Variocam Solenoid breakdown?

Hi Guys, after startup once engine up to temperature if I idle at lights etc motor gets noticeably a little lumpy and enginecheck light comes on. If I drive off it will often go out again and run fine. Before i go the bore score route, on research I am being pointed in the direction of the vario cam solenoid breaking down. If I put OBC scanner on it says misfire cylinder 2. Any thoughts or similar experiences? As at the moment it is only occasionally it happens. Thanks, Al

my understanding is that a solenoid fault would give a whole bank misfire rather than a single cylinder. Also usually if you keep it at high revs the car runs fine, but at lower revs it doesn't. The solenoid faults are usually due to the connections breaking down and the circuit shorting out at the housing IIRC. Could it not be a faulty coil pack? I'm sure Demort will be along shortly to tell you what I've said is jibberish! 8)

Yes it's had plugs and coil packs, no doubt he will say bore score etc, it has had low temp stat for the last 2 years and just started this problem so was hoping for alternative diagnosis.

I would certainly be looking at the coilpack and then the plug. Both cheap items if bought individually, though a bit of a pig to replace. Swap the coil pack to another cylinder and see if the misfire follows it.

If it is a solenoid problem it is not a cheap fix. I recently had my bank 1 done and was told to be thankful that it wasn't bank 2 as the exhaust has to come out to do it. Hopefully you will not have that expense .

If code reader says misfire on a specific cylinder its probablt that. Swap plug and coil pack with its neighbour and wait for it to happen again. My bank 1 solenoid is currently duff and I'm awaiting a new solenoid. Manifold, back box and bracket have to come off to remove rocker cover and gain access.

Thanks, as I said in earlier post I have changed all plugs and coil packs already.

So did it do this before or after the new coil packs & plugs were fitted......or both? I'd still swap a couple round and see if it shifts the fault to a different cylinder. Didn't someone has an issue earlier this week and demort knew instantly it was the plug gap on (one of) some new plugs fitted.

Ah here it is. It was Frank(FZP): http://911uk.com/viewtopic.php?t=130180

As mentioned, move things around associated with that cylinder, if the plugs and coil have been changed the injector is another thing to look at, but I had a plug missfire a few years ago and the plug had only done around 5000 miles before it went faulty. Took some time to eliminate as I discounted the plugs as they were new.

Actually spot on :thumb: If vario cam and not plus then you would normally get a single bank of misfires and not just one .. But thats not to say its not that .. the slippers wear so timing is off .. it might technically just be at the border point were a slight problem on no. 2 is being made worse by a worn vario unit. Vario plus is a bit different as its a different design with a seperate high lift solinoid .. you would get a bank of misfires with this system and i think this is the system you have .. im not sure the change over year . Having said that i agree with everyone alse here .. i would be swopping components to another cyl or bank and retesting .. Soo plug / coil are the easiest , do them first then follow up with the injector .. New items can fail so they still need checking . If none of that moves the fault then move onto the more expensive items but this is an intermitant fault .. something like bore score and i would have thought it would be a permanent problem .. its also pretty rare .

I've got the same issue and it's diagnosed as the solenoid on bank 1, having it sorted at my indi in September.

Don't suppose you have a rough estimate for this as I might be suffering the same issue? :thumb:

6hrs labour and around £350 for the part.

You also need to factor in how many exhaust manifold bolts will snap as the manifold needs removing to do this job . One this week and all 6 snapped .. that made a big difference to the end cost .