74carreraturbo

I had my car serviced for the A/C , an oil change and the cat bypass pipe being done last week. I get the car back and immedieately notice a few things I feel are odd:


- sometimes when the car has sat for an hour and i'll fire it up, the idle will hunt from 700-1200RPM for 30 seconds before settling in.

-I cant put the AC on now because every time i do and push in the clutch, the car stalls. It didnt do this before I had it serviced(needed a recharge), but now seems to.

- this is the one i'm suspecting is the culprit of both problems but i'm not sure. I smell oil alot more in the car when i'm driving around(not a bunch, just whiffs).. Never did before and if i go behind the car i smell nothing, it's really only inside. Also, i noticed my oil level when idling and warm is over the 3/4 mark but not at the top. Is it possible the oil is overfilled and messing with everything?

Any help would be appreciated as i'd like to enjoy my AC without having to restart the car all the time! The car does have a light flywheel BTW, so i'm sure its part of the issue!

Rob

JasonAndreas

And you didn't have the stalling problem before all the maintenance work? Did the shop install the oxygen sensor into the cat-bypass?

74carreraturbo

yes, they put a new oxygen sensor in as well. The car would stall very rarely before this, now it will stall more often when really cold or every single time when the AC is on. Once the car warms up for a just a minute or two of driving it wont stall. However, if the AC is on it could be completely warm and it will just die coming to stoplights when i push the clutch in.

MisterRisky

Prior to the recharge was the AC working at all? I am wondering if the AC system was low enough that the compressor was not running or was not producing a load when running. Now that you have AC system pressure you get enough load from the AC that it causes stalling.

I don't have the LW Flywheel but I thought I read that those who do have it always have AC with idle problems. Can anyone confirm this?

993c2cab

When I installed the cat bypass in my 993 I noticed the smell of oil at stop lights, and a pillow that was in the passenger footwell reaked of oily smell. I think it's the nature of the beast with the bypass imho.

964russ

My car allso stalls sumtimes with the AC on. Ive been told the DME is supposed to up the revs when the AC is swiched on, to handle the power drain from the pump.
I allso wont this fixin. Does anyone know anymore?

altarchsa

I would check the sensor connection in the engine compartment. I noticed when I replaced mine, and again when installing the engine after major work, that the connector can be tricky to mate up thoroughly with that offset design. Also, not likely but a new sensor can be bad.

964russ

Where is this sensor connection?
Thanks again......

J richard

I have found that the cat bypass does a few things, sound is great, but the cat really does it job in reducing emissions, when you run the bypass the exhaust smell is much more pronounced. I had a bypass with the o2 sensor bung that was so deep the sensor didn't protrude into the exhaust, and the stalling issue was much more pronounced, I got out the angle grinder and shortened it up and it seemed to help. So are you using the same o2 sensor?

The issue with the LWF seems to be that the DME can't keep up with the quicker engine rpm drop, so it makes sense to me that anything that reduces backpressure, like a free flowing exhaust, open intake, maf etc, just augments the problem. Anything that adds a load on the motor will quicken the drop to idle and add to the stalling problem, mine is most pronounced with the AC on and the Lights on, with both ac and alternator load. At least that's my story and I'm stickin to it...

Steve Wong has a chip for this you might give him a call.

altarchsa

It's in the left front corner of the engine compartment, just inside the point the wire goes through the sheet metal and below the auxilliary fan. The connector has three contacts, I believe, but it has about a 1/4" deep offset in half the base of each half of the connector which prevents the wires from being connected incorrectly. That offset has to alligned from one side of the connector to the other and requires a little finessing to get the two sides pushed together.

Good luck.

JasonAndreas

If you find that the O2 sensor is connected properly ask your mechanic if he installed an O2 sensor that was OE Porsche (in a box from PCNA), OEM Bosch or generic/universal. If it was anything other than OE Porsche ask them if they still have the old sensor. If they do have it, before you try anything else including going with a custom chip, reinstall the old O2 sensor into the cat-bypass. I know that it is possible for the stock software with a LWF, cat-bypass & OE sensor to work 99% of the time without stalling. And if your problem is an aftermarket sensor (Bosch or otherwise) that could finally explain (one of) the major differences people have been seeing over the years. I'm actually tempted to go out and try several different O2 sensors. I think it might be the one thing we didn't check when trying different LWF software solutions.