# cold start issue plus fuel cut off



## mk1_tt (Dec 7, 2008)

Hi, does anyone know what could be the cause of weird cold start issues. If i try to start the car in the morning after its been sitting for the night, it will not start on the first crank, or if it does it will sputter and hesitate for a few seconds then be ok. It only happends somtimes, and when it does it has been sitting for a while. Ive never really paid much attention to this but it seems to be getting worse as time goes by. I also noticed that my car will hit fuel cut off at 7100 in 1, 2, 3 and in 4 will hit cut off at 6400. Is this normal?
I have a 2001 audi tt 180quattro
37k miles
neuspeed intake
42dd downpipe
forge turbo inlet + 007
unitronic stage 2
Im starting the think that i may have a fuel pump or filter issue. 
what do you guys think. 
So far i have changed the plugs, cleaned the throttle body and repositioned it. The dealer also changed the colant temp sensor awhile back to the green top.


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## EuroStyle (Jun 24, 2000)

We've had the cold start thing......it would barely start first crank, or not at all after sitting all nite. This was even in the Summer. It has gotten almost fine once I swapped in the green top coolant sensor, and we let the car sit 5 or 8 secs with the key on before we crank....
Sean


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## Volc0mTT (Jan 4, 2008)

*Re: (EuroStyle)*

change ur 4 pin collant temp sensor it will fix the problem!


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## mk1_tt (Dec 7, 2008)

about a year ago the dealer put in a new collant temp sensor, the green top one. is that what your reffering to?


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## Volc0mTT (Jan 4, 2008)

*Re: (mk1_tt)*

yeah.... its a 20dollar part.... ive replaced mine 2 time the coper or whatever metal seems to blow out on the bottom ill send u a pic whats ur Email


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## mk1_tt (Dec 7, 2008)

ok, ill buy a new one tmr and see if it helps. 
what about the fuel cut off issue, is it related?


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## mk1_tt (Dec 7, 2008)

ok that was a waste of money, I put in a new colant temp sensor in and i still have the same problem. 
First crank in the moring and the car strugles to idle then dies. second start is perfect. Only does this after its been sitting over night.


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*

Im in the same boat as you. Mine will shudder and die on the first start and then I can restart it and it's like nothing happened. Have you had yours scanned? I had mine scanned with vag-com and found no codes.


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## mk1_tt (Dec 7, 2008)

No codes either. Does yours do this all the time or just in the morning?


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*

yup it only does it in the morning or when it has sat for quite a few hours Ie. more than 6hrs. It drives fine no loss in performance. I have a splitter and mine is constantly open at idle. So I am suspecting it is n249 related. All the items it could be are so damn expensive and I'm not going to buy multiple parts in excess of 100 dollars to try to solve it.


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## ecko2702 (Sep 12, 2008)

*Re: (ecko2702)*

Mine usually dies though instead of shuddering. Does yours ever die?


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## mk1_tt (Dec 7, 2008)

yes, it cant idle so it sputters then dies.


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*

Hmm sounds like you have the same problem as I do. I am getting it scanned later and will let you know if I find anything. I think I am going to replace the n249 as well. Hopefully that fixes it.


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## Neb (Jan 25, 2005)

*Re: (ecko2702)*

I'm having this problem as well, curious to find out what it is


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## mk1_tt (Dec 7, 2008)

I will replace the fuel filter tonight and see if that helps, its only $20 and cant hurt to have a new one in there. I hope its not the fuel pump.


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*

I had mine tested and it wasn't my fuel pump as I was told the same thing. I cycled the key on and off a few times and cranked the car once then cycled the key to pressurize the system and it still died.


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## mk1_tt (Dec 7, 2008)

I just changed the fuel filter. It took less than 15 mins. I don't know why Audi says they would last the life of the car because I'm at 37k and it was black and full of stuff. 
I hope this helps my problem.


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*

Did that fix it I replaced my 249 and my check valve for it and mine still dies.


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## IndyTTom (Oct 23, 2007)

*Re: (ecko2702)*

The starting issue is more than likely from your secondary air injection pump failing. It assists in starting the car when the engine is cold.
Those pumps are prone to failure.


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## ecko2702 (Sep 12, 2008)

*Re: (IndyTTom)*

Would that cause it to die then when you restart it it's like nothing happened? Would the air pump also through a code?


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## IndyTTom (Oct 23, 2007)

*Re: (ecko2702)*

It may not throw a CEL but it should show as a fault code when you do a total VAGCOM diagnostic.


