goingboeing737

I have traced down ONE of the wires that looks questionable.

It is the 02 sensor.

It comes off the sensor (very thin black wire) it seems to have a bare spot on it from rubbing/vibration on the lower part of the bell housing. Then it goes into a rubber plug that looks like some kind of capacitor/resistor then comes out into a heavier gauge green wire. Right where the green wire comes out was another kind of shield which was mounted to the firewall. This shielding has just broke off (looks like wood, but is plastic). Also, the green wire at the capacitor/resistor looking thing is about to break.

The heavy green wire goes into a wiring harness which has a 2 wire molex plug that is not connected to anything.

Looking in the Haynes Manual (pg 203) I think the non used 2 wire plug is for "oxygen sensor heating" (Calif. only).

Could this be causing my problem? Somehow giving false reading to DME?

I will fix the bare spot, don't know how to fix the heavy green wire where it is about to break.

02 sensor wiring / green wire out of resistor thing

goingboeing737

added picture:

02 sensor wire

The other shielding (that just broke off) was just where the green wire comes out of the black thing.

goingboeing737

Well I broke the wire (lage green one) going into the black connector. It was hanging one by one or two strands.

So now I basicly don't have a functioning 02 sensor.

Gonna call and see if its a replacable Porsche part or try a parts yard if not. The PET does not show it as a part # or any place where it connects, just goes into harness under the hood.

Red1

James, you looking for where the O2 sensor plugs into the harness? I've gotten a little lost trying to keep up with you.

I think it's different for the early cars (yours), but the later cars O2 sensor plugs into the harness between the intake manifold and the firewall. (I never wanted to splice wires, so I've always spent way too much money and bought plug-in replacement sensors.) If you're going to splice a new sensor to the old plug, I'd try to minimize the length of the old wire. Some of your wiring is getting pretty brittle.

When you go to put a new sensor in, go from underneath, and tape the new wire to the old one. Then you can just pull the old wire up from above, and the new wire will thread through the engine bay no sweat. I keep string in the garage for those occaisions when I'm removing wires but don't have the new ones ready yet. Makes threading wires and hoses a breeze.

Somebody mentioned warming the car up to make the O2 sensor easier to remove. That's a good idea. I've had a couple that were pretty stubborn.

goingboeing737

Replace 02 sensor about 8 months ago. It is not the sensor, but rather the wire that goes TO it.

Just got off the phone with dealer, As I suspected from looking at the PET, there is no plug connection for this wire. It is part of the DME harness.

Strange setup, Thin black wire (24 gauge?) goes into this black rubber/plastic piece and comes out the other side a larger green (14 gauge?) wire. I don't know the function of this "black rubber/plastic" thing, resistor, capacitor???

So,,,, I just drove it around the block without the 02 sensor hooked up, and not much change. Still dies, but starts up after I pull over.

I don't know/think the 02 sensor wire is really related to the stalling problem, it is just another one of those things I gotta get fixed.

Red1

You need an old priest, and a young priest.....


-or-

Hey, we're not that far from New Orleans, maybe we can get a voudon bokor to pull a little voodooo magic on that thing.

goingboeing737

Well she aint stalling.

I replaced the Pressure Damper on the fuel rail. I had the ones from my old cracked rail. This has been suspect since I put the new(used)rail on. I just drove about 5 miles with no stall.

Does this make sense? or is it just fooling me???

Red1

Makes more sense than blood sacrifices.

Just trying to keep your spirits up.

Matt H

It does make sense. The car will fail emissions without the 02 and might set a trouble light (not sure if the earlies had this). Just solder some new wire in place.
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goingboeing737

But only slightly more sense..right?

The blood letting was during the re-carpeting,,,quite a few sharp things under there,,many red cells gave it up during the process.

Maybe it wants more.......

Red1

It's a porsche, it always wants more.

More money
More blood
More time
More garage space
More more more

Matt H

So what you are saying is the Porsches are like women >) No offense!
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Kevin Baker

FPD can cause that "stall" b/c when the FPD fails it will allow a "too high" fuel pressure, and the DME or injectors will not fire, when the car stalls the excess pressure bleeds back to the tank and that would let the injectors fire.

To check the old FPD, smell the vacuum end of it or see if there is fuel in it. When the diaphram (sp) goes bad it will leak fuel into the vaccuum side.

Here again I have both a FPD and a FPR that I took off, when I was chasing my problem the both hold vac. and dont have fuel, so if you'd like to swap em to test just give me a yell.

Red1

I think we go digging around that garage of Kevin's, we may find Jimmy Hoffa buried in there somewhere.

Get that teener out of there, and you won't know what to do with all the space.

Kevin Baker

Hey, hey, now...I know "Baker" doesn't sound Italian, but my fraternal grandmother was "Gallo" before she got married (I think remarried after my "natural" grandfather died). Lots of family secrets hiding here (pun intended) we moved from New York. So while Mr. Hoffa MAY not be in my garage...people I'm related to, know.