mattblack

The car. 2008 911 Carrera 4S 34k Miles on clock started this problem at 24k miles :-( spent a small fortune and a car a hardly drive now because of the stress. I rather drive the Range Rover and thats shocking to say with the money I spent on the 911..

Problem..

Car fires up on cold start - Great Smile

Warm start say I drive for 10 mins park up and then restart its struggling like mad to startup, so bloody embarrassing pulling up in a flash car that sounds like a coughing dog when starting up.. Sound like a dead battery wrrr wrror worrr worrr worr then starts and sometimes I have to turn car off then try again in 5 mins


These are the actions I have had done in order to get this fixed and failed

1. wiring harness with connection point generator starter Part number 997-607-019-03 ("alternator/starter harness", "alternator/starter cable loom") replaced last year

2. Battery Earth Cables all over

3. New Battery

4. All the coil packs

5. New Starter Motor (helped for 1 week and problems back)

6. Part number 997-607-019-03 ("alternator/starter harness", "alternator/starter cable loom") replaced again.

7. Crank shaft sensor was replaced April 2015 temporarily made problem better but not fixed..

8. Now worse than ever

semicycler

Wow, you replaced all the major items except the alternator. Are you throwing any OBDII codes? Are you DIY'ing this or working with a shop?

mattblack

Porscheuro in Barnsley http://www.pecarspecialists.co.uk/ guy called John he is so nice. Alternator been tested and he says its fine.

@semicycler you think i should go for a new alternator ?

Dropping car off tomorrow again as sick as fk with it.. :-(

Macster

Time to find a young priest and an old priest...

Uh, on a more serious note, the behavior suggests either a crankshaft position sensor or a fuel pump, or fuel pump relay.

You replaced the crankshaft position sensor and the car got better but not for long. That could have just been the fuel pump being on its best behavior for a spell.

There have been cases of a bad dual mass flywheel causing problems as the flywheel has too much play and this play causes the crankshaft position sensor signal to the DME to be unacceptable.

Not enough to go on to justify removing the tranny to check the DMF. Not even enough to go on to justify replacing the fuel pump. You can throw a new fuel pump relay at the symptoms.

That's all I have. I can't think of what else it could be unless of course it does turn out to be something that does require a couple of priests...

Added: I note you have a 4S. These models (along with the Turbos) have a goofy/complicated fuel supply system that has siphon jets to pull fuel out of the unconnected -- at the bottom -- basins one on each side of the front axle diff/driveshaft. If one of the hoses inside the tank has a crack or a split this can result in no fuel delivery. Not sure how turning off the ignition and waiting 5 minutes though could "fix" this. This behavior then leads me to believe the problem is electrical or electro-mechanical in nature and this points to the fuel pump (or fuel pump relay) or the crankshaft position sensor (or DMF).

Ahsai

When it's struggling to start, does the starter spin slower (struggling) or it spins fast but engine just won't catch?

Have they checked the fuel pressure and flow rate? Do you know what other troubleshooting they did?

Was the "new" starter brand new or it was a reman?

gumbyaz

Highly interested in this because my 07 C4S displays similar symptoms, although not quite as bad as OP. I am just starting to plan out my path to fix it.

I read in another thread somewhere about a guy that fixed his by re-crimping the lug end of the alternator cable where it attaches to the starter using a $50 hydraulic crimping tool. Anyone else ever heard of this? Makes sense if the root of the problem is truly a poor electrical path from battery to starter motor.

mattblack

@Ahsai sounds like a slow as hell spin - brand new starter - my indi is keeping a eye on this thread :-)

Wayne Smith

Thank you for this Macster ... I am totally stealing this line for future use!

Ahsai

Ok, in that case the standard troubleshooting should be to verify:
- battery health
- charging system health
- voltage drop test on BOTH the positive and ground side between the battery and the starter. Note there are multiple segments of cables between the battery and the starter and each segment and their connections will need to perfom well. Also, the voltage drop tests have to be done at the time when the fault occurs to catch the culprit.

All the shops should know the above anyway so I'm not sure I'm helping and that's why I asked if you know what kind of troubleshooting they have already performed.

If they have done all of the above, I would wait for the condition when this fault will occur and then remove the serpentine belt. Then hand crank the engine, alternator, a/c compressor, steering pump, etc. everthing riding on the belt and see if anything is hard to turn. It's hard to imagine anything that could load up the starter that much though but it's easy to do and verify.

jchapura

I was gonna suggest a slight variant - a young priestess with a voltmeter but you guys beat me to it.

josephmonaco924

My 06 997.1 has been doing same thing since new to me. Once read this is somewhat normal. Mine starts every time but does feel like battery is dead.

semicycler

I wouldn't just yet. It does sound electrical but you report the alternator is fine and the car starts fine when cold. I'm assuming the battery is holding it's charge too. It's only when warm there's a issue. If the alternator was bad your battery would drain and the symptoms would remain after the car cools.

First I'd want to know the codes being thrown from either PIWIS or Durametric. Those generic OBDII readers can miss some of the Porsche specific codes.

Are you getting misfires? Coil packs were changed, good. What about plugs? I've heard of weird misfire issues with plugs only when warm, rare but it happens. Something about the ceramic was loose and would act up only when warm. Doesn't explain why your starter lugs when warm though.

I like Ahsai's idea of pulling the serpentine belt when warm and spinning all pulleys by hand. Maybe something is seizing up when the engine is hot? AC clutch perhaps? Turn off your AC as a test too (just a random thought). Also test the starter in this case with the belt off.

The only other thought is to try and isolate if it's the starter or something else. Maybe try push starting the car when the symptoms show up. If a push start starts the car fine but it fails with the starter that would be a huge clue.

DC911S

There are two cables for the battery to starter circuit. One cable goes from the battery to a junction box under the car. At that location there is a bus bar like connection that bolts to it. The second cable goes from that bus bar connection to the starter, they are two separate cables and pretty sure two part numbers. I just had mine replaced and it cured my hot start problem. Find out which cable they replaced and if they checked the voltage drop at the right locations.

Philster

My hunch is that some of the work was not done properly.

Simplest explanation: You have the easy cold / hard warm start with the drop in cranking strength and 1 and 2 (plus 5 bonus) should have solved.

The work listed, and the parts listed in steps 1 and 2 are in question.

This is the most likely issue, and it should be addressed first. Work down from this; save all guess work until work and parts in 1 and 2 are triple checked.

.

mattblack

Hi Guys

Thanks for your time writing tips, i have dropped the car off with the INDI and give him this thread url..

Keep you all updated...

Thanks

Matt