Sounds like a Durametric would be a worthwhile investment. I got mine (haven't had to use it yet), the non-pro version that can only be used for three cars, on craiglist for $170 with 2 car slots left. If you ever sell your car you'll probably be able to recoup at least half of the Durametric's cost. Good value IMO.

I've been eye-balling the Durametric for a little while now. Seems like a really useful tool.

I stuffed my big head under the Box last night looking for a ground strap I could clean contacts on. Couldn't find it? Maybe it's on the topside? I'll check that part soon. I've read here and there about ground gremlins causing all sorts of bizzare issues.

AOS tests good (Oil cap test) and is only 4 years old. Never smokes, ever that I've ever seen or could smell. But running a little rich. Could still be 3 bad O2's I guess? It doesn't make sense I couldn't test them, only the one I replaced could I test through the software.

I added a ground strap last night from the tranny to the chassis. I didn't clear codes or test drive until I went to work this morning. I should have cleared the codes (duh). Not that I think I fixed anything, but with each change I should test to see if it's corrected my large swath of codes.

I did notice the car seems to be a little smoother now. Especially when it comes to very lightly on-off throttle. It's not "jerky" anymore. Not like it was, but it's smoother.

So the ground strap did good, just how much I still have to find out.

documentation
 

Dan,

Go to here for essential documentation:

http://www.digital-kaos.co.uk/forums/f104/porsche-poses-2-42-install-cd-46838/

I couldn't get the system to install, but once the zip archives are unzipped, you can save all the English (EN) pdf's that are OBD2 related which contain troubleshooting information for all the codes -- stop searching in the dark and wasting your time!!!

BTW, don't ever clean a MAF sensor with soap/water -- CRC makes a spray cleaner for MAFs.

Regards,

paul

Very cool, thanks Paul.

I wound up replaced the MAF after my "cleaning" which truly was nothing more than water, and not much of that either.

It wasn't the MAF at all.

I'm still hopeful the codes aren't being caused by bad wiring or bad DME.

Since I can test the O2 I replaced, but none of the others, I did order up 3 more from GRP. They should be here by the weekend. I know, I know, shouldn't just throw parts at it. But I think it's a good set of variables to eliminate.

I'll keep the updates coming. - Dan

Bad/corroded wiring/connectors have their share of causing CELs to come on and should be inspected/tested with a good digital volt/amp/ohm meter (at least a 10 Mega ohm input impedance).

Regards,
paul...

Replaced the other 3 O2's today. Noticed the Bosch have shorter wires and better connectors.

CEL was cleared and after 60 minutes of driving didn't come back on. Won't say that I solved the issues yet. But so far so good.

CEL did come back on today, P0403, none of the original codes were present. Cleared just for giggles, took about an hour of driving and same P0403 code returned. I'll consider this issue closed now. Hopefully it'll make a good reference for someone else in the future.

On to the next code! :)

The P0403 is a generic code for an EGR system, and I didn't know that these engines had an EGR valve. Maybe someone else knows.

Regards,
paul...

With my Box having 103k on the clock and pretty much everything original, I plan to replace the following which will hopefully resolve the latest CEL:

993-113-250-03 - Crank case check-vent valve
996-113-245-01 - Change over vavle for air injection
993-113-245-01 - Cut off valve for air injection

All those will be around $200 and if they don't solve it:

996-605-201-01 - Purge vavle for fuel vapor canistor

And if I get desperate:

996-606-160-01 - Idle air control valve - like $300 or so.

The change over valve has an electrical connection on it, so I am hoping that is what is causing the CEL. We'll see. I'll post back results here.

Before I order anything though, I'm going to pull the lid this weekend and check hoses again, make sure things are clear and actually see if I have any of the above listed EGR related parts on my Box. It's a 97', so I can see Porsche using some 993 parts I guess?

Making progress!

P0403 is a code I have never seen on a Porsche :confused: . Are you sure?

Ultimately it is your car and your dough but if it was my dough I would verify the code, get a description of the fault involved and use the process of elimination to find and fix the problem. There are good online resources to help. If you are not comfortable doing this it might be money well spent to take your car to a qualified Porsche tech for a diagnosis. Otherwise you could blindly change out $2000 in parts and miss the problem completely... or end up with more error codes :o . It happens.

You got me scratching my head now. Pretty sure it was P0403, but that was using the local parts store OBD2 reader. I wouldn't have ordered any parts before really checking things as planned this weekend. I haven't hooked it up to my laptop at home yet. Maybe I'll do that tonight and make sure I'm reading the correct code.

I'll report back. - Dan

Derrrr, it's P0430, not 403. Just call me dyslex,,,,,dislexs,,,,,dys,,,,,oh never mind. :)

Not much research to do here other than replace the cat. Time to shop and probably just get both. I'm sure the left isn't far behind.

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For a P0430:

Possible fault cause
♦ Oxygen sensor ahead of and after TWC exchanged
♦ Valve lift fault
♦ Aged oxygen sensor after TWC
♦ TWC faulty

Regards,
paul...

Hey Yellowstonepart,

Porsche 戲汽車沒有柴油機 !

再見,

paul...

Paulv,

It's just a guess on my part, but after replacing all 4 O2's now and all the other CEL's gone with only the P0430 present. I can now test and pass all 4 O2's so I am hoping it's just a bad Cat. I would assume so since the PO ran with faulty O2's for almost 3 years! I'm sure the Right Cat is clogged (ruined) and the left isn't far behind.

I found a pair of good low mile cats for $350 shipped to me. The 4 O2's, MAF, 2 front tires and lots of other little maint items have left my Porsche fund a little dry. Gotta water the money tree for a bit. Meanwhile, I'm trying not to drive the car much.

Upates to come....when I get some more money. :D

That code is for Bank 2 which is the driver's side (Bank 1 has the #1 cylinder in it and would have the P0420 code). If you have a buddy who owns or has access to an exhaust gas analyzer, you could measure all the gases (NOx, CO, HC, O2, CO2) before and after the Cat to prove it bad (or good). BTW, running with bad O2 sensors will make the car perform lousy as well as destroy the cats. Attached a little tutorial about exhaust gases.

Regards,
paul...

This was a recent purchase for me (not my first Box though). It runs great and had no real notable change when the O2's were replaced other than the CEL's didn't come back. So there might have been a short in one of them? I didn't bother to test them after replacement.

420, right, sorry I was thinking engine orientation backwards, I should know that. I don't know anyone anymore that does the analyzing, but I'm sure I could track down a local shop that'd do it for a couple of bucks. Probably worth it. Why replace a cat when I may not need to?

Other thing I was going to try this weekend was swap O2's from side to side. See if I get a P0420 instead of a P0430. If I do, then I know one of my new O2's is probably bad.

So, still things to check. Good side is codes are different and there's only one now.

You didn't mention it but I'm assuming that you will be swapping the "after cat" O2 sensors from side to side, as these are the ones whose signal is compared to the "pre-cat" sensor to determine cat efficiency (a required readiness monitor under OBD2 mandates) and sets the P0420/30 code when the efficiency falls below a predetermined limit.

Regards,
paul...