# Cold start problem!!!



## juman20 (Jan 14, 2012)

hello I have a 00 TT and ive been having some cold start problems for the past month I had 11 codes all on emission and it was because of a blown fuse #34 after I replaced the fuse all codes went away and it would start fine but now every week or so it will misfire on cold start and give me the same problem when the fuse was blown except the fuse is not blown this time I replaced plugs and coils and nothing changed to get it to start I have to try it a couple of times and mess with the fuses like pulling them and putting them back then it somehow starts fine if anyone has ever encountered this problem please help me. p.s. as long as the engine is warm it will start every time with no probs.


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## gogs (Dec 22, 2010)

I had similar starting symptoms when my temperature sender was on its way out! Started fine when warm but was murder when cold, several attempts, sometimes started then stalled, have you noticed any issues with your temp gauge ?


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## juman20 (Jan 14, 2012)

are u saying it was ur temp sender? did u resolve the problem? my temp gauge has alsays sat a little past half even after replacing the thermostat sometimes it will go up to 3 quarters and go back to half but ive read that thats a common problem with the dash on the early tt's


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## Hoggy (May 8, 2002)

Hi Juman, Temp sensor has 2 outputs its possible its giving wrong temp to ecu & giving a cold start, warm start temps & causing weak mixture. Temp gauge usually sits at 90 but can rise above when stationary, especially if aircon off.
Hoggy.


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## straut (Aug 31, 2011)

Hi juman20,ok i can only give you my story from when i first got my TT so here goes.
When i first got my car sometimes it would misfire from cold start just when the revs were coming to rest 
i got a few codes
first one pointed to temp sender
i also got a maf error code but the car ran exactly the same if i disconected it
and my car was only running at 60 or 79 degrees (should be at 90)
so what happend was

1,changed thermostat
2,changed temp sender
3,changed maf sensor
cleared codes and it took a bit of time but eventualy the cold start problem cleared altogether and is now spot on and has been now for 2,000 miles
Loads of people have had this problem and there seems to be no definitive answer so all i can recomend is read any codes and take it from there but i dont think it is anything serious
incidently the car ran perfect apart from the cold start miss
steve


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## juman20 (Jan 14, 2012)

hoggy: thanks im going to replace my temp sensor and hopefully it will resolve the problem.
straut: I recently changed my maf so I dnt think it has to do with that but ill check and clean it while im at it thanks for your responses.


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## straut (Aug 31, 2011)

I think as Hoggy says it will probably be the temp sender if your temp is running ok @90 as this put the engine light on mine (error in mapped cooling system) or something like that
steve


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## juman20 (Jan 14, 2012)

im almost sure its an electrical problem so I will replace the sensor and see how that goes but like I said it only does it every couple days so ill let u guys know if its resolved.


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## juman20 (Jan 14, 2012)

quick question guys I went to the auto parts store and they tried to give me a sensor that wsnt it I also noticed there are two sensors on the upper radiator hose one with two pins and a square one with four which is the temp sensor and what is the other one for?


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## Hoggy (May 8, 2002)

Hi, This should help for location, best to get OEM sensor..

http://www.wak-tt.com/tempsensor/tempsensor.htm

http://www.vwspares.co.uk/product_info. ... ts_id=2544

Hoggy.


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## juman20 (Jan 14, 2012)

Thanks hoggy but neither of those are what i have here is what i got:

This one is right next to the battery on the upper radiator hose:

http://www.streetperformance.com/part/v ... 35405.html

And this one is right underneath the combi valve on that same hose:

http://www.streetperformance.com/part/v ... 33469.html

so idk because both say are the temp sensor should i replace both maybe?


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## Hoggy (May 8, 2002)

Hi, The 2nd link, looks the correct temp sensor. I assume you are in the USA & left hand drives must have it in a different position. There is only 1 coolant temp sensor that supplys the temp indication on dashpod.
There are others on radiator that controls rad fan cut-ins, but not temp indication.
Hoggy.


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## juman20 (Jan 14, 2012)

you are correct im in us and got the left hand drive and ill replace the second one then thanks for the help.


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## OUTTEA (Feb 12, 2011)

wanted to put in some info on the thread.

I had a bad coolant temp sensor. Badly affected my air/fuel on cold starts. I found the new one at Autozone for $8.99 and its the newer green one. Took me about 20 minutes to put in, only because I work slow and organized (anal). I believe it also effected my turbo boost data like what was mentioned. Noticed it was a bit more perky now 

Thanks to the forum I would have spend many $$$$ in the last month! I had a thermostat, battery and this coolant temp sensor go out on in the same short time period. Fortunately the battery was under full warranty and the whole cost was about $80 in my UTH (Under The Hood) ventures for these.


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## juman20 (Jan 14, 2012)

How did you get the new one in? isnt your connector squared just like the one on the link i posted?


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## OUTTEA (Feb 12, 2011)

Mine is just like the one in the link hoggy posted;

http://www.vwspares.co.uk/product_info. ... ts_id=2544


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## OUTTEA (Feb 12, 2011)

Juman,

Mine is just like the one hoggy posted earlier


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