Niels Jørgensen

This may be a silly question, but I'm thinking of installing a few gadgets to help me keep an eye on things. In particular, the fuel pressue gauge and ARM1 fuel/air ratio meter from 928 specialists.

The ARM1 uses the existing O2 sensor, but since my car is an early 87 S4 with no cat, I'm not sure I even got one (I somehow got the impression (or was told, can't remember) that the O2 sensor is only present on cars that have a cat, is this true? If so, do I just buy one and how/where is it mounted?

TIA

Athenian.

You should have an O2 sensor even if your car has no cat (ie Euro cars have no cats but they have O2 sensors)....You should be able to have a muffler shop thread an opening, right after the Y downpipe and retrofit an O2 sensor. I know the '87 S4 cars have a 3-wire O2 sensor.

I hope this helps - VK

Niels Jørgensen

Thanks... I'll assume there is one then

Greg86andahalf

My cat-bypass pipe from 928 Specialists supports a 02 sensor. I saw the same 02 mounting hole on a Ott X-over cat bypass this weekend.

DaveW

Not all euro cars have o2 sensors - neither of mine do.

Dave

GoRideSno

Niels,
Split second sells the ARM1 in a kit that includes an O2 Sensor. <a href="http://www.splitsec.com/" target="_blank">I think this link will go right to it.</a> There are good ARM1 Installation instructions on Tony's site.
HTH
Andy K

Niels Jørgensen

Ok, since there are obviously various opinions on whether or not an 87 S4 without cat has an O2 sensor or not <img border="0" alt="[oops]" title="" src="graemlins/oops.gif" /> , I have another question: Is there a quick way to check for an O2 sensor or do I have to get under the car?

Mike LaBranche

Well... the easiest way to check is to slide under the pass. side, look at the top of the Y portion of the bypass. You will see a cylinder about 1" in diameter, say 2.5-3" in height with 1,2, or 3 wires running from top into pass. footwell, connecting to wires near fuse/relay panel. I'd say chances are 90% + you have an O2 sensor.

Athenian.

Gens - I have read in several pubs that Porsche started manufacturing ALL 1987 928 S4 models onward with cats and O2 sensors. That includes European, ROW and of course US cars. Prior to 1987 that was not the case. As we know, pre-1987 Euro cars had no cats (just a pre-muffler in its place or a staight pipe). My '84 has a small muffler in the place of the Cat and an O2 sensor installed. Other pre-87 cars may or may not have an O2 sensor installed. Or possibly installed by the factory and removed by the PO.

Whichever the case, Porsche decided that starting with '87 model year to produce all 928 cars having the same HP output worldwide to comply with stricter emissions standards in Germany as well. Hence the universal use of catalytic convertors and O2 sensors in all S4 928s onward.

I hope this helps to clear the smoke on Niels' original question on this '87 car.

VK