Check Engine Light

[JamesUK]

Hello all, Sorry for dumping this out there but this is my first post, please forgive me.
I have just bought a 96 993 C2 with 95k on the clock. I had it checked over by my local Porsche dealer, and apart from a few known faults (Power seats don't move for/aft) it was given a clean bill of health.
However yesterday I went for a drive with my wife (20 miles after passing of smog) and the CEL came on. O joy (why does this always happen with your wife in the car)!

Now I did a little bit of reading last night to see what this may be about and only seamed to find info on the SAI issue. However I did see someone saying there are up to 140 reason this light can come on.

I believe my first port of call should be to find the fault code but how should I do this? And secondly once I have the code can I type it in here to find a fix?

Yesterday was only short drives over town, and I let the engine warm up before driving could these conditions helped bring this dark cloud over my life?

Please help

[Oh Haha]

Stop by your local Autozone and have them read the code. You can't start diagnosing anything until you figure that out. Post the code here so we can help you even more.

Good luck and I hope it's nothing serious.

[JamesUK]

Thanks Wayne, All lost at sea over here in the US. Would know where to go back in the UK. Autozone it is, I did find a thing online, CarMD, That clams to be able to read codes maybe I'll look into that as well.

[Oh Haha]

Welcome to Pelican AND the US, in that case.

Is the car running ok? No funny sounds/smells?

[JamesUK]

Thank you!

Yes she run's fine, but what all this Porsche stuff is a bit new to me. What are the sounds and smells I should be looking out for?

[Oh Haha]

Burning rubber/electrical bits smells come to mind. Is the car idling normally, running strong in all gears?

Any clunking/loud tapping or rattling sounds coming from the engine?

The air-cooled engines have a unique smell, not unlike hot oil.

The CEL could indicate something as simple as the gas cap being loose to a vaccum leak.

Get the code and we'll help you get her fixed up.

[johnnywishbone]

pm sent

[JamesUK]

No, No clunking/etc it does have that oil like smell and sadly its not the gas cap, I just went and tried it, bummer!

Watch this space for a code.

[JamesUK]

Ok so I bought a OBD 2 scanner and this is what I have:
P0300,0304/0305/0306

MIL ON, Misfire (see above!) Fuel,Comp,Catalyst,Evap,Sec Air,O2 Snsr and last but by no means lest O2 Htr.

Now what strikes me about the misfire is that the car just had new plugs, leads, distributor caps and rotors back in mid June. She ideals at 900rpm give or take. Also she just passed CA Smog on the 2/20/2011.

Over to you guys, thanks.

[Oh Haha]

Ok, now we can get on with diagnosis. P0300 can be triggered by many things but let's start with the basics.

Seeing as how it just passed smog I still wouldn't be too concerned about it being a major issue.

Look around your intake for any obvious air leaks. Check that the Mass Air Flow sensor is securely in place, all hose connections are tight, and the sir filter cover is secured properly.


One more question--How fresh is the fuel? Was it sitting for long before your purchase?


I'm going to stop there and let the guys that have 993s help you further.


Wishing you well in getting it back to normal.

[JamesUK]

Wayne, Thanks so much, I'll go look at those things now.

I hope some 993 guys pick up the baton.

[Oh Haha]

You should consider joining Rennlist as well. They have a great bunch of guys that really know the 993. Apparently, you DON'T need to join to search.


I found several threads but I can't copy the link to here.

A post I pulled from a thread.-
A F-L-A-S-H-I-N-G CEL light is usually triggered by an engine misfire. The FLASHING is literally to 'grab' your attention - as this is 'serious' and pretty much seals the deal that you need to STOP and SHUT THE ENGINE DOWN.

When the CEL comes on - and stays on - you CAN drive it. You have a choice of:

i) Letting the ECU 'solve the problem all by its lonesome' (which it will do if it 'senses' that the condition(s) that triggered the 'error' do NOT occur over several subsequent drive cycles). READ: The CEL will switch off all by itself.
ii) Having the code read (OBD 'reader') and the condition 'cleared'. This, as we all know, will RESET all those pesky 'readiness monitors' as well as turning the CEL light off.

It REALLY is worth 'investing' in a decent OBD code reader so that YOU can decide whether this is a 'transient error' (e.g. loose gas cap) or something that infers 'maintenance required'.

[DW SD]

James,
Looks like one cylinder bank may be misfiring (4, 5, 6) side. Is vibration not noticeable from the misfires?

I'm giving some thought to why a whole bank of cylinders may misfire. The two coils fire both sides. Maybe a bad O2 sensor on the the 4,5,6 side? Maybe a vacuum leak where the intake plenum is joined together and primarily affecting the 4/5/6 side?

I might also call the shop that did the PPI. They hopefully, would have some good insights.

Doug

[JamesUK]

Doug,

Thanks I talked to the last guy who did a lot of work on the car and cleared the OBD readings due to the advice that if it was a real issue the light would come back on. As you say because of the coils how could it be on side. Anyway the car runs fine and no sine of the light coming back yet. If you look at the earlier post one of the
MIL ON, Misfire (see above!) Fuel,Comp,Catalyst,Evap,Sec Air,O2 Snsr and last but by no means lest O2 Htr.
You can see that it did call out the O2 Sensor. How hard/expensive is it to replace these?

Thanks James