Hi, I find that my car (99 A6 2.8) is hard to start after sitting for a while. I will have to hold the key for about 5 secs every morning to get the engine started every morning; if I drive during the day ususally it takes 1sec to start it. I do find it seems to be easier to get it started in the Winter.

Any input is appreciated!

 

Just to make sure, you do wait for the car to stop beeping and warning lights to go off before you turn the key first time right?
Can't positively say it's bad fuel pump because it's in the tank not under the hood and car is fuel injected...
You should do regular maintence, replace plugs filters etc. Also, I would check fuel pressure if other things do not help.

 

Yes I do wait for all lights. I just changed the plugs and the filter. But if it is the fuel pump, shouldn't it be like that all the time?

 

anyone has more ideas? I went through the forum and see people talk about coolent temp sensor and the o2 sensor, and even throttle body alignement. Would they relate to my problem? thanks.

 

A bad coolant temp sensor definately, bad forward bank O2 sensors can cause starting issues as well.
The throttle body alignment probably won't cause a starting issue as much as it would bucking or stumbling issue. Do you have any fault codes?

 

Thanks Auditech79 for your kind replay. Strange enough is that I don't have any fault codes in my ECU. I suppose that's where I should be looking at.

Generally my engine is easy to start when it is still warm.

can you also explain more about the bucking or stumbling issue? I feel my car's vibration is a little excessive when I stop for lights (e.g., foot on break paddle, gear is in D). I am not sure if it is related to the throttle body alignment.

 

If either sensor goes bad, should I have any error code? Do you have any DIY article on the sensor replacement? (99 A6 2.8)

 

I would start with the coolant temp sensor, they don't always throw a fault when they go bad. Its easy enough to replace, its directly behind the engine on the passenger's side facing upwards to the hood of the car, you just pull the plastic clip out and pull up on the sensor. Install a new sensor and o-ring and see what it does. 75% chance thats what the problem is.

 

Today I started replacing the ECT sensor. But I noticed that the new green sensor is a lot longer than the original blue sensor where it is interfacing to the wire connector. Actually I don't think the green one can be plugged into the wire connector. Did I purchase the wrong one? But this is what the dealer says the right replacement.

BTW, I find the ECT is very difficult to be pulled out. I have not been able to accomplish this part yet.

 

Replaced the ECT, the engine still took a long time to start today. Any more idea? Thanks.