cjm32

I bought my A6 2.8Q in July with 97,000 miles (now has 107). Here's the problem I am encountering:

When I start the car in the morning it starts up perfectly fine. One turn-over and it is good to go (this morning being the lone exception taking about 2 seconds). When I shut the car off, as long as I start it within about 5 minutes it starts up right away. However, after anywhere from 10 minutes to 4 hours later it will take 6-8 seconds to start. During this time when it starts up the rpm's will idle at 200 for a second, then jump up to 400 for a second, then to 600 for a second before permenately idling around 800. This indicated to me that there was a fuel problem, likely pressure related.

Here are the repairs I have done thus far - mostly time change items (totaling $1,400):

August - Fuel Pump & Fuel Filter
September - Coil Pack (all 6)
November - Timing Belt, Serp Belt, Water Pump & Spark Plugs
December - Battery & Vaccum Hoses
January - Fuel Pressure Regulator (prior to replacing this it could take as long as 15 seconds to start).

There are two other things I have noticed - one is that it doesn't have the punch it used to when driving it. Second, I do have a CEL that came on two weeks ago indicating a faulty Coolant Temp Sensor which I will be replacing shortly.

Any ideas on where to go from here?

4Driver4

Coolant temp sensor is a common failure. Replace.

cjm32

Would that be the cause of the long start? I had planned on installing it Saturday but I was wondering if there could be other things that are contributing to this.

4Driver4

Most likely the sensor. You were lucky to get a code; usually you don't.

cjm32

Excellent. I hope that will solve the starting problem and boost the acceleration. I will replace and let you know.

cjm32

Interestingly enough the code changed today from a P0118 to a P1296. CTS replacement still?

4Driver4

Codes are clues. You have seen two of them. One is temp sensor related, the other could be temp sensor, could be thermostat. Coolant temp sensor is cheap, common failure, easy to replace.

meseager

My 2003 A6Q 2.7T has the same exact starting problem.

#4 misfire came up often, but I have replaced all 6 coils, new battery, fuel pump, air filter, water pump, spark plugs, coolant temp sensor, fuel pressure regulator hose, auxiliary water pump, and the list goes on and on.

The coils were recently replaced, and now it starts fine from a cold start (didnt use to). After everything I have done, that has been the only improvement. It is really annoying. Ive taken it to 4 different shops and 2 different audi dealerships and its still not fixed.

fuel pressure was ok, system control ok, residual pressures ok.

There still seems to be a slight oil leak from the left turbo. When it starts, smoke always comes out of the exhaust and you can smell the burnt fuel or oil. Can smell it also every time I drive it and get out of the car, stinks up my whole garage.

Anyone have any ideas please?

s4master1

check the temp reading at the ecm, cluster and a/c unit
usually you can see the temp at the ecm going below zero when it should be at around 60 to 80 celsius
this causes the ecm to open the injectors longer and wet the plugs causing longer cranking to start the engine
there was a bulletin on this needing replacing the temp sensor, plugs and thermostat back in 2001

s4master1

check the cam plug at the back of the head, when it leakd it drips right on top of the turbo, we always replace them together with the cam adjuster seals, valve cover gaskets and cam seals