It won't idle

[Marc's 911]

Hi, I have recently purchased a 2005 Carrera 4S (40,000 kms/25,000 miles). After replacing a blocked LH catalytic converter the engine started fine (ECL disappeared) but after 15-20 minutes (whilst stationery) stalled and since will not idle. The only way to prevent it from stalling is to keep the accelerator depressed. Whilst in gear it drives fine but the instance the clutch is depressed and the revs drop below idle speed all warning lights come on and it stalls. At 1 stage it corrected itself but a few minutes later it happened again. What could be the cause?

PS. From day 1 I noticed that the engine cranked slower than on other cars and now even with booster cables attached it has difficulties starting. After reading a lot of posts on this excellent forum I'm aware of the starter/alternator cable problem which I will attend to first thing today. Having said that, I don't think that the 2 problems are related, or could they?

any advice highly appreciated

Marc

[RFM]

I would start with thoroughly cleaning the throttle body, and see what it gives as result. How to can be found in the discussions 986/7 and 996/7.

[Marc's 911]

I would start with thoroughly cleaning the throttle body, and see what it gives as result. How to can be found in the discussions 986/7 and 996/7.

Thanks for your advice. I'll do that asap.

[PAULSPEED]

Also wipe the MAF sensor good and clean.

Paul

[Loren]

DO NOT wipe the MAF sensor - use only MAF sensor cleaner spray and allow it to dry before starting the car.

[Marc's 911]

Thank you all for the advice. As mentioned earlier besides the idle issue the engine would not crank properly and after checking cable and the state of the battery (both OK) it was decided to remove the starter motor. Out of the car it worked fine but fitted to the car would crank the engine only the first couple of tries and only when cold. Cause; loose shaft. Under load especially when hot form spining and when engine running from the engine itself the shaft would try to move of centre which in turn would make the turning much harder. Identical symptoms to a weak/dieing battery!!! I did the removal and fitting myself (at my mates workshop) so total cost for the reco was $30 (good East European prices where I'm on holidays at the moment).

1 problem fixed but the idle issue has changed into something more problematic, namely (Im translating from another language so the wording might not be exact);

Error Code 0016 - crank shaft position sensor (row 1, sensor A) Assigned Error?? (or something like that),

Error Code P0300 - multiple cylinder missfire

Error Code P0301 Cylinder 1 missfire

Error Code P0302 Cylinder 2 missfire

Error Code P0303 Cylinder 3 missfire.

PS. Last week after replacing (with a second hand unit) a faulty/blocked LHS catalytic converter I also changed all the spark plugs. My mechanic's (and my) diagnosis is suggesting faulty ignition coils but why so many at once? Before I order new 1's can anyone give some advice please?

[PAULSPEED]

First thing I thought of when I saw your codes. Look

for cracks on the old coils.

Paul

[Marc's 911]

First thing I thought of when I saw your codes. Look

for cracks on the old coils.

Paul

Hello, swapped location of coils 1,2,3 with 4,5,6 and vice versa but the missfire still remains at cylinders 1,2,3 so the coils are OK. The Error Code 0016 - crank shaft position sensor (row 1, sensor A) Assigned Error?? (or something like that) is also still there. This (I think) means that that the crank shaft correlation to the camshaft is wrong. My mechanic said that a chain could be worn (it equals to it being fractionally longer) and/or it could have jumped by a notch. If that's the case it would not allow the engine to idle freely. Anyone with any suggestions?

[PAULSPEED]

You may want to give these guys a call. They

use to sell a cam shaft guide that was alot stronger

then the stock guide.

http://www.lnengineering.com/hardware.html

I cannot find it but I have seen it before.

If your chain jumped a tooth, then it would be safe

to say that a valve would ran into your cylinder. I would

look into installing a new valve chain guide.

Paul

[PAULSPEED]

This is getting closer.

http://www.lnengineering.com/ims.html

Paul

[PAULSPEED]

Here is some talk on cam chains.

http://www.lnengineering.com/buyingausedporsche101.pdf

Paul

[Marc's 911]

Here is some talk on cam chains.

http://www.lnengineering.com/buyingausedporsche101.pdf

Paul

Hello, is it possible that a pending/in-the-making IMS failure is causing this wrong crank shaft to camshaft correlation?

Marc

[Marc's 911]

DO NOT wipe the MAF sensor - use only MAF sensor cleaner spray and allow it to dry before starting the car.

Hello Loren, do you have any ideas/suggestions as to the problems I have described most recently?

Marc

[Loren]

Usually a bad crank position sensor will not even allow you start the car. I saw one that was intermittent once and it would run fine until the car reached operating temperature - then it open and you could not restart the car.

What are you reading the codes with? If not Durametric or a Porsche tool (PST2 or PIWIS) then I suggest using one of those. To have misfires on one only bank usually points to a cam sensor issue.

[Marc's 911]

Usually a bad crank position sensor will not even allow you start the car. I saw one that was intermittent once and it would run fine until the car reached operating temperature - then it open and you could not restart the car.

What are you reading the codes with? If not Durametric or a Porsche tool (PST2 or PIWIS) then I suggest using one of those. To have misfires on one only bank usually points to a cam sensor issue.

