996 Turbo Intermittent fault

[Stuggart441]

Over the last 6 months my 2002 996 Turbo has an intermittent fault, a light comes on the dash saying "check engine, drive to workshop". Occasionally it flashes but then goes out. I tried AMD in Lakeside who have serviced it for the last 2 years and they replaced the coil packs but the light still came on intermittently. They have an association with Parragon Porsche who suggested the next step would be to take the engine out and check the tapits! I wanted a 2nd opinion so tried RPM who were very helpful and found a post cat lynder sensor fault. I booked it in at AMD and they found it to be a Precat lynder fault not Postcat! Has anyone else had a problem like this?

 

[DivineE]

When an engine management comes on and goes out again. It's usually the oxygen sensor (lambda sensor) in the exhaust thats to blame. If you are seeing faults from both though it makes me question whether its something else related like wiring to the sensors maybe?

I would trust RPM of the garages you mentioned. They are the ones I hear most good about. Perhaps worth mentioning that it has now come up as a fault for both the sensors at different times. May help them diagnose correctly rather than blindly replacing sensors and sending you on your way without checking other possibilities first.

 

[Stuggart441]

Thanks for this, come to think of it, AMD did replace the Oxygen sensor last year as the car pinked and this did sort the problem at the time. When they completed this years service, they over filled the engine oil and thats when the issues started.

 

[Richard_Hamilton]

Do you have the fault codes? Without them you are shooting in the dark.

Which RPM are you talking about, as there are at least two. If it is RPM in Cheddington, they are pretty good guys. Also I don't understand why you got RPM to check it out, but AMD to do the work. If RPM diagnosed the wrong lambda sensor and they had changed it, you would have had comeback on them to get it right. I would also be reluctant to take my car back to someone who over-filled it with oil, especially if it is to the point of damaging something.

Edit: Sorry -

Ed!!

 

[Stuggart441]

Hi there, thanks for your thoughts. I asked RPM at Cheddington to look at the car for a second opinion as AMD had suggested I have the engine removed so they could check the tapits? I dont know how true it is but ive been told if you take an engine out and start playing with it then write a blank cheque!..

RMP diagnosed the problem wasnt tapits but a post cat sensor fault but didnt carry the item in stock so ordered it and i drove over a week later to have it fitted. When I was back to get it fitted, RPM suggested that AMD had not properly reset fault after they had replaced the coils and in the week from the first visit to them, the fault hadnt come up again so I went on my merry way believing all was good. However a day later on came the light again, so, as AMD are nearer, I booked the car in there and told them what RMP had diagnosed so they ordered the part. I dropped it down to AMD this week and they ran a diagnostic and found it was the precat sensor and as they hadnt one of these in stock they would have to order one. Ive used AMD for years and have been loyal to them, the fast Audis and this 996 have been looked after well by them although if you feel them over filling the car with oil has caused these issues then maybe i should have some formal words?.. I guess I just want my car sorted once and for all as so far ive taken 7 half days holiday to drive back and forward from the workshops, parted with £1500 and its still not sorted..

 

[Richard_Hamilton]

I think the fact you say "they over filled the engine oil and thats when the issues started" made me wonder. It may be coincidence, of course. What was it that made you realise it was over-filled, and by how much? Was it smoking badly? Perhaps oil had contaminated one of the lambda sensors.

 

[DivineE]

ORIGINAL: Richard Hamilton

Perhaps oil had contaminated one of the lambda sensors.

This is what I was thinking reading the posts. I have not had a great experience with AMD and wouldn't personally use them again but that's only my expereince.

 

[996ttalot]

Normally, if you get the CEL on and it flashing and then goes off, it is a misfire. Typically you don't always get any pcodes either with this issue.

So as you said they replaced the coilpacks, and I would presume that they would have replaced the plugs at the same time, since that is typical cause of misfire.

When you had this issue, was the car hestitating as in misfiring? The only reason I ask, is that I have had this before, and in fact the cause was lack of fuel. It may be a non issue for you re fuel, but for me, since i have 60lb injectors on the car, the fuel gauge is inaccurate when it goes below the 1/2 tank marker, since from then on it is calculated based on the computer.

Just a thought.