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964 difficult to start from cold

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Old Nov 12, 2007 | 05:30 PM
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Default 964 difficult to start from cold

Hi guys,

I have recently purchased a 964 and I am having difficulty starting it from cold. When I start it, it will run for a second and then cut out. I have changed the DME relay for a new one as I have heard that these can be problematic. This did not cure the fault. I have since found out that it will start first time if spraying a squirt of carb cleaner in the inlet. Once started and warm it runs perfectly and the performance is perfect, and it will happily restart. This leads me to think it is some kind of cold start sensor or seventh injector. I have searched the net and cannot find any kind of data for this or if there is one fitted. As I am new to the model I am unfamiliar with the system. Any Ideas or info would be greatly appreciated!

Many thanks

Ian
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Old Nov 12, 2007 | 05:40 PM
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There is no seventh injector on the 964 3.6l engine.
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Old Nov 12, 2007 | 05:43 PM
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Ian ,
There is a head temperature sensor mounted at the top/front of the LH head .
If you had diagnostic kit to read the temp . value that would tell you if the sensor was plugged in , broken wire .

Find the sensor and take a look .

Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
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Old Nov 12, 2007 | 06:02 PM
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Thanks for the quick replys!

I shall have a look for the head temperature sensor. The aircooled thing is all new to me. I guess this works in a similar way to a water temperature sensor.

Is there a link to any technical info for this problem or this model? I cannot seem to find books or any info on the net anywhere, - well until now!

Thanks again

Ian
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Old Nov 12, 2007 | 06:12 PM
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Adrean Streather's Porsche 911 Enthusiast's Companion: Carrera 2, Carrera 4, and Turbo 1989-1994 is a good place to start. Lots of good info there.

Also, the CHT values (with out a diagnostic reader) are:

0 degrees C = 4.4-6.9 k-ohms
15-30 = 1.4-3.6 k-ohms
40 = 1-1.3 k-ohms
80 = 250-390 ohms
100 = 160-210 ohms
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Old Nov 12, 2007 | 06:23 PM
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Is this the sensor I am looking for?

http://www.pelicanparts.com/cgi-bin/...er=93060601302

Regards

Ian
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Old Nov 12, 2007 | 06:25 PM
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Thanks I shall check the reading with a meter

Regards

Ian
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Old Nov 12, 2007 | 07:19 PM
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Originally Posted by Ian964CAB
Is this the sensor I am looking for?

http://www.pelicanparts.com/cgi-bin/...er=93060601302

Regards

Ian
That's the one.

Here's a pic . . . looking in to the left rear wheel well, engine to the right, O2 sensor wire in the right hand side of pic . . . I'm not sure who gets the credit, but it's one of the many useful folks around here.
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Old Nov 12, 2007 | 07:26 PM
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Fantastic!

Thanks again for the help!

Ian
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Old Nov 12, 2007 | 09:10 PM
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Ian,
I would also check / clean the ISV and make sure that there are no obstructions in the pathways. This is easy to do and sometimes it works wonders.
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Old Nov 12, 2007 | 11:13 PM
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Originally Posted by dfinnegan
. . . I'm not sure who gets the credit . . .
Hey, that's my rusty engine tin.

Marc
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Old Nov 19, 2007 | 06:22 PM
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Well I went for a new sensor and it started first flick of the key! Thanks to everyone for your help.

One point to note is that the 964 part is no longer available and is now the same as the 993. For this sensor to be fitted fit the connector on the wiring also needs to be changed.

Now just the spoiler and the intermittent open/close of the roof to sort!

Ian
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