paulgg

I have an Audi 1.9 TDI 2003
I'm having a problem with it starting and dies immediately (3-5 sec) then it will not start, the engine does turn but does not start, seems like no fuel
This occurs approximately once every three months. I need to then fiddle with the electronics at the computer box under the hood, it will eventually start,
any help would be much appreciated

lyleswk

Not familiar with the 1.9 TDI at all, but when you say "computer" do you mean the ECU in the cowl area? if so is there water intrusion that is affecting relays or wiring?

paulgg

In the past there was water in the ECU cowl area where the car died while driving with some wires burning out. This was repaired and had no problems for a while. Every now and then the car starts and immediately dies and then only turns, after fiddling in the ECU area with relays and wiring it will start and will be fine for a few months until the problem reoccurs. The relays do appear to work and i am unable to narrow down where the exact issue is.

lyleswk

Unless someone has a better idea, it seems that you have an intermittent problem with the ECU or ECU wiring which will be difficult to find.

paulgg

Hi again, firstly thanks for your replies lyleswk. I managed to eventually get the car started by continues cranking, does this mean the fuel relay or pump is faulty? Does anyone know which relay controls the fuel in the ECU cowl.
Audi 1.9TDI 2003

gsjohal

Hi.
A common cause of non starts, is the engine speed sender. It tells the ecu that the crank is turning, to allow fuel to be supplied. When they fail (and they can fail intermittently too), this prevents the fuel pump from operating as the ecu doesn't get the signal that the engine is turning over.
Ideally you should have the faults read with a scanner to confirm this.

paulgg

Hi gsjohal, thank you for your reply! The vehicle is now running perfectly until this problem occurs again normally at home (thank goodness) using a scanner now would not reveal the problem, it is very disturbing as I'm not sure when it will happen again, away from home e.t.c
Wish I could pin point this problem.

Prospeeder

A bad 109 Relay will do this sort of thing when they are on the brink of failure. They cost like 15$ and fairly easy to replace. Do a little search on it, they are the main power supply relay for the engine management. I obviously am not in Europe but I would imagine this relay is on most TDI powered VAG cars from this Era.

lyleswk

It that relay installed on the ECU?