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youtube has some great videos how to do this including removing the front seats.
Love the screen name!
I ended up just getting it to pass the E Test and that was good enough for me. I had both fuel pumps and a fuel pressure sensor replaced. Crazy the PSI these things operate at! I also recently noticed a small leak near where I had the flex pipe repaired - I think that's also throwing off some errors. Ill plug it into my Durametric in the next couple days to see if that eliminated the 12A2 and let you know. Once it passed the ETest I never looked back since it has run well for ages. It's so old now Im only keeping it running at this point.
I'm at a loss what to even try next ... ANY suggestions appreciated !! Compression 240-245 in all cylinders except for #2 which is 200. I think these are good numbers for a 10 year old engine. When the lifters were replaced so were a pile of gaskets, seals and hoses. Very very minor scratches in multiple cylinders. This doesn't look related to scoring, so common in these questionably designed 4.8l engines. Rough idle, knocking and heavy smoking at low RPM acceleration – often car struggles after coasting in gear 5 or 6 then having to accelerate. Shreds oil and spark plugs even when stuffed with Lucas high mileage additive. Toronto's best independent Porsche shop did all but the AOS: The lifters were replaced Camshaft and tensioners out Carbon cleaning of valves and intake system New actuator solenoid for the 2nd stage valve lifters New vacuum pump New ignition coils New top engine mount All AOS parts and hoses New spark plugs every 50 KM After all that work cylinder 2 or 3 fouled right away so the shop said it was scoring and doomed. They filled it with Lucas and replaced plug 2 suggesting I should trade it in ASAP. Once I realized how absolutely worthless these cars are after 10 years I figured I'd just hang, onto it until I could see if it was fixable. If you drive it hard in manual the car seems perfect with tons of power - that's my main reason to try and fix it. If only I could drive the local 40km/hr streets in 1st and 2nd gear at 2500-3000 RPM without drawing angry stares from the noise and occasional light roll of coal.
Did you ever figure this one out? I also have a 2008 Cayenne V6 running OK but codes for P12A2. It's not running perfectly - every once in a while at idle the RPM drops about 150-200 and its very slightly rough for about a second. This may be when the CEL gets triggered. It only takes a couple minutes of city driving to post it as pending then pops up as a CEL after about 20km - always at idle. I have to pass Ontario's check engine light test. The car has been trouble free for 9 years (other than being on its 3rd drive shaft) knock on wood ;) Funny how my 2008 V8 burns more oil than a two stroke motor and it passed the Ontario ETest with flying colours. From Loren's list, I've already replaced: -- High pressure sensor -- Pressure relief valve -- High pressure pump This week I'm going to take a stab at the low pressure pump and filter possibly also the tank vent. A friend with the identical car had the same problem resolved a couple weeks ago by replacing the tank vent. He also had every single part of the fuel system replaced under warranty until Porsche figured out that there was a part sticker stuck in his intake so all his pumps, valves and sensors are newer than mine. After that, from Loren’s list, I’m left with the injection valve. I’ve also read that some people have resolved the P12A2 by fixing: ????? -- vacuum leaks -- PCV valve -- fuel pump cam follower? -- rear main seal I don’t mind spending money on the fuel system since I hope to keep it a couple more years and 160,000 KM is about the time for a Cayenne’s fuel system to crater. The car has been amazing for years. Anyone else have experience with this P12A2? I’m sure it must be common if my friend with the same car had it at almost the exact same time. Once after replacing high pressure pump I also had a lean code (not sure which one) also makes me think leak? Here is the output from my cheap ODB reader: FuelSys 1 CL CL CL FuelSys 2 CL CL CL Calc Load 14.1 14.1 23.1 ECT© 90 90 85 STFT B1(%) 0.8 3.9 15.6 LTFT B1(%) -5.5 -2.3 1.6 STFT B2(%) -0.8 2.3 17.2 LTFT B2(%) -3.1 0 3.1 RPM 697 682 779 Speed 0 0 0 Spark Adv deg 13.5 13.5 -4.5 IAT C 9 12 12 MAF g/s 3.13 3.05 3.55 TPS% 11.4 11.4 11.8 Run Time sec 1009 465 253 Fuel Pres kPa 3400 3510 3390 Command EVAP 0.00% 0.00% 0.00% BARO kPa 98 98 98 ECU Volts 14.276 13.923 13.994 Load Value 12.2 12.2 20.0 EQ Ratio 0.999 0.999 0.999 Rel TPS% 0.8 0.8 1.2 Ambient C -2 -3 -4 TPS B% 11 11 11.4 ACC Pedal D% 14.5 14.5 14.5 ACC Pedal E% 7.5 7.5 7.5 Command TAC% 1.2 1.2 2.0
Did you get it fixed? Who did you take it to for the repair? I've been living with the same problem for months now. My local independent told me they don't have the tool required to line up the camshaft after the repair so they can't do it. Does anyone know of a good independent Porche mechanic in the Toronto, Mississauga, Oakville or Burlington area that could do this kind of repair?
Any update? I've started down the same path of repairs. I've had the rough idle problem for about a month and it seemed just an annoyance until last week when after a long highway drive I had to drive for an hour in stop and go traffic. The car started to feel like it was going to explode! So bad I had it taken by flatbed to my local shop. They replaced the plugs and coil packs and tried to clean the solenoid valve but the smooth idle only lasted about a kilometer. I'm going to have the solenoid valve replaced this week.
I have exact same problem on an 08 S. Anything above 800 RPM and its so smooth. Below 800 RPM rough idle. I dont have all the codes observed but think it's the "valve lifter solenoid bank 1" + misfires. I'm dreading taking it to the dealer but I'm not sure my Non dealer mechanic will be able to do better. Hoping you found the cause of this before I pay the dealer a fortune to try and figure out what must be a common issue.