DannyHoffman

My very recently acquired 2006 Turbo S 77,000 miles started misfire yesterday shortly after filling the tank with petrol.
The more I drove the worse it got until the point where it cut out completely and the engine check light came on.
I restarted and limped home

I have a Maxidiag EU 702 fault reader which supports a number of car manufacturers but not Porsche.
However the generic OBDII mode and the VW specifice mode read the following errors:

P0492 Secondary Air Injection System Insufficient Flow Bank 2
P2177 System Too Lean Off Idle Bank 1
P2179 System Too Lean Off Idle Bank 2
P0300 Random Mulitiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0305 Cylinder 5 Misfire Detected

It felt like coil packs and was due a new set of plugs so I changed them all today.

Whilst doing so I noticed that the hose to the secondary air pump on bank 2 was completely disconnected, possibly explaining the first 3 errors

I couldn't see any cracks on the coil packs and their part number ended in 07 which from what I have researched means they were manufactured in 2009 ish, around the time of the last plug change

The plugs were all similar colour.

I cleared the errors and the check engine light now stays off.

The car runs ok now, not sure if I am imagining a slight hesitation at low revs/light throttle or am I just a bit paranoid. Need to drive it a bit more to be certain.

Is there anything that could cause a misfire on all 4 of the front cylinders only?

Anything else obvious I should check?

Dilberto

You done good so far. Drive easy and see what codes return. Fix that SAI hose, though...

Porsche_Turbo

Check all vacuum lines, including the the T connector back of the intake manifold.

DannyHoffman

Drove it again today and it definitely still isn't 100% right. I got an occasional minor stutter both cold and hot. I haven't had a chance to plug the fault code reader in yet. Will report back later when I do

DannyHoffman

Fault reader had the following:

P2177 System Too Lean Off Idle Bank 1
P2179 System Too Lean Off Idle Bank 2

I cleared them and it still misfired, but I only drove a short way and the codes didn't return

I haven't checked for vacuum leaks yet

DannyHoffman

A bit more info to add. I looked back through the limited service history I have for the car and in April this year the car was taken for a diagnostic test. The hand written report has the following:

1) Secondary Air System Bank 2 Below Limit Value
2) Vehicle Electrical System Voltage Via Main Relay. No Signal

It doesn't give the P numbers.

I'm assuming the first error was due to the secondary air pump hose being disconnected, could this have been off since the last plug change in 2010?

The second error is a little less clear from a quick look on the forums. One post suggests it is to do with parking assist, another to do with a faulty relay for the fuel pumps and another for a low battery voltage.

DannyHoffman

Another couple of points.

After reading the forums yesterday I found a few suggestions that low battery voltage could cause strange misfire issues so I attached a trickle charger last night. This morning this is showing the battery voltage is still low. My car has done very few miles in the last year and since I've had it I've been doing various bits and pieces which would drain the battery (tailgate shocks, tracing a Bose amp fault) and only done short journeys.

I also read about the PCV/Oil air separation membrane and have checked mine. It has a 1/4 inch split and a smaller pin hole. I have temporarily put a dab of glue and some tape on these.

I will use the car today, even with the low battery, to see if things have improved.

ekstroemtj

buy a new one . They are not that expensive:

https://vanos-bmw.com/membrane-94810...enne-45l-450ps

DannyHoffman

"buy a new one . They are not that expensive:

https://vanos-bmw.com/membrane-94810...enne-45l-450ps "

Thanks, have done. Not sure how long it will take to get to the Uk

ekstroemtj

I was waiting about 10 days to germany

DannyHoffman

I drove it today, about 10 miles in total almost all in traffic.

The engine now has a lovely creamy feel to it 99% of the time, smoother than any of the other Cayennes I test drove whilst looking.

There were no fault codes logged but I'm am still getting a very occasional stutter.

I hooked the trickle charger back up and the battery voltage is still low.

I will see if it's fully charged by the morning

deilenberger

What does the voltmeter on the dash read whilst it's running? Or did they put the boost gauge in place of the voltmeter (to me - the voltmeter would be more important..)

DannyHoffman

"What does the voltmeter on the dash read whilst it's running? Or did they put the boost gauge in place of the voltmeter "

I have a boost gauge, no voltmeter.

The lights on my trickle charger indicate the battery is less than 80% charged. Once it is 100% charged I will test the battery, I have a digital voltmeter and have a test routine the confirms it doesn't have any weak cells.

DannyHoffman

Well the trickle charger reported the battery was 100% charged this morning and when I drove it staggeringly it was perfect!

Will test the battery later and report back

J'sWorld

If you do not drive often I would suggest a bettery tender. These are very power hungry voltage dependent vehicles.