Now im getting frustrated! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

RandallNeighbour · 02-13-2006, 07:22 PM

Bad 02 sensors can throw off the MAF and give funky readings that are very hard to diagnose. I had a bad sensor that made the PST tool indicate that the MAF was malfunctioning. My mechanic swapped the failing sensor with an old one he had lying around his shop and the MAF readings started looking good again.

How many miles do you have on your boxster and what year is it?

blinkwatt · 02-13-2006, 07:30 PM

53k on a 99. I had a quick peak under the car and located all four o2 sensors. Now the question is how hard are they to change?

RandallNeighbour · 02-13-2006, 08:06 PM

super easy and you're certainly due. They're to be changed at 60k.

www.oxygensensors.com

OEM Bosch sensors with the right connectors for $119 each or something close to that. If you have a floor jack, you can do it with normal tools and some grunting and at least one bloody knuckle in 45 minutes.

A $10 02 sensor offset slotted socket made it really easy for me.

Change out all four (required) plus your MAF and you should be CE light free for a long, long time. Plus, you'll get better fuel economy and possibly more power if you disconnect your battery afterwards for about a half hour or less. (this makes the DME recalibrate the system, which includes rough idling for a little while).

blinkwatt · 02-13-2006, 08:17 PM

If I do not have the funds for all four is it possible that I run a month or two with 3 old and one brand new? Is it possible that just the o2 sensor wiring should be check ed to make nothing came loose? Does anyone have any directions on accessing the o2 sensors,more specifically taking them off and reconnecting?

RandallNeighbour · 02-13-2006, 08:23 PM

One brand new one will be overly sensitive and the others dull, making for lousy fuel economy, really bad performance, more CE lights and who knows what. I guess it's possible, but I've been warned over and over by my own mechanic and people on lists everywhere not to do it.

Drive the car "as is" if you can, grit your teeth every time you see that CE light, and save up enough to swap out all four asap.

Thank goodness you don't have to change these out all the time, huh?

RandallNeighbour · 02-13-2006, 08:25 PM

Taking them off is easy. Unscrew them.

But, you have to unplug them first, and this is done by carefully putting the blade of a flathead screwdriver into the locking side of the connector and twisting to get it to pop the male part out of the receptacle. It really is quite easy, and when you get your new ones you'll see how to open them up and you'll say "duh, that's no big deal"

blinkwatt · 02-13-2006, 08:48 PM

I can physically see the sensors but where do the wires run to?

RandallNeighbour · 02-13-2006, 08:57 PM

Up to where they plug in! On the back ones, you'll have to peel back the heat shield to see the plugs. On the front ones, there is no heat shield and you should be able to see the plugs with a flashlight.

xclusivecar · 02-13-2006, 08:57 PM

Swap all 4!!!!!!! Not doing so will keep the CEL on. Trust me...I went through this very recently.