So maybe we need try your tests?

Eg ignition switch changed but test again - you said power to pin of relay - you mean connect wire from ignition switch to relay pin?

Voltage drop test would be turn ignition check wire voltage at starter motor?

Anyway test starter solenoid? Note again sometime it will start after turn once eg turn off turn on try again so maybe not starter motor? But think can't buy solenoid separately?

Finally the ecudoctors said immobiliser fried ecu damaged so they repaired. Wonder any shorts that would cause this?

Yes very strange case - for example

After fit refurb dme immobiliser and new key set seems ok

But then yday after left overnight start car turns once stop, try again same thing

Lock car unlock try start no problem including later in day restart after stood for hours. But sometimes that doesn't work can't start. What we do is disconnect battery overnight retry 24 hours later then it's ok starts again
So it's not hot start plus temps here are 35c but never overheats

I think if turn once as you said not immobiliser it's either ignition key, starter wiring or starter and solenoid?

Your case sounds quite atypical. It sounds like your engine is hard to turn or the starter is at the point of seizure. One case I know is an N/A 996 the coolant fans high speed failed and that made the engine very hot and once parked and heat soaked, the starter seized and did not turn over. Fixing the fans fixed the hot start issue.

I wonder in your case whether your starter is the culprit. I think there's a switch to detect the park position of the car. Maybe you can move the shifter out of park and put it back and retry?

Also, do you have another key to try?

Have they performed any voltage drop test on the starter cable?

And big thanks for help! Pretty desperate coz never know if I get stranded or not when turn the key

Hey Ahsai

Car is a Tiptronic so not clutch switch. But we thought is there some tip shift mechanism that would cause this eg not recognise car is in park?

We changed ignition switch previously and tested seemed OK

Battery is a little over a year old - but note yesterday car after I relock unlock started straightaway - also later in the day I restart the car no problems

Yes checked relay think bridged olus swapped one time when the car just wouldn't start at all eg cranked once stops won't turn over more

That's what it does stops after one crank turn key back try again stops after one crank

But then lock unlock try again sometimes works! We thought mate dme key immobiliser so got that all refurbed but still same problem!

Which then leaves starter or solenoid? Note it often happens after long drive let car sit a few hours like somethings affected by heat soak

Anything else eg wiring fault? Though they said checked ground earths were ok

When you put the key in the ignition and turn it to the last position before crank, the immobilizer senses the RF pill inside the key fob and if it's happy and you push the clutch in all the way, the dme will activate the start lock relay to connect the ignition key (crank position pin) and the starter solenoid. Now if you turn the key to crank, the ignition key's power will be sent to the starter solenoid via the relay.

The fact that your start turns (even once) means all the above had happened. Now, why it turned once and stopped? There are a few possibilities:
- A weak battery
- clutch switch (you can just bridge the two pins to bypass it)
- ignition switch. Can test by removing the relay and supply power (with a fat cable that can carry tens of amps) directly to the relay pin that's connected directly to the solenoid.
- starter. Either the solenoid or the starter is bad. Will have to r&r to fix
- starter relay. Less likely as you said even bridging the relay didn't help

Hey Ahsai

Having major starting problems with my 996 TT

Read online you seems be expert with these cars and such problems

Car opens with key fob put key in ignition starter turns less than once stops

Take out lock reopen try again sometimes starts

Eventually happened all the time - garage advised change immobiliser refresh dme board

Did that - buy fault still there

Garage has tried bridging relays didn't work when car won't start

Any advice? Strange fault eg it's not that car won't turn - it turns a little then stop

Or that car turns won't fire

Grateful if you have any ideas - we are completely stumped!

Back and forth on repair dme immobiliser has lost me two months without the car already

Big thanks of you can help

Jonathan

Hey Ahsai - i wanted to check in and see how your replacement cats were working out for you. My Mechanic has some concerns about the Carnewell replacements but I have read nothing but good things about them. Are you still using them and are happy with them in California?

Jamie

Hi Ahsai,
Hope all is well. This should probably be added to the Sticky List.
Steve

Starter Cable replacement
https://rennlist.com/forums/996-foru...ter-cable.html
http://www.renntech.org/forums/topic...tage-problems/

http://www.ebay.com/itm/VGate-WiFi-O...-/321393253862

This is another I saw