997 C2 Misfire - P0660 Code Query

mark911rsr · 12 Aug 2019

Hello everyone - I'm a long time lurker on this Forum , and have gleaned a lot of useful information and knowledge from posters on here :worship:

I am a fairly recent convert to watercooled 911s , having owned aircooled cars , and 924/944s for years - Inow realise what I have been missing

Anyway , my issue is with my 2006 manual 997 C2 , in which I have covered about 8,000 mainly trouble -free miles in the last 18 months.

About a month ago , the EML came on and the car misfired badly at the end of our drive , which is a fairly rough stone track , two days in a row at exactly the same spot , where I stop to join the road.
Both times I turned it off , restarted and drove 10 miles or so with no issue , and 8 hours later returned home, again with no problem.

We then went on holiday for a couple of weeks , and this weekend , I started it up - all fine - got to the end of the lane - and same thing again
:x . Unfortunately this time , restarting had no effect .

I connected it up to my code reader and got cylinder misfire codes on cylinders 1, 2 and 3 , and also code P0660 - "Intake manifold tuning valve control circuit/open bank1"

I cleared the codes , restarted the car , and the EML was back on almost immediately , throwing out the same codes.

Can anyone shed some light on my next steps - I'm not even sure what an intake manifold tuning valve does ?

Any help would be gratefully received.

PS I replaced plugs and coil packs about 4000 miles ago

Thanks

Mark

deMort · 12 Aug 2019

Well .. i have an idea but it does not tally up with the inlet fault code .. well ... maybe but i've not seen that code with this fault before ..

Misfire on an entire bank is usually down to a variocam or high lift solenoid ..

Both are oil operated .. my guess is it's the high lift solenoid thats sticking .. the tappets get stuck in high lift ... air/fuel mixture can get pushed into the inlet manifold and then used on the other bank ..

The car gets confused as its altered the fueling on x1 bank but sees a response on the other bank.

Ok .. im waffleing .. i know .. sigh .

High lift solenoid ( there is NO fault code for this on a 997 ) .. you can either swop them bank to bank to try and see if the fault moves to the other side .. this will prove it .. or you can just replace it .

The solenoid is about £110 .. best to change the seal as well .. it's a guess .. but it's an educated one shall we say and i have seen a few of these over the years .. minus the inlet code though .

Your other choice is book it in at an indy .

Fault code for the inlet ..image below ..

I'm struggling to see how this would cause a misfire on x1 bank only but it IS a seperate fault from the solenoid if that is the cause of the misfire.

There is a grey electric valve that operates it , these are known to fail .. it basically alters airflow in the inlet manifold at different rpm .. it should be open at low rpm though .

Tuning flap is no.3 ..

Where there any other codes besides misfires on 1,2 and 3 and this code ?

mark911rsr · 13 Aug 2019

Many thanks for all that

, it all seems to make sense - I hadn't realised there was no code for the solenoid failure.

I'll try swapping that first , and if that cures the misfire , maybe the 0660 is an unrelated fault.

The only other code that came up was multiple misfire on 1,2 and 3 , which I guess is expected?

Once again - thank you so much for taking your time to explain this , I will update this thread with my progress .

deMort · 13 Aug 2019

The misfire code is all we normally get in relation to the high lift solenoid fault .. hence im leaning towards that but its only a guess as such .

the 0660 is .. i think a separate fault .. not one i've seen before but to me i'm struggling to see how this would cause the faults you have ... possible as is anything .. i just can't see it unless someone can explain it to me .

It's still a fault .. it still needs looking at and the info is above in the images .. it may even be disconnected .. but to me the fault is more likely the valve that operates it .

Either way there's a couple of things to look at .

Personally i would tend to replace the solenoid rather than swapping as it's not a huge amount of money and even if it's not that it proves a point and you have a new part .

parts that are about 1 hrs labor in cost then i tend to say at work replace ..

More than that then diagnose if possible.. but you can't with these i'm afraid other than swapping and much driving ... labour at work would be the same as replacing so not cost effective .

