2005 997 C2 engine trouble

[cartel]

Hi

The alternator brushes disintegrated at 105k miles, so I bought another whole alternator unit from eBay, fitted no problem checked the voltage at the battery it was above 14v. The battery was then flat the following morning so I bought another battery Bosch S4 figured the alternator cooked a cell before throwing the towel in.

Since these changes the check engine light is coming on and the car idles roughly when I comes off the choke or returning to idle from revving, in fact it drops lower than normal idle speed before reluctantly returning to 750, also getting rotten egg smells from exhaust gases.

Plugged in a code reader it's giving P0300, P0301,P0302,P0303 and occasionally P1090.

The car is very thirsty now , 18mpg . It seems to be running ok at medium to high revs though?

I've replaced no1 coil pack, no change still getting missfire fault code on that cylinder. I've cleaned the maf with electrical contact spray, to no real avail, although possible slight improvement.

I've ordered another new maf, clutching at straws now any ideas? I work on the rigs so the car gets left for fortnight unused, every time I come home and go to use it something else has broken on it!

[Dus10R]

Best case scenario, plug or plugs are fouled, you said you changed coil pack, did you check the plug?

If the plug is good and the coil pack is too, then it could be fuel pump, or even an injector. You know its not burning the fuel because your MPG has gone to crap, which could mean a stuck open injector thats flooding the cylinder and fouling the plug.

Just for grins, check your ground strap too, its a known problem on these cars and Porsche sells an improved part to fix it.

Worse case scenario is the DME is fried somehow but if your getting codes and none are DME related then thats probably not the case.

(just running thru in my head and typing as it comes to me...haha)

Rough idle, can be vacuum leaks too, look around in your engine compartment for any broke vacuum lines.

[Dus10R]

Another thought... Have you removed and cleaned the throttle body? They can gunk up sometimes and will cause the car to run poorly and die at idle. Also try a throttle body reset.

Turn the ignition key on but dont start the car, let it sit for about a minute, if you stand at the back of the car you should hear a high pitched whine and a few clicks as the throttle body resets itself. When its done and no longer making any noises, dont turn the key off but do start it and let it idle for 10 minutes or so...

Changing the battery could have somehow got the throttle body out of whack.

[cartel]

Hi

I'll try the reset on the throttle body, thanks for that... hopefully the new MAF will come tomorrow also.

I disconnected the ground lead from the battery this afternoon and left it for ten minutes. When i drove the car again soon after it was fine for 10 miles then brought up the same codes again, random miss fire, cylinder 1,2 and 3 miss fire detected. , also filled up 97 grade fuel.

It has been very wet here and now its freezing wondering if its weather related.

Stupidly i didn't remove the plug, I had enough trouble with the coil! The plugs were new 7K miles ago. I thought it unlikely that all the plugs or coils on one bank would fail at once?

[cartel]

Reseting the throttle body hasn't worked, unfortunately.... didn't attempt cleaning it as its absolutely freezing outside .

Still waiting for the new MAF to get delivered.

I'm just hoping its nothing to do with vario cams, although misfires all on one bank is it bit suspicious. Anyone have any experience of failures on that mechanism?

[RFM]

Given the misfires on cylinders 1 - 2 and 3, could be that you've hit the wires or sensors when replacing the alternator, which is indeed on the same cylinder bank. You never know.

[cartel]

Yep, I've considered that. Fitted a new MAF today it's made absolutely no difference, gutted.

Sprayed brake cleaner around that bank inside compartment, engine speed increased slightly I think there's an air leak. Gonna have to take it in $$$$$.

[cartel]

Hi

Just for the avoidance of doubt, cylinders 1,2 and 3 are on the left hand side of the vehicle, when viewed from the back?

I've just looked at the coils on the other side and they don't look good, plastic casing hanging off on one of them, which is making me wonder if I'm on the right bank!

[Loren]

Yes, 1-2-3 would be on the left side of the car as you sit in the drivers seat.

[cartel]

Thanks for that, hoped it might be the other way round... Calling Porsche Colchester in the morning, to book in diagnosis.

[cartel]

Just to let everyone know, the cars been at the dealership for two days, and the fault is the 'lift solenoid' on bank 1. I've agreed for them to replace it at a cost of four hundred pounds, just glad it's not more serious and i'll get the car back before Xmas, happy days!

Edited December 11, 2012 by cartel

[A-Aron]

On 12/6/2012 at 5:52 AM, cartel said:

Hi

The alternator brushes disintegrated at 105k miles, so I bought another whole alternator unit from eBay, fitted no problem checked the voltage at the battery it was above 14v. The battery was then flat the following morning so I bought another battery Bosch S4 figured the alternator cooked a cell before throwing the towel in.

Since these changes the check engine light is coming on and the car idles roughly when I comes off the choke or returning to idle from revving, in fact it drops lower than normal idle speed before reluctantly returning to 750, also getting rotten egg smells from exhaust gases.

Plugged in a code reader it's giving P0300, P0301,P0302,P0303 and occasionally P1090.

The car is very thirsty now , 18mpg . It seems to be running ok at medium to high revs though?

I've replaced no1 coil pack, no change still getting missfire fault code on that cylinder. I've cleaned the maf with electrical contact spray, to no real avail, although possible slight improvement.

I've ordered another new maf, clutching at straws now any ideas? I work on the rigs so the car gets left for fortnight unused, every time I come home and go to use it something else has broken on it!

I had the same problem only mine was tripping all the cylinder misfire codes (P0300 - P0306) and it ended up being a vacuum hose leak. There was a very small hairline crack in a rubber vacuum line were a metal hose is inserted into it. I tightly wrapped it several times with Gorilla Tape and it hasn't tripped the codes since. If it happens again I'll go ahead and replace the hose but I thought I would give it a go with the tape and it worked.