Hi Guys,

My first post, just registered.
I bought recently an older audi a4 2004 (B6 I believe).
It's a 2.5 diesel.

I bought it as a 2nd car for my wife to take kids to school and shopping.
Car is in quite good shape over all, all works well except for the cold start issue I'm having.

When car is completely cold, and especially now as winter is around with around 0C outside, the car takes about 7-10 seconds to start of continuously having the ignition turn. When it starts it runs absolutely fine. You can then drive it right away for hours without any problems at all, idles fine as well once it starts.

If you have it running for at least the 5km run to get kids to school so it warms up just a little bit, it starts then without any problem within about 2 seconds of turning the ignition. The problem comes back only when the car has been sitting for a long period of time, for example, overnight, and next morning.

I've read multiple threads about similar issues and feel I've tried many things listed there, but could not narrow it down yet, here is what I've done:

* I've replaced all glow plugs with new ones
* I've replaced the coolant temperature sensor with a new one
(I've also unplugged the temp sensor and tried starting with it unplugged as it said somewhere that this will make the car thing it's -40C outside and give full power to glow plugs, but that didn't help)
* I've replaced fuel pump
* I've checked all fuses in the fuse box inside the car

I'm not a mechanic, but feel like the problem sounds like is with the glow plugs not working properly... unless you have any other ideas what else to check?? Is there a way to check if there is electricity flowing to glow plugs, maybe I've missed a fuse somewhere else outside the fuse box inside the car?

Anything else it could be?

Does not feel like the issue is with anything big as the car runs absolutely fine when just a little warm, something is just not helping it to start when it's cold..

Any suggestions would be much appreciated.

 

Did you resolve this? Had similar problems myself. Read it could be a leak from the fuel injector?