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98A4TQ
11-28-2009, 01:17 PM
After the car was sitting for the thanksgiving holiday I had to work today. it wouldn't start. The car smelt like it was getting fuel while it was turning over. I didn't have time to mess with it at the time. So I get home and have my wife turn it over for me. I don't see anything out of the ordinary. I check for exhaust pressure coming out of the back while she's cranking and that's good. I take out the spark plugs and they are flooded so fuel is there. What should I check next. Thanks.

Seerlah
11-28-2009, 01:25 PM
Maybe the cam positioning sensor?

Did you pull any intermittent codes? If you have a VAG Com, you may have a code that will lead you in the correct direction. But since you never had the car fully running, then you would not see a CEL. But yeah, leave the car in the starting position and scan for codes.

98A4TQ
11-28-2009, 01:43 PM
Yeah no CEL will vagcom for codes as soon as I get home. Thanks.

98A4TQ
11-28-2009, 05:06 PM
no fault codes found. Thursday when I parked the car in the garage I left the keys in the ignition. I grabbed them out through the driver side window Friday, maybe I damaged the ignition switch in some way by possibly not pulling the keys out straight. The Ignition does seem kinda loose now. could also be my mind playing tricks on me.

walky_talky20
11-28-2009, 09:45 PM
Next things I'd check would be coolant temp in vag-com (measuring block 003 or 004 as I recall) - make sure it is reading ambient, and check for spark. Pull a coil pack and stick either a screwdriver or a spark plug in the end and have someone crank it.

98A4TQ
11-29-2009, 08:52 AM
so I checked for ambient coolant temp and that was good also pulled a spark plug and checked for spark whick seemed strong. So I had air,fuel and spark. So I decided to crank it and it sounded like it wanted to start. I gave it a little gas on/off the throttle like a old carburator and it got stronger and stronger and then fired up. a bit of smoke from the flooded plugs but it smoothed out completly. I shut it off and it restarts fine. now im confused.

dangerous_dave
11-29-2009, 01:30 PM
Change the CTS and plugs. The CTS is bad making the ecu think it's colder outside than it is making the car dump a ton of fuel.

walky_talky20
11-29-2009, 04:04 PM
^ X2. That's my theory too. It seems like the CTS goofed up once, causing it dump way too much fuel initially. I'd change the CTS, and new plugs are probably optional, as long as it is running good now.

98A4TQ
11-30-2009, 05:25 AM
Ill do that, the CTS is probably the only part not new on this car, I've changed just about everything else. Thanks.

98A4TQ
12-25-2009, 03:09 PM
at the request of a PM I am following up on this thread.

To answer your question of a problem resolution, all I can say is that I changed out the CTS and this type of problem never happened again. But I couldnt say for sure if the CTS was the problem or It was something else.

fbdohc
12-26-2009, 03:08 PM
CTS = Coolant temp sensor ?

walky_talky20
12-26-2009, 03:17 PM
CTS = Coolant temp sensor ?

Correct. On 1.8T's it lives in a plastic flange at the back of the cylinder head.

dangerous_dave
12-26-2009, 04:24 PM
Correct. On 1.8T's it lives in a plastic flange at the back of the cylinder head.


And to elaborate on this, it is a black d shaped sensor if it has never been changed before or a green d shaped connector if it has been changed before. Make sure you get a new o ring for it and buy a new plastic clip for it in case you break or lose the old one taking it out. If it's never been replaced before the clip will be in backwards because that's how the rocketscientists at Audi put them in from the factory.

fbdohc
12-27-2009, 12:43 PM
Correct. On 1.8T's it lives in a plastic flange at the back of the cylinder head.
so what is the sensor that is in a coolant under the car ? the one you have to unplug to flush the coolant ?

walky_talky20
12-27-2009, 02:15 PM
so what is the sensor that is in a coolant under the car ? the one you have to unplug to flush the coolant ?

That is NOT a sensor. It is a "dual thermal fan switch". It is a temperature switch, actually 2 temp switches in 1. There are 2 temperature thresholds. The first closes, turning on the low speed cooling fan. The second threshold enables the cooling fan's high speed relay.

It is confusing because this switch is exactly the same dimensions and shape as the CTS, and even uses the same electrical connector. More than 1 member on here has found out that they have unknowingly replaced this switch with a CTS. The consequences of this is simply that the cooling fan runs constantly. No codes or other problems, other than possibly shortening the life of the fan.

fbdohc
12-28-2009, 03:05 PM
Thanks a lot , now its clear :D

tar
12-28-2009, 03:20 PM
i had same problem a few months ago. problem seems 2 have resolved its self.

dangerous_dave
12-28-2009, 07:21 PM
i had same problem a few months ago. problem seems 2 have resolved its self.

Highly doubtful. Your issue is an intermittent short in the CTS. You should replace your too because it will probably happen again at a very inconvenient time.


Coolant temp sensors give off two signals. 1 to the ECM and the other to the instrument cluster. If you dont have a fault code in one, you probably have a fault in the other.