Starting problem

[topgear253]

Hi

I've just developed a problem when starting my car in the mornings. The battery is only about a month old so it turns over perfectly but the engine doesn't fire up properly. Eventually when it does start it seems like it might be running on 5 cylinders and idles at about 500 rpm rather than about 1100. It's almost like the automatic choke isn't kicking in.

I then drive off and after a few mins driving, if I stop, turn the engine off, then on again, it starts as usual so it's clearly a cold engine thing.

As this has happened in the middle of Xmas I cant take this anywhere to get it looked at, can anyone advise me on this, and is it OK to drive in the meantime?

Many thanks,
Alex

 

[Richard_Hamilton]

Any sign of a "Check Engine" light? Coil pack(s) would be my guess, but a diagnostic test would be the first step.

 

[topgear253]

Sorry for the late reply Richard but in the following 4-5 days after my post the cold starting got gradually better until now it's fine again. There wasn't any warning lights but I'll keep monitoring it and see if it comes back again, particularly as the weather is meant to be colder in the next few days...

Cheers, Alex

 

[steveoz32]

Are you saying that the engine doesn't even turn when turning the key or it just will not fire?

If you pull the ignition relay it should still turn but will not fire.

The barrel is a known weak point IIRC.

 

[222lotus]

Steve,
Thanks for the fast post.
The problem is I turn the key and nothing. Not even a click! That leads me to think there is no power from the switch to the starter solenoid. But not being a 996 expert yet (though fast becoming more intermate with my 996) could it be something in between?
Steve.

 

[steveoz32]

No problem, are all other electrics working at key position 2, is it just the case that nothing at all happens when you move to position 3?

 

[steveoz32]

Where I was going with this is, that if the start solenoid has constant 12v from the battery and a good ground (which it sounds like it has and you have already checked), and you can not even here the solenoid clicking when moving to position 3 to pass current to the motor (and nothing else occurs, IE no dimming of lights or other strange occurrence to indicate another electrical issue) then it sounds like you aren't getting a live from the starter trigger or switch to the ignition. Is the earth on the motor ok?

It 'could' be that this trigger was damaged when the motor burnt out or something at that end occurred, just a guess though, as without having the old unit and looking at / testing it who knows what or why it went pop.

Here's something that may be of interest to you on the ignition relay topic you mentioned http://www.porscheclubgbforum.com/tm.asp?m=612019&mpage=1&key=ecu


Cheers,

 

[Richard_Hamilton]

The starter gets its signal from the DME, not the ignition switch itself, so as Steve says, worth checking the ignition relay and start lock relay. If one has burned out, I expect it will be pretty smelly if you unplug it and take a sniff.

 

[222lotus]

Steve, Richard,

Many thanks for the prompt replies. I will check out the the relays as you suggest and let you know how I get on.

Cheers
Steve

 

[222lotus]

Hi guys,

Found the relays no problem thanks to pics Steve. None had a burnt smell about them. Well it has been a few weeks since the starter motor went. Anyway the "black"ignition relay looked old so replaced it any way. I did try as suggested and bridge across and yes I got the engine to turn over but followed by the alarm cutting in. This did not stop until I locked and then unlocked the doors a few times. Got the new replay in the post today. Pluged that in and still no action when the key is tured to posiion 3. You seem to like a good brain teasing much as I do. My other toy is a Lotus. Starter trigger what is that? Can you point me to what I should be checking next.
Thanks in advance for you continued interest in my woes.

Cheers
Steve

 

[Richard_Hamilton]

If it turns over by bridging the relay, then you can eliminate the starter motor and its connections.

A couple of thoughts.

The ignition switch could indeed be faulty, and not signalling the DME. The switch contacts take virtually no load, but may have physically broken up inside. (DIY in the technical articles section).

The immobiliser could have cut in and is inhibiting cranking. Can you hear the fuel pump running for a second or two when you switch on the ignition? If not, it might be the immobiliser.

 

[steveoz32]

No probs, as Richard mentions, sounds like the control module is not activating the relay, hence when you bridged, it bypassed the switching function of the relay and manually forced the circuit to complete, again the immobiliser function would have stopped it from firing.

At this point it is likely that the issue is simply that there is no signal to tell the ECU that the key is in position three, the relay does not activate and therefore does not pass current or complete the circuit.

This could be an unfortunate co-incidence, or related to the failure of the starter and in some way the circuit was damaged.

Where about's in the country are you by the way? If anyone is fairly local and could pop down and plug a durametric or similar in, it would be handy to see if there is anything else a-foot. If it is a simple malfunction of the ignition switch or similar though then this won't be picked up (as it isn't actually an error, it's just not even activating therefore as if the key has not been turned).

I understand your frustration, it took me quite some time to locate my starting issue when I got my 996, I just about tested all of the fueling system, even removing the pump from the tank! Then moved on to the ignition system before finally taking an educated guess on the crank sensor and thankfully it worked! There were a long list of things I had to eliminate first though!


Good luck!

 

[222lotus]

Steve, Richard,
Thanks for all the help. At least I now know that a number of the components I have changed so far will be good insurance for the future.

I am in South Essex and was going to ask does anyone know a good mobile auto electrician in the area.
If not then will need to get the car recovered to a workshop where I have had the car serviced. I am getting to the limits of what I can test.

Thanks again. Will report back when and how we get it working again.

 

[222lotus]

Hi,

Well it was the O/side vario cam adjustment solenoid which had a short circuit and then finally burnt out. The guys at Daniel James (my local indy ) said it was quite rare. In fact he could not remember the last time he had seen one go. Anyway got them to replace both sides on the basis if one had broken down the other side might not be that far behind. So to replace them they had to remove both exhaust manifolds which was a pain as they seemed to be the originals and rusted on solid. The car is now back to rude health and my wallet somewhat lighter.

Steve

 

[Richard_Hamilton]

I'm pleased to hear you got it sorted Steve.

I have heard of the wiring loom to the Variocam solenoid shorting out, which blows the DME fuse and prevents it starting. Unusual for the solenoid itself to go short circuit - they normally fail open circuit, which just gives rough running.

 

[222lotus]

Richard,

For info. The guys told me that they had found the fuse had blown. They replaced this and the car started OK. After a few moments their workshop started to fill with smoke. They turned it off and got the car up on the lift. The smoke was coming fron the solenoid. Not something they had seen before!

Steve