997 hard to start when engine is warm

[lido901]

2007 997 c2, after driving even a short time or over 1 to 2 hours, after stoping for a short time like gas stop or 711 stop, the car is hard to start. it never fails to start but on some occasion it feels like the battery will run out juice.my battery is only 1 month old. the car has 70k .

[jwetering]

I had this problem, and solved it by installing a bigger battery.

The story I have heard but never verified is that there is an undersized/poorly made crimp on the main ground wire which limits the flow of current during startup.

This isn't as much of a problem when the engine is cold because the tolerances are looser. When the engine is hot though the tolerances tighten up and the flow of current is barely able to overcome the frictional forces.

Like I said - a bigger battery solved my problem and I needed a new battery anyway. In your case I do believe that fixing this crimp will solve your problem.

[JFP in PA]

Originally Posted by jwetering

I had this problem, and solved it by installing a bigger battery.

The story I have heard but never verified is that there is an undersized/poorly made crimp on the main ground wire which limits the flow of current during startup.

This isn't as much of a problem when the engine is cold because the tolerances are looser. When the engine is hot though the tolerances tighten up and the flow of current is barely able to overcome the frictional forces.

Like I said - a bigger battery solved my problem and I needed a new battery anyway. In your case I do believe that fixing this crimp will solve your problem.

Perhaps, but I would still check the primary leads for voltage drop when warm. Internal wire resistance rises with temperature, resulting in excessive voltage drop and you get hard starting.

[impactbumper]

Battery cable is your problem. Replace it and be done. Chronic issue. Dealerships will ask you a lot because they would want to drop the engine. Manual transmission, absolutely not necessary, tiptronic, could be a nightmare with engine on the car.

[gulfster]

I have this problem as well. When you say you installed a "bigger" battery, what exactly do you mean? What is safe to use?

Thank you.

[jwetering]

Originally Posted by impactbumper

Battery cable is your problem. Replace it and be done. Chronic issue. Dealerships will ask you a lot because they would want to drop the engine. Manual transmission, absolutely not necessary, tiptronic, could be a nightmare with engine on the car.

Which wire is that ? The negative lead that connects to the battery itself ?

[JFP in PA]

Either of the primary (large diameter) battery cables; often both.

[FPB111]

If the engine spins fast as normal but won't catch it might be the purge valve is sticking open. It lives near the alternator.

Canister Purge Valve Replacement - 996 Series (Carrera, Carrera 4, Carrera 4S, Targa) - RennTech.org Community

$33.64 with free shipping on Amazon (http://www.amazon.com/Bosch-0280142308-Purge-Valve/dp/B001COAS8M)


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[Traveller]

Originally Posted by lido901

2007 997 c2, after driving even a short time or over 1 to 2 hours, after stoping for a short time like gas stop or 711 stop, the car is hard to start. it never fails to start but on some occasion it feels like the battery will run out juice.my battery is only 1 month old. the car has 70k .

Easy fix with a few possibilities as this happened on my friend's 997.

The usual fix as "recommended on forums" and not the cheapest is the harness replacement that goes from the junction at the transmission to the starter and alternator. My friend already ordered the part without first inspecting it which makes you a "parts replacer" much like those found in shops. The part is not overly expensive but time consuming to install which is what I did, since he had the part.

That did not solve the issue...no surprise there.

While he was installing a new starter that he also happened to have, I was taking the old starter apart. I had him going as I said "it is not the starter", but I was joking as I showed him the armature in his old starter.



I rebuilt his original starter and installed a new brush plate. Works like new. Full details here...
https://www.smugmug.com/gallery/n-k4hmS4/

Same armature all cleaned up...

[rbogh901]

That looks great. I wonder if I will have to try to do mine at some point. I had a similar problem when I first bought my car a few years back.. I had a slow starter when warm but now it seems to have resolved. Likely will come back someday. What did you use to clean it with?

[Traveller]

Originally Posted by rbogh901

That looks great. I wonder if I will have to try to do mine at some point. I had a similar problem when I first bought my car a few years back.. I had a slow starter when warm but now it seems to have resolved. Likely will come back someday. What did you use to clean it with?

The whole starter cleaning process started with using a water-based degreaser, Facto AT30 from Swish in Canada and Swish USA. A product I have been using since 1986 to clean my motorcycles, cars and just about anything else.

On the armature, I used 320 grit and then 600 grit wet sandpaper. After that, cleaning the armature again to get rid of the grit and then wiping down the contacts with lacquer thinner.