when I went to headers and high flow cats. Ended up replacing both cats and lots of sensors. Take care if extending the wires for the cats, as they appear to be sensitive to resistance of wire and how they are connected.

My car is also chipped and I asked the folks who wrote the chip about changing the threshold level that was triggering the sensors CEL. I think he said mechanics could get in a lot of trouble attempting that, as you are messing with what constitutes legal emissions levels. I think my exhaust was fussy to dial in because the TTP headers did not come with any bungs (you can see a photo at my Boxster site link below my signature).

When adding bungs on a modified exhaust seems it seems like care must be taken on bung placement both how far along the exhaust stream and height of sensor tip in the exhaust stream. And as I said above how the wire for the rear sensor is extended. It funny, some folks seem to have no problem when they try the procedure, other unfortunate souls like me end messing around with it quite a bit, it was 6 months before I got it right. On the up side, it sure makes me appreciate that the car is now running great and no CEL's.....

Ed

:dance:

shaman1204 · 02-01-2008, 05:58 AM

Check out this thread:

http://986forum.com/forums/showthread.php?t=14359&highlight=specs

SRQBoxster could probably chime in here, he deleted two o2 sensors when he installed headers and then re-flashed the ECU to Euro specs that only look for two sensors. I guess the problem would be finding a place that could or would do that for you.

Tool Pants · 02-01-2008, 07:05 AM

You need the sensor before the cat. The sensor after the cat is because of the EPA. By having a sensor before AND after the cat the cat efficiency can be determined, thanks to the EPA. This is why ROW 986s do not have as many sensors as US/Canada cars.

There are oxygen sensor simulators you can buy.

The other thing you might try is to leave the sensor after the cat still connected to the electrical connector, but the sensor is not screwed into the exhaust as you do not have a bung, and just leave the sensor hanging in air.

I tried this on my 2.5. I did get fault codes when I checked with a PST2, but the check engine light did not come on.

porsche986spyder · 02-01-2008, 10:16 AM

Quote:

Originally Posted by shaman1204

Check out this thread:

http://986forum.com/forums/showthread.php?t=14359&highlight=specs

SRQBoxster could probably chime in here, he deleted two o2 sensors when he installed headers and then re-flashed the ECU to Euro specs that only look for two sensors. I guess the problem would be finding a place that could or would do that for you.

I remember asking about this too. It seems like all the guy did that re programed his ECU was set him up with the early 97-99, 2.5Ltr spec setting which only has 2 cats instead of 4, but by doing that, you really are not utilizing the 00-04, 2.7Ltr engine. Seems like the wrong way to reprogram the ECU just to keep your cells from coming on.

blue2000s · 02-01-2008, 10:23 AM

You can also try rewiring the rear O2 wiring to trick the computer into thinking that it's seeing a good O2 sensor. This is written for a Mitsubishi, but the cabling is the same for any car (although wire colors may be different).

http://www.vfaq.com/mods/O2bypass.html

steve00s · 02-01-2008, 10:24 AM

I do not believe your CEL's are caused by the removal of the secondary cats. Those are downstream from the sensors and should not result in CEL's. The deloboz header has only one O2 bung per header (positioned towards the rear of the header), if I am not mistaken, and this is probably what is causing the problem. You could try having another bung welded towards the front. Maxspeed sells headers on Ebay and you can see from the pictures where the placement of the bungs are (they have two bungs per header). You can also puchase an extender piece that screws into the bung (put in the second bung) and pulls the sensor back out of the airflow slightly. These sell for about $20.

porsche986spyder · 02-01-2008, 11:56 AM

Quote:

Originally Posted by steve00s

I do not believe your CEL's are caused by the removal of the secondary cats. Those are downstream from the sensors and should not result in CEL's. The deloboz header has only one O2 bung per header (positioned towards the rear of the header), if I am not mistaken, and this is probably what is causing the problem. You could try having another bung welded towards the front. Maxspeed sells headers on Ebay and you can see from the pictures where the placement of the bungs are (they have two bungs per header). You can also puchase an extender piece that screws into the bung (put in the second bung) and pulls the sensor back out of the airflow slightly. These sell for about $20.