You will need new seals both sides if you swop though depending on how rusty they are .

mark911rsr · 14 Aug 2019

Thanks deMort ,

I took the solenoid out yesterday , and a new one has just turned up now - so I'll fit that later on and report back - fingers crossed .

It seems that the actuator for the inlet manifold flap is on the back of the engine , and will need a fair bit of dismantling to access ? Is this the case do you know - or is there an easier way to get at it ?

Thanks
Mark

deMort · 14 Aug 2019

It's not that easy to get at .. throttle housing needs to be removed and then probably the rear cross pipe as well .. the bit its bolted to ..

i would start by leaving that in situ and checking the pipes are connected between that and the grey electric valve .

As i've said my hunch would be this electric valve and it's not going to be easy to check .. if you had sports exhaust you could swop it with that solenoid and see .

I've just looked back at my posts .. other than talking about the solenoid i didn't say which one it was ..

just to be safe it's the one in the center of the cam cover .. the one at the far end is the variocam solenoid .

38 here is the correct one ..

https://www.deroure.com/diagrams.asp?MAK=3&MDL=26&TBL=2757&SMA=&SMO=0&ST=&SC=0

mark911rsr · 15 Aug 2019

Thanks again deMort.

Right ... Good News .... You were 100% correct , with the new solenoid fitted , the car now runs perfectly , with no misfires , and no EML ... nice easy fix.

Unfortunately , although my icarsoft POR2 worked perfectly a couple of days ago , reading and erasing codes , it has now decided to play up , and though it connects fine , if keeps rebooting itself at random different points in it's operation - so as yet I've been unable to see if the P0660 will reoccur .

However the car still drives fine , with plenty of power as it did previously.

Just a thought - I recently fitted a Valvetronic exhaust , which obviously involved me tapping into the vacuum circuit. The exhaust works fine , so I'm assuming there is no vacuum leak - but do you think this may cause issues with the electric valve ?

Thanks - Mark

deMort · 15 Aug 2019

This has actually just made my day !

Work life can be unpleasant at times .. well a lot of the time but to get a fix , to get something right with so very little info to go on ( you have no idea the amount values and stuff i look at normally on a tester to try and diagnose faults )

... it still gives me a buzz

Ok .. now i'm grinning like a cheshire cat ...

We need to see if the 660 fault is still active .. i'm thinking it will be ..

This vacuum take off for the exhaust .. it's possible this is related ( its a vacuum based system after all ) .. only way to check though is with an active reader to see if its still there then maybe unplugging the vacuum take off and see if that stops the code .

After that we are still back into pulling it apart to get at the bits and a visual check .

I would say you have some time now as the car runs ok .. i think this 0660 code is more of a subtle difference to the driving of the car than the misfire one ... it will fail open basically .

It would be interesting to know if this fault happened at a similar time to the exhaust being fitted :?:

Also .. any pictures of where you cut into the vacuum line ?

Welcome to send them here if you wish ..

[email protected]

EDIT ..

I'll just clarify the no fault codes for this high lift solenoid ..

There are codes but only for an open circuit , this is done with ign on , engine not running as the car checks every system to see if its connected .

The car though can not see if this solenoid is actually doing what it should with the car running .. hence i refer to it as no fault codes for this solenoid .

Second EDIT ..

It may seem like an easy fix but not so much for me .. i'm the one telling you to spend good hard earned money on an educated guess from me .. it does worry me .. trust me .. it does .

mark911rsr · 16 Aug 2019

Haha - educated guesses are often the best ones - and I have an idea your guesses are far better educated than mine :grin:

I haven't had chance to play with the code reader again , or take any photos - but I'll have a play around at the weekend , and send you some photos then.

Thanks again deMort - you're a star !

997 C2 Misfire - P0660 Code Query

mark911rsr

New member

deMort

Monaco

Attachments

mark911rsr

New member

deMort

Monaco

mark911rsr

New member

deMort

Monaco

mark911rsr

New member

deMort

Monaco

mark911rsr

New member

Similar threads

Latest posts

New Threads

Porsche Model Range

Porsche 911

Porsche Hypercars

Other Current Porsche Model

Porsche Legacy Models

Forum statistics