Car won't start, no connection with the engine

[Pirrex]

Got this problem when I tried to start my car two days ago. Noticed straight away that i can't hear the fuelpump running, tried starting and it obviously didn't start. Did a direct connection to the lift pump and it started running; the pump is ok.
Tried starting again, but still nothing. checked if the sparkplugs were wet, but they were dry. Now i checked if the electrics worked, but i didn't even get a spark! Tried vag-com to see if i got any fault codes, but it wouldn't connect neither with Engine or Central electrics, but everything else seems to work fine.
I have also checked all the fuses on the side of the dash and all the three i found under the steering wheel, is there one i haven't noticed?
Tried also reattaching the cables to the ECU, but no success.
Ideas what to try next, anyone?

 

[Pirrex]

Nobody? Anybody know any places for "hidden" fuses? There should be one under the hood according to autodata, but cant find it?

 

[Nilz]

It could be your immobiliser, but I cant be sure, just guessing.

What car is it, some more details of that could help in getting a better response.

 

[adamss24]

Nobody? Anybody know any places for "hidden" fuses? There should be one under the hood according to autodata, but cant find it?

Check the power supply relay aka as relay 109 on older cars.

 

[Broken Byzan]

Check the power supply relay aka as relay 109 on older cars.

Where does this reside?

I have a similar problem on our TQS but it only happens when its below 3 degrees oputside.

I have changed the ECM relay mounted under the bonnet

 

[RichA3Turbo]

Where does this reside?

I have a similar problem on our TQS but it only happens when its below 3 degrees oputside.

I have changed the ECM relay mounted under the bonnet

In the A3 (and probably the A4) The relay box is under the steering wheel undertray. Just remove that and its under the headlight control. The fuse panel is in the access panel at the end of the dash on the drivers side (with the door open). Just prize it off with a flat head driver.

Rich

 

[RichA3Turbo]

Fuses and relays are the best thing to check first of all.

Failing this, get a multimeter on the fuel pump connector at the pump and see if there is even any voltage going to it. if there is, then the pump itself is the issue. If not, then its something else. the immobiliser is also a possibility.

 

[RichA3Turbo]

having reread your post, your ECU may be shot if you are not getting spark either and cant vag-com. i'd pull the ECU and check it looks OK, and just be sure the connectors are being held firmly in place.

 

[Keeno]

Top of the battery.

3 fuses inside a black box mounted on nthe battery. Controls all current to the rest of the car and are prone to going pop thanks to corrosion caused by the gas from the battery rechargeing.

 

[Pirrex]

It cant be the immo, as the pump will work if that was the problem, and the car would start if that was the case, and shut of after a second.
The pump is also fine, because it works when i give it power directly, but the ecu will not let any fuel in tho. Will check all the fuses and relays when i get home for weekend, would just like to know all the places where they're hidden.

Afraid is the ECU.

 

[Pirrex]

Btw. which lights should light up on the dash when i turn the power on? Do i remember wrong, or shouldn't one on the left which says EPC light up, because it doesn't now?

 

[Broken Byzan]

On ours when its cold the ECU wont power up, and the EML light wont come on either.The EPC one does iirc.

But as its warmer at the mo, the car continues to work

 

[Pirrex]

That's also weird. I wish s3's wouldn't be so rare up here so i could try somebody elses ECU. Also almost impossible to find one that's for sale too, but i would gladly buy one if somebody had one extra here

 

[Pirrex]

All right, got a "new" ECU from ebay and it's working now!
Used to be remapped, but stock now. To you others who are driving your S3's stock: Get a remap, this is like driving a Punto lol