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## IndyTTom (Oct 23, 2007)

*Re: (IndyTTom)*

Principle
Due to overenrichment of the mixture during the cold start phase, there is an increased amount of uncombusted carbon monoxide in the exhaust. Secondary Air Injection (AIR) improves secondary oxidation in the catalytic converter and therefore reduces emissions. The heat produced by secondary oxidation greatly reduces start-up time for the catalytic converter, therefore improving exhaust quality during the cold start phase significantly.
Function
In the cold start phase, the ECM -2- activates the secondary air pump - 12- via the relay for Secondary Air Injection (AIR) pump -1-. Air reaches the combination valve for Secondary Air Injection (AIR) -10-.
The Secondary Air Injection (AIR) valve -3- is activated in parallel, which allows the vacuum to reach the combination valve for Secondary Air Injection (AIR) -10- and the vacuum diaphragm for charge air pressure regulation - 7-. The combination valve for Secondary Air Injection thereby opens the path for secondary air to the exhaust channels of the cylinder head.
…
Could also be your combination Valve. if it is Faulty it will cause the Secondary air injection valve to operate imporperly and eventually fail.


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## IndyTTom (Oct 23, 2007)

*Re: (IndyTTom)*

Another thing you could try is disconnect your MAF sensor and see if it still does it. If not you may have a bad MAF.


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## ecko2702 (Sep 12, 2008)

*Re: (IndyTTom)*

mine runs just fine when it's running my DV (Splitter) is always open and it shouldn't be. So I don't know if a SAI would cause that to happen I have had it scanned on vag-com and it found no faults.


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## Warhawk (Jun 15, 2008)

*Re: (ecko2702)*

weird my car just started doing this exact same thing about 2 weeks ago, a solution would be nice


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## mk1_tt (Dec 7, 2008)

well the fuel pump did not help. Back to the drawing boards


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*


_Quote, originally posted by *mk1_tt* »_well the fuel pump did not help. Back to the drawing boards

Damn I hope that was it. I am starting to think it's the Air pump.


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## mk1_tt (Dec 7, 2008)

It could be the air pump, when it struggles to stay alive, it almost sounds like the pump is opening and closing.


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## M this 1! (May 17, 2000)

*Re: (mk1_tt)*

I'll be installing a new fuel filter as a test for my own car. i'll report back in about a week since it's at GIAC getting more power


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*


_Quote, originally posted by *mk1_tt* »_It could be the air pump, when it struggles to stay alive, it almost sounds like the pump is opening and closing. 

kinda what mine sounds like too. I hope it is cause that will fix the problem but that pump is so damn expensive.


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## M this 1! (May 17, 2000)

*Re: (M this 1!)*

2ndary air mainly cleans up the initial start up, high idle emissions. i can't see how it'd help initial start itself. My shop tech Edgar here is who's pointing towards the fuel filter. MOST of us never change it since it's rated at lifetime


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## mk1_tt (Dec 7, 2008)

*Re: (M this 1!)*

I did change my fuel filter, it did not help


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## M this 1! (May 17, 2000)

*Re: (mk1_tt)*

I did not see that. I thought you just changed your fuel pump.


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## Warhawk (Jun 15, 2008)

*Re: (M this 1!)*

what do those 2ndary air pumps run? i really hope that is not my problem


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## IndyTTom (Oct 23, 2007)

*Re: (Warhawk)*

Before you nickle and dime (Or in the Audi's case hundreds and thousands) Youself to death. I would have the dealer check it and diagnose what is actually wrong with it. You don't have to let them do the work but at least they can find out what is causing this issue.
The airpump installed by the dealer will probably not be cheap. My guess is between 600-1100 bucks.


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## mk1_tt (Dec 7, 2008)

*Re: (Warhawk)*

Ya sorry i meant fuel filter


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## ecko2702 (Sep 12, 2008)

*Re: (mk1_tt)*

Hey I solved my issue I got a can of MAF cleaner cleaned the maf reall good and it runs like a champ now


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## mk1_tt (Dec 7, 2008)

*Re: (ecko2702)*

what did you use to clean it. How did you do it?


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## IndyTTom (Oct 23, 2007)

*Re: (mk1_tt)*

Probably he unscrewed the Sensor from the MAF and pulled it and then spray it gently with MAF cleaner


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## ecko2702 (Sep 12, 2008)

*Re: (IndyTTom)*

yes I just removed it and sprayed it carefully with MAF cleaner and then let it sit for about 15 to let it dry then re-fitted it and it was fine.


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## mk1_tt (Dec 7, 2008)

Cleaning the MAF and changing the fuel filter seems to have fixed my cold start problems. 
Now the only problem i have is the fuel cut off issue.
In 1st and 2nd it will cut of around 7000
in 3rd and 4th I have surging in the upper rpms and will cut off around 6100 rpm
what could cause this?


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## FWDTT (Nov 22, 2007)

*Re: cold start issue plus fuel cut off (mk1_tt)*

Can someone explain why the coolant sensor is involved with a starting issue? I think my buddy has the same problem with with 2.7 A6. Thanks.


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