CEL after new plugs and coils.

[kevin ryan]

I just picked up a well taken care of high mileage tt, so I had new plugs coils, both diffs serviced, oil service, brake flush so I now have a baseline. about 50 miles after service, cel pops up.

shows misfires on 3 and 6 cylinders. car runs excellent however. ive been using my indie for 20 years and he is a turbo specialist(built a 935 for a shop car).

hes stumped because the car runs so well. it does have a 1 bar flash, tubi exaust, awe headers. I don't know what company did the flash though. im wondering if the MAF sensor may be fouled, or the flash on ECU is to blame.

This is my 1st 996 tt, very different from my 930s.

Am I missing something obvious? should I send my ecu to a reputable Porsche tuner?

any and all advice is very welcome. The car is a blast to drive...pss9s front and rear aftermarket adjustable anti sway bars and drop links, handles very well.

But the CEL is driving my crazy.

 

[Loren]

30 minutes ago, kevin ryan said:

I just picked up a well taken care of high mileage tt, so I had new plugs coils, both diffs serviced, oil service, brake flush so I now have a baseline. about 50 miles after service, cel pops up.

shows misfires on 3 and 6 cylinders. car runs excellent however. ive been using my indie for 20 years and he is a turbo specialist(built a 935 for a shop car).

hes stumped because the car runs so well. it does have a 1 bar flash, tubi exaust, awe headers. I don't know what company did the flash though. im wondering if the MAF sensor may be fouled, or the flash on ECU is to blame.

This is my 1st 996 tt, very different from my 930s.

Am I missing something obvious? should I send my ecu to a reputable Porsche tuner?

any and all advice is very welcome. The car is a blast to drive...pss9s front and rear aftermarket adjustable anti sway bars and drop links, handles very well.

But the CEL is driving my crazy.

9

 

You need to run a fault code scanner. It will tell you exactly which cylinder(s) the problem it on.

[kevin ryan]

thanks Loren. do I need a Porsche specific fault code scanner, or is it a generic tool? where to buy?

thanks for responding

kevin

[Loren]

Just about any scan tool will give you this necessary information on cylinder misfires.

[wross996TT]

After you get the appropriate codes, there is a grocery list of things to check.  Typically, coils and plugs are the culprits, but since you just had them changed...make sure they were installed correctly and gapped correctly....swap out the ones that are misfiring with ones that aren't?...Did you do a pressure check?  Wastegate, N75 Valve....

[kevin ryan]

Out looking for fault code scanner now

Thanks for the common ones. Im slightly irritated at my indie that he hasnt been more forthcoming with codes that show up on his handheld.  Like hes actually spending time diagnosing problems,  when the codes are right there. I hate to say harbor freight,  but their Zurich gets high ratings for a buck and a half.

 

 

[wross996TT]

Realize that unless it is a Porsche specific tool (PST2, PIWIS, Durametric), some codes may be difficult to ascertain or reset.  Hopefully your indy has a PST2 or PIWIS if they work on Porsche.

Edited April 18, 2019 by wross996TT