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Location: San Diego
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Cylinder Head Temp Sensor
Hi gang,
Does anyone know if a CHT sensor can fail or partially fail without throwing a trouble code? I was so certain that was my problem, but even checking with a hammer shows no codes. Thanks
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Chuck 90 C2 78 911SC 79 911SC |
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05-01-2009, 04:50 PM
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Why do you think it has failed? Is it hard to start when it is cold?
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Stan D |
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05-02-2009, 10:57 PM
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Yes, it is hard to start when cold and has a hesitation just off of idle. Then some days there is a short period when it is warming up that it runs great. Then when it reaches operating temp it has the hesitaion again.
I have cleaned the ISV. That helped some. I did the Air Flow Meter wiring TSB. That did nothing but needed to be done anyway. I changed the O2 sensor. That helped a little. Replaced a bad coil. That helped an amazing amount, but there is still that annoying hesitation that makes it not fun to drive. Thanks
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Chuck 90 C2 78 911SC 79 911SC |
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05-03-2009, 06:52 AM
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I'd bet $10 it is the CHT
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Don Plumley M235i memories: 87 911, 96 993, 13 Cayenne |
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05-03-2009, 10:41 AM
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Can't say it will fix the hesitation but it should help with the starting. Its easy to swap and not expensive so its worth changing it.
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Stan D |
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05-03-2009, 01:35 PM
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Yea, I'm thinking I'll just change it to rule it out if nothing else.
Thanks Guys
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Chuck 90 C2 78 911SC 79 911SC |
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05-04-2009, 07:33 AM
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Chas911 .. what was the outcome?
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04-13-2011, 05:34 AM
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It worked a little, but I still have a slight hesitation and when I start it from cold I have to start it at least twice before it will stay running, and even then it runs on about three cylinders for a few seconds. I am now suspecting maybe fuel or fuel pressure at start. That doesn’t work for the hesitation though. I’m wondering if maybe it might be plugs or wires so I’m going to replace those at my next valve adjustment which should happen soon. I also still wonder if it isn’t a vacuum leak somewhere but I sure can’t find one.
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Chuck 90 C2 78 911SC 79 911SC |
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04-13-2011, 03:04 PM
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My car started much better after changing coils
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04-14-2011, 07:22 AM
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I have tried this ... problem still persists ...
- new ISV - Steve Wong chip - new coils - new fuel filler neck & cap - checked for vacuum leaks - new air filter - cleaned AFM - fuel injector cleaner fuel additive - new oxygen sensor |
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04-14-2011, 01:26 PM
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you had a bad coil originally? ive seen bad coils damage the ignition control modules something you may want to check but doesnt sound like thats your problem, did you check the boot that goes between the manifold?
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04-22-2011, 01:06 PM
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i have seen those cht sensors act up on a carrera 3.2 engine. i have a new sensor for a 964 engine for $50.00 if that will help you regards tom
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04-22-2011, 01:12 PM
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1987 Porsche Carrera 3.2 
