marucus1

I ordered up VarioCam sensors for both banks and replaced them last night

where is the VarioCam sensors located and is it easy to DIY?

Petza914

There are at least three different components being discussed here, kind of interchangeably, which they shouldn't be.

1. Crankshaft Position Sensor. The car has one of these as since it has one crankshaft
2. Cam Position Sensors - there is one of these for each bank. It's a Hall sensor and is often the culprit when only one bank is misfiring
3. Variocam Plus Sensors and/or solenoids. These control the shift in the valvetrain (heads) that enable the higher lift and longer duration of the valves remaining open at higher RPMs. These usually throw a specific code that references the Variocam solenoid.

jstdenis

Have the same problem(2005 Carrera, non S). Been going on now for three years. Auto is in storage six months; CEL with multiple cylinder misfires upon startup out of storage. No signs of misfires, only experience a beep which focuses my attention on the instrument panel and CEL is lit up and codes show multiple misfires; no signs that engine is running on less than six cylinders. Runs like a top for two or three months and out of the blue on cold start ONLY another beep and CEL is illuminated; misfires on all cylinders. Absolutely NO signs that the engine is misfiring; clear codes. Runs like a top for another two or three months and CEL repeat on cold start and not so much as a hiccup in performance however codes show misfires on all cylinders. My indy has not found anything; however I have not authorized exhaustive( and expensive) trouble shooting this issue. A Porsche misfiring on all cylinders should shutter or worse!!(no untoward experience other than a 'beep') I simply clear the codes and move on. Until I experience something more than a 'beep' its a twice or three times a year nuisance.

rick500

I'm curious how shops check out coils?? When I was a commercial electrician, we used a 'megger' to capture the insulation resistance change in wound devices, e.g., motor windings, coils etc. a DECREASE (over time) in resistance was a sign that the winding insulation was breaking down.... However, never heard of an auto mechanic using a megger??

Petza914

Usually the coil falures on these cars are due to the insulation on the back of the coil pack becoming compromised (cracked). Easiest way to test it is to mist the back of the coil pack with water while the engine is running or if misfiring gets worse when driving in the rain. Alternate methods are to move the coil from the misfiring cylinder to one that isn't misfiring and see if the misfire follows the moved coil.