964 Alarm issue

[Porscher]

Hi guys!
I have aproblem with my 964 that I don't know how to go forward with.
Hopefully the community can point me in the right direction.

It started a couple of weeks ago when engine wouldn't crank. Everything lit up in the cabin and you hear the fuel pump engaging but when you twist the the last twist to crank nothing happens. I also need to say that a week prior to this I smelled the familiar smell of burnt cable for a short second or two while in the garage doing some other stuff to the car while passing the passenger side of the car. It was just a short second and then it disappeared, did I imagine this? Didn't think of it anymore.

So I figured maybe the starter was bad since I measured that I had voltage to the starter but no crank. So I connected a wire to it and put other end of wire to the battery and sure, it cranked. So not the starter. It's almost new aswell so it was not so likely.

Do I have a bad ignition? So I did the wonderful job of removing the ignition(those who know knows). The ignition was almost brand new aswell but I tested with a second one and it didn't work either so ignition is good. I also tested continuity on the wire that goes from ignition to starter and offcourse that worked since I allready tested voltage at the starter earlier.

That gives me the conclusion that it's an alarm issue. I know nothing about alarm but I've read a few threads about it and as far as I can see I have no relay behind the passenger side bonnet hinge. I have an alarm under the passanger seat. I've checked the fuses off course early on(first thing I checked) but can't se anything off there. The alarm has been acting stupid going off and on sometimes. The doors locks thems self after a while being unlocked(did these cars have that from factory?)

So does anybody have a direction point me to?

Tnx in advance.
Best regards Ola

[Porscher]

[Porscher]

Trying to upload pictures but unable. Red marker on yellow wire is cable from ignition.

[mysocal911]

Originally Posted by Porscher

Hi guys!
I have aproblem with my 964 that I don't know how to go forward with.
Hopefully the community can point me in the right direction.

It started a couple of weeks ago when engine wouldn't crank. Everything lit up in the cabin and you hear the fuel pump engaging but when you twist the the last twist to crank nothing happens. I also need to say that a week prior to this I smelled the familiar smell of burnt cable for a short second or two while in the garage doing some other stuff to the car while passing the passenger side of the car. It was just a short second and then it disappeared, did I imagine this? Didn't think of it anymore.

So I figured maybe the starter was bad since I measured that I had voltage to the starter but no crank. So I connected a wire to it and put other end of wire to the battery and sure, it cranked. So not the starter. It's almost new aswell so it was not so likely.

Do I have a bad ignition? So I did the wonderful job of removing the ignition(those who know knows). The ignition was almost brand new aswell but I tested with a second one and it didn't work either so ignition is good. I also tested continuity on the wire that goes from ignition to starter and offcourse that worked since I allready tested voltage at the starter earlier.

That gives me the conclusion that it's an alarm issue. I know nothing about alarm but I've read a few threads about it and as far as I can see I have no relay behind the passenger side bonnet hinge. I have an alarm under the passanger seat. I've checked the fuses off course early on(first thing I checked) but can't se anything off there. The alarm has been acting stupid going off and on sometimes. The doors locks thems self after a while being unlocked(did these cars have that from factory?)

So does anybody have a direction point me to?

Tnx in advance.
Best regards Ola

The alarm ECU doesn't control starter. The starter signal (#50) from the ignition switch goes directly to the starter.
It's only the 964 automatic where the #50 from the ignition switch goes thru the transmission ECU.

[Porscher]

Originally Posted by mysocal911

The alarm ECU doesn't control starter. The starter signal (#50) from the ignition switch goes directly to the starter.
It's only the 964 automatic where the #50 from the ignition switch goes thru the transmission ECU.

Ok so you mean it has to be a starter or ignition problem?

[mysocal911]

Originally Posted by Porscher

Ok so you mean it has to be a starter or ignition problem?

You already made the starter function in post #1. You need to trace the #50 wire from the ignition switch. Did you check for a starter relay in the fuse box?

[Porscher]

Yes I did check the fuses. No starter fuse as far as I can see

[deckard]

when you say everything lit up in the cabin are you referring to the 'christmas tree effect' of the warning lights? my 964 did exaclly this and the problem was the ground strap at the battery.
it looked good, was original which means copper, and it didn't work properly.
i had already changed the strap underneath the car which meliorated my crank problem somewhat but it came back until i changed the strap at the battery which fixed it completely.

[mysocal911]

Originally Posted by Porscher

Yes I did check the fuses. No starter fuse as far as I can see

starter RELAY

[Porscher]

Originally Posted by mysocal911

starter RELAY

Yeah I wrote fuse but I meant fuse and relay. Didn’t find anything that would be associated with the starter

[Porscher]

Originally Posted by deckard

when you say everything lit up in the cabin are you referring to the 'christmas tree effect' of the warning lights? my 964 did exaclly this and the problem was the ground strap at the battery.
it looked good, was original which means copper, and it didn't work properly.
i had already changed the strap underneath the car which meliorated my crank problem somewhat but it came back until i changed the strap at the battery which fixed it completely.

I meant light up as usual, except from the oilcooler fan that starts up a few seconds and then quite down again. Can't remeber that it did that earlier.

[mysocal911]

Originally Posted by Porscher

Yeah I wrote fuse but I meant fuse and relay. Didn’t find anything that would be associated with the starter

For troubleshooting the yellow starter wire (#50), you can jumper the yellow & big red wires at the starter.
Then you can use a testlight to determine where the starter wire is missing in the front near the ignition switch.
This is done with the ignition key in the off position.

[Porscher]

Originally Posted by mysocal911

For troubleshooting the yellow starter wire (#50), you can jumper the yellow & big red wires at the starter.
Then you can use a testlight to determine where the starter wire is missing in the front near the ignition switch.
This is done with the ignition key in the off position.

I've testet the yellow wire for continuity, shouldn't that be enough? It's most likely ok.

[mysocal911]

Originally Posted by Porscher

I've testet the yellow wire for continuity, shouldn't that be enough? It's most likely ok.

Continuity testing has limitations! Sounds like it's time for a repair shop. Good luck.

[Porscher]

Originally Posted by mysocal911

Continuity testing has limitations! Sounds like it's time for a repair shop. Good luck.

Yeah I think you're right. Tnx for your inputs, appriciate it.

[911obgyn]

Clean your ground strap at battery also.
I had a no start checked starter and cleaned terminals everywhere now it starts fine.

[Porscher]

Originally Posted by 911obgyn

Clean your ground strap at battery also.
I had a no start checked starter and cleaned terminals everywhere now it starts fine.

Yeah been thinking of that too. It's the next thing to do I guess.

[hienz]

get in the car.
turn on the ignition key.
lock the door using the switch then unlock the door using the switch.
Now you can start the car because the alarm system disabled the engine from starting up to
prevent thief.

[Porscher]

Originally Posted by hienz

get in the car.
turn on the ignition key.
lock the door using the switch then unlock the door using the switch.
Now you can start the car because the alarm system disabled the engine from starting up to
prevent thief.

Tried this but couldn't unlock it from inside?🤔 alarm went off and no difference otherwise

[speedster911]

By chance when you try and start your car, is the trunk lid , engine lid, glove box door etc open or closed securely?

I experienced a similar no start issue when I first got my car. I could also hear my alarm module clicking, so perhaps different issue.

I disconnected the battery and let it sit for a couple of days, cleaned terminals before reconnecting and made sure all open compartment/lids/ doors were closed. Started right up.