urgent help needed. boxter 3.2 cutting out
 

Hi.
i need help with a 2003 boxster s. the car suddenly started cutting out after a battery change a feeks ago, it made it 250 miles before it started playing up. i have checked it for trouble codes and nothing found, i have changed the dme and the starter relays, checked 9 earth points, been through as much wiring as possible and found nothing, checked the alarm module for water ingress and no faults there.
The car will now start and sometimes tickover and run perfectly for maybe a minuite, an hour or half a day then it just stops and wont turn over or power the engine circuite up at all.
ive checked the ignition switch again with no faults.
im really sure its suddenly loosing a power supply but where does the cars interior electrics powered from?
Ive traced the one and only one main battery lead through the bulk head, under the centre console and through the rear fire wall where it connects the the starter motor lead, but cant find any where were a junction or tee off is to power the fuse box, ignition ect.
has anyone any ideas?
the lights, radio and all other auxilleries stay powered up.
Help me pweeese. :((((

2 thoughts
 

1. Ignition switch - a $15 swap out

2. Battery or alternator - test charging circuit, battery voltage with car running 3k RPM and not running

Both covered on my web site

It sounds like you've checked a lot of stuff, so I hesitate to even mention this, but if it were a motorcycle, those would be classic symptoms of a loose battery cable, at the battery. (I wrench on motorcycles for a living). Again, with the amount of wiring you've checked out, you've probably checked the terminals about 10 times, but give em a good tug if you haven't : trying to wiggle the cable side to side with your hand. It shouldn't move.

nope none of that helps.
 

yer checked all the battery leads 30 times i think..lol.
i really need to find where the car gets its auxillery power from, there must be a t off or junction box somewhere from the positive battery lead but im buggered if i can find it.
the cars charging system is fine.

Hi. i have spoken to a local porsche dealer and they tell me they have come accross the same problem with a identical vehicle and had to fit an ecu at nearly £2000. oops.
Well ive put it back together now and given up.
And guess what.
It wont even bloody turn over now unless i leave the ignition on for 15 mins first then you hear all the enging components burst into life, ya turn the key and it starts and runs perfectly.
im at a loss as to what to do with it.

still not cured it,,im buying a ford..lol
 

Well the suns out and i still cant use the bloody car.
Its been starting perfectly for the last 2 weeks showing no faults at all so i decided to venture out the drive with it and go on a 1mile, then back then a 3 mile and she ran perfectly,,,
Until i decided to venture that little further, about 8 miles then it suddenly cut out and wouldnt even crank over.
Left it for 20 minuites and it started, got me home and now am back to square one.
at the moment it is starting and running as good as gold.
I still need help.

Not sure I can be of much help from 4000 miles away, but I will offer a suggestion: swap the battery, again. I know you just replaced the battery, but it very well could be the cause of your problem.

I had the battery go bad in my little runabout motorboat this Spring and it caused issues very similar to what you are describing. I didn't dissect the battery to confirm, but I am convinced it had a bad connection from the final cell to the positive terminal. If I hit the battery in just the right way, my boat would start. Otherwise nothing. I re-did the ends of the cables connecting to the battery with nice shiny new parts -- no joy, still intermittent problems. I finally replaced the battery and the boat works flawlessly now.

Good luck.

maybe its the alarm system immobilizer acting up?

:mad: thanks for the replys but it aisnt the battery as i have the originalback on it which is fine.
The alarm system once depowered and the engine is running shouldnt be able to kik back in.
im at my wits end and its doing me head in coz i cant find the fault.
Im also still struggling to find where the car gets its ignition feed from as i cant find a feed from the main battery terminal or lead anywhere.
and while it wont play up i cant do any more testing on it as its running fine.

When the car stalls, are the electonics in the car (radio, hvac fan, etc) still on, or do they shut off also?

If its just the engine shutting off, I would recommend disconnecting the MAF sensor, and driving around with it off, to see if that might be the cause somehow.

If everything dies, check the connections on the alternator.
Loosen them, retighten them, and add some die-electric grease to protect them.

BC.

Hi.
Thanks for the reply.
Everything in the car stays powered up.
The engine just cuts out as if you have turned it off but everything is still live.
i dont think it will be the maf sensor as no trouble codes are stored and when it does start and run its perfect.

Ahhh... I misunderstood your earlier posts, then. A few other ideas.

You've change all ignition related relays, right?

Could be the fuel pump. I've had past cars with fuel pumps that just quit randomly only to start working again for a short while. If this is the problem, it would start to run poorly for a few seconds as fuel pressure dropped and then cut out.

Or it could be the DME (as a service center suggested to you) from a bad solder joint or flaky component on the circuit board. Do you know of anyone else with the same year S nearby? Maybe they could loan you their DME when they are on holiday so you can do some extended driving to see if the swap cures your car's problem.

There are other potential culprits, but these two are very likely.

~~~~~

Nevermind the above suggestions... I just re-read your original post. It stops running and won't even crank to restart. Sure sounds like an electrical issue that is cutting off all power to ignition and the starter. Ground straps? (... but you checked those). I don't have any good ideas that fit your symptoms. Sorry.