Yep, that's really the only way to go unless you buy some expensive High-flow Cats that are built into the headers, like the Fabspeed ones or leave the cats on the down pipes only and delete the first set in the headers, but you can't delete all 4 without getting the cell light to coming on. Unless you relocate or weld on the extra bung wholes. Sound kind of tricky.

tholyoak · 02-01-2008, 01:19 PM

You guys need to listen to tool pants. The second sensor is there to determine cat efficiency. If you run the OBDII program in the ECU you need at least 2 cats and 4 O2 sensors or somehow do a band-aid solution into tricking the ECU into thinking that the cat is there by using a false signal for the after cat sensor. The same can be accomplished by running an ROW ECU program as these cars only use a pre-cat sensor for mixture determination and don't have an after cat sensor for Cat efficiency.

Todd

porsche986spyder · 02-01-2008, 02:57 PM

Quote:

Originally Posted by tholyoak

You guys need to listen to tool pants. The second sensor is there to determine cat efficiency. If you run the OBDII program in the ECU you need at least 2 cats and 4 O2 sensors or somehow do a band-aid solution into tricking the ECU into thinking that the cat is there by using a false signal for the after cat sensor. The same can be accomplished by running an ROW ECU program as these cars only use a pre-cat sensor for mixture determination and don't have an after cat sensor for Cat efficiency.

Todd

Is the ROW ECU the European Motec program? That makes sense. But how do you get a hold of it and find someone to do it for you. Then after all that is done you still may not pass emissions to drive it on the street.

choeglund · 02-01-2008, 04:17 PM

Softronic ECU flash will fake the value that the ECU reads in the secondary O2 sensors. I'm not sure if the secondary O2 sensors can be completely removed, however. Go here and call the number: www.softronic.us Talk to Scott and he will tell if you can eliminate O2 sensors entirely or if you need an additional bung somewhere. Also, there is lots of info on Softronic flash over at caymanclub.net. Search on snap-flash and look for the thread that's 20+ pages long. BTW, I have no affiliation with Softronic. Good Luck.

RandallNeighbour · 02-01-2008, 04:49 PM

I believe Turbowerx in Austin, TX is coming out with a chip that eliminates CE codes from sensors.

They're developing a set of sport cats for 986's (2.5, 2.7) and wanted to release the chip with the product.

mn box s · 02-03-2008, 08:39 PM

Thanks to all who replied it seems that this time I have a few leeds that I didnt last year. You all may have herd of a guy by the name of Jesse Ventura. yep he was the Gov. of MN and a porsche fanatic. Yes I did vote for him and my main reason why he followed through with. He completely elimenated MN's auto air testing. He even sold all of the facilities and gave the money to MN's people with a check. What a %#$! cool Governor! So just about all of the cars I have owned the cats are removed. Yes I have no cats on my car so ......so. Ha who cares about reflashing in MN. I feel sorry for all of the People of CA, too many people! Soon you will have emission undies! Anyway Im going to give some of these avenues a try and if all else fails I can tig weld and you helped me find a correct placement, thank you, thank you! my box is an S so a 2.7 or 2.5 flash is not what Im looking for. I'm a little afraid of a euro flash too.

SRQ Boxster · 02-04-2008, 03:06 PM

Quote:

Originally Posted by porsche986spyder

Is the ROW ECU the European Motec program? That makes sense. But how do you get a hold of it and find someone to do it for you. Then after all that is done you still may not pass emissions to drive it on the street.

Sorry guys, I didn't see this post untill I was sent a PM. Just a quick recap of my car, set-up and what is working for me. I have an '02 S, EVO intake, single-bung O2 headers, Stebro bypass pipes and Stebro Sport mufflers. My ECU was programmed to 3.2 RoW specs to eliminate the OBDII O2 sensors. I have no running issues or CEL with this modification. My state (FL) does not have State inspections to police emission control devices, however this does violate Fed. laws for highway driven cars (mine is for track use). A local tunner here in Sarasota did my ECU update (Renn Haus). I am not a spokesman or rep. for them, only a customer. They can be contacted for anyone looking for specific info. on ECU programming. Hope this hepls.