Hello, guys, i'm new here. So couple days ago my 968 engine started to rattle. Everything started after I jumped the car with cables. When the revs go past 1.5k RPM there's a rattle noise coming from top of the engine. I read some threads and some people said to disconnect the variocam solenoid valve, if the noise goes out, there's your problem.
So I took off the solenoid valve plug off and now the sound is gone. Took off the cylinder head cover, took out that valve, gave it 12v and it seemed to work perfect. Cleaned it with petrol, put everything back together, plugged in and the noise is still there. Any ideas?

 

How old is the chain and pads? Oil pressure at hot idle? Are all the teeth on both gears? Battery voltage running?

 

it may be a coincidence that it started after jumping the car but I wonder if some damage was done to the DME? Try to find out how to check solenoid with engine running.

 

If you haven't already you should replace your chain tensioner pads. When they go, so does the entire top end.

 

Had the car for about 10 years now, it's got 100k miles. Havent changed the chain and the pads, but top pad had like 1mm groove. Chain on the bottom feels a bit loose and has an edge that you can feel with your nail.
Oil pressure at hot idle is about 2.5-3bars. At cold about 4.5bar.
All teeth on both gears seem to be fine.
Didnt look at the voltage, but the starter works great.

 

Plugged in makeshift light bulb and 1.5k RPM and up the light turn on. The light stays on without no interruptions, once i let go off the throttle, the light goes out. So DME works fine I guess..

 

 

Can it be, that somehow the chain slipped and now, when variocam turnss on and turns intake valve a bit, the angle is too great and it causes valves to touch the piston? Because, when variocam solenoid is not plugged in, there are no noises, engine revs perfectly... Oil viscosity, due to age, could do things like that or no? I drive like 1000-2000 miles each year.

 

Another thing, don't know when the fault code was stored, but with the accel. pedal procedure, it showed me 34th fault code, which is Hall Sensor

 

The hall sensor plug gets kinda crispy back there.

can you run a mechanical oil pressure gauge to see if there are any fluctuations in the oil pressure. Lindsey sells a little adapter with provisions for both.

 

So the hall sensor does not play role with my stuff, ye?
I dont have the adapter, I could try to find where to buy.. Looking at the oil pressure gauge it does not move

 

I may be incorrect but the hall sensor is on the ignition timing side of the equation.

this is the oil pressure adapter I was speaking about. https://www.lindseyracing.com/LR/Parts/928OILADAPT.html

 

Any other ideas?

 

We had a 968CS here at work ( customers car ) about a year ago with exactly the same symptoms , meaning only noisy with the vario cam solenoid connected electrically , once the 2 pin plug was disconnected the noise went away , everything was perfect , new timing chain and pads , made no difference to the noise , after a lot of research we ended up having to purchase from Porsche an exchange Vario Cam assembly & that fixed the issue .

From our research this symptom is not super rare in old age , it has happened to other owners in many countries , we concluded its something inside the vario cam assembly , may be a broken spring or something ??? , have no idea because you can not dismantle this item without damaging it and its exchange only from Porsche and we were not keen attempting to dismantle the old one in fear of not getting our core deposit back

 

Thanks for reply. So I think, buying second hand variocam assembly, would be the best option.. I'm new to porsche's, do you know where I could buy it? I'm from Lithuania, so shipping is needed.