Ignition problem: random lag in ignition

[deusexmachina]

Hello,

 

I own a 2004 911 4S at ~70K miles. There is an ignition problem that the mechanics were unable to diagnose.

 

The symptom is, *sometimes* when I turn on the ignition the car won't start right away. Sometimes I have to hold down the ignition for a few seconds and other times almost half a minute. As I said, this happens intermittently, since they could not replicate it consistently they were unable to pinpoint the cause.

 

When I am holding down the ignition, I hear no activity in the car (no cranking of the engine, etc.) other than some faint electrical noises which I assume the AC and maybe something else. Once this happens I realize that it is more likely to happen consecutive times as well then car goes back to normal randomly. Also there might be a correlation with cold weather but it happens in warm weather too. Another thing I realize is, if I try to turn the ignition right away after bringing it to stand-by, there is always a lag.

 

So far I had the ignition assembly replaced and battery changed but no avail. This is a big annoyance for me and I am even considering selling the car because of it. And ideas? I am more than willing to pay for a good diagnosis :)

[JFP in PA]

Hello,

 

I own a 2004 911 4S at ~70K miles. There is an ignition problem that the mechanics were unable to diagnose.

 

The symptom is, *sometimes* when I turn on the ignition the car won't start right away. Sometimes I have to hold down the ignition for a few seconds and other times almost half a minute. As I said, this happens intermittently, since they could not replicate it consistently they were unable to pinpoint the cause.

 

When I am holding down the ignition, I hear no activity in the car (no cranking of the engine, etc.) other than some faint electrical noises which I assume the AC and maybe something else. Once this happens I realize that it is more likely to happen consecutive times as well then car goes back to normal randomly. Also there might be a correlation with cold weather but it happens in warm weather too. Another thing I realize is, if I try to turn the ignition right away after bringing it to stand-by, there is always a lag.

 

So far I had the ignition assembly replaced and battery changed but no avail. This is a big annoyance for me and I am even considering selling the car because of it. And ideas? I am more than willing to pay for a good diagnosis :)

 

If you have already replaced the ignition switch, I'd check the car's main grounds (starter/alternator circuits) for excessive voltage drop (sign of corrosion/bad connections).  You should be able to find a DIY using a simple multimeter.

[AWDGuy]

Would a worn out key cause any of this?

[Ahsai]

If it's a stick shift, also check your clutch interlock switch. When the no-crank happens next time, just put the car in neutral, remove and short the two terminals on the switch and try to crank.

[JFP in PA]

Would a worn out key cause any of this?

 

No, but a lack of commuinications between the pill in the key and the alarm module would do it.

[deusexmachina]

Hi all,

Thanks for the recommendations. I forgot to mention that I already tried a new key. As for the clutch (yes it is a stick shift) I believe they checked if it was worn out but I will ask again.

Is there a way to get a diagnosis log from the computer, etc. to see what happened when this happens next?

[Ahsai]

Hi all,

Thanks for the recommendations. I forgot to mention that I already tried a new key. As for the clutch (yes it is a stick shift) I believe they checked if it was worn out but I will ask again.

Is there a way to get a diagnosis log from the computer, etc. to see what happened when this happens next?

 

Most likely nothing will be logged in the computer since the starter does not even start. Being intermittent is not easy to diagnose.

In addition to the clutch, there's also a start lock relay behind the rear seat, and the starter itself that may act up but those are harder to access, especially when you need to catch it when it happens.

 

My reco is still like my previous reply. Familiarize yourself with how to unplug the clutch switch (it's gray). Just jump the connectors WHEN it happens next time to see if it helps.

 

Note even they tested the switch, since the failure is intermittent the test was inconclusive.

Edited September 12, 2014 by Ahsai

[deusexmachina]

I ordered a new clutch switch. I will let you know how it goes. Thanks for the advice.

[Ronnie38]

I had a no start problem, I jumped the start relay "placed a jumper wire across it" starter ran but still no start, tracked it down with multi-meter, found the Immobilizer not working, sent the unit under the drivers seat to be repaired. problem solved