Hello, our Porsche tool (PIWIS) could not read the DME (it reads everything else though) so we waiting for a newer version to arrive. In the mean time we're using a different brand (will let you know the name shortly). Could the sensor itself be faulty? If so which 1 - the camshaft 1 or the crankshaft 1? - the error code says crankshaft posision. We pulled out the crankshaft sensor (location at the gearbox side??) and it was covered with lots of metal filings. Put it back in after cleaning. Is it possible that the chain jumped a notch (note, the catalytic converter that blocked up was on the same bank)? Is it possible to check/remove/refit - if necessary, the left bank's timing chain without engine removal?

Marc

[Loren]

Is this a PIWIS clone from China? If so, please read the codes again using a real PIWIS.

In my previous post I was trying to show that those codes don't make sense.

If you have significant metal floating around in the engine - it likely needs to be rebuilt (sorry).

I would pull the oil filter and have a look at it also.

[Marc's 911]

Is this a PIWIS clone from China? If so, please read the codes again using a real PIWIS.

In my previous post I was trying to show that those codes don't make sense.

If you have significant metal floating around in the engine - it likely needs to be rebuilt (sorry).

I would pull the oil filter and have a look at it also.

No it's a real 1. It had played up and we're waiting for a replacement. The metal filings were stuck to the pulse sender (crank shaft sensor?) mounted at the gearbox side but not inside the engine.

1) Are the hall senders the same as camshaft position sensors (Im about to swap them around)?

2) Can the timing belts L + R be inspected / corrected (if actually jumped a notch)/ replaced without removing the engine?

Marc

[Loren]

I would start with the crankshaft sensor - if it is marked or damaged then it needs replacement. Then reset the codes and re-test.

[PAULSPEED]

I found the cam chain tensioner.

http://www.flat6innovations.com/shop/home.php?cat=316

Paul

[Marc's 911]

I found the cam chain tensioner.

http://www.flat6innovations.com/shop/home.php?cat=316

Thanks.

1) is it possible for a timing chain to jump a notch on 911?

2) is it possible to inspect/correct a timing chain without pulling out the engine?

Marc

Paul

[Marc's 911]

I would start with the crankshaft sensor - if it is marked or damaged then it needs replacement. Then reset the codes and re-test.

Hi Loren,

after swaping all the sensors around I finally narrowed it down to left bank actuator (camshaft) which when moved to right bank replaced the previously misfiring on cylinders 1, 2 & 3 + code P0016 with misfiring on cyl. 4, 5 & 6 + P0018. To be 100% sure I then have moved it back to it's original position on the left bank and the misfiring on cyl 4, 5 & 6 got replaced with misfiring on 1,2 & 3 (as it was originally prior to movement). When replaced with a brand new unit the all error codes (incl 0016 - correlation between cam & crankshaft) disappeared and haven't come back since. However 2 problems still remain, starter motor hardly winds the engine (but it only happens when the engine is at operating temperature) and it won't hold idle when say slowly changing gears or pressing the clutch to bring the car to a stop (9 times of of 10 it'll stall). Strangely enough if you start the car (especially when cold) it'll idle perfectly for hours until you rev the engine and let go the accelerator then it most of the time but not always stalls. I have since cleaned (wiped) the throttle body and sprayed the MAF sensor (which seemed to be very clean) with a proper spray.

Does the throttle body need to be re-calibrated as is the case with some other cars?

Another thing, once whilst idling (perfectly) for 2-3 hours I was watching the temperature read out (on the diagnostic tool) which over that long period of time was gradually raising and when it reached 102-103 'C the warning light located on the temperature gauge itself came on and the on-board computer displayed a message saying that the rear compartment fan isn't working or is disconnected (I had disconnected it and was aware of it) all this while my temperature gauge never showed more than 80'C.

Could the temp. gauge need to be adjusted/re-calibrated or is it a faulty the coolant temp. sensor?

Could you tell me which sensor (and it's location) controls the rear compartment fan as it runs for a very long period of time (after switching the ignition on) even when the engine isn't warmed up or hasn't even been started?

Marc

[Loren]

My advice is solve one problem at a time - and confirm the fix by resetting any fault codes.

The idle and acceleration programs re-learn after a DME reset (usually a battery disconnect) - that is normal.

The rear compartment fan and engine compartment air temperature is a separate reading from coolant temperature. The usual cause of errant readings of engine air temperature is that the sensor has fallen out of it's holder and is laying on the hot engine parts.

On 997-1 there was also a TSB fix (DME program as I recall) for bad readings - you should make sure this fix has been applied to your car. Any dealer should be able to check that based on your VIN.

[Marc's 911]

Thanks for quick reply. After replacing the actuator to date there have been no fault codes at all but not sure whether my DME has had the TSB fix applied (I will ask at the nearest dealership). When plugs for the throttle body and MAF are disconnected then I get 2122 & 2127 error codes.

Could you tell me whether any of them relate to MAF plug being disconnected?

Could you also tell me where the engine compartment air temperature sensor is located?

[Loren]

P2122 Throttle valve adjusting unit – potentiometer

P2127 Throttle valve adjusting unit – potentiometer

You would get this codes if you unplugged the throttle position sensor.

[Marc's 911]

P2122 Throttle valve adjusting unit – potentiometer

P2127 Throttle valve adjusting unit – potentiometer

You would get this codes if you unplugged the throttle position sensor.

How can I check/diagnose whether the throttle is working properly since the engine stalls as described earlier?