RS246.com Forum :: The World's #1 Audi R, S and RS Enthusiast Community

So this the second time in a few weeks this has happened... Tried to start the car, and it turns over but won't fire. Happened a few weeks ago too, but then was fine a couple of hours later. I didn't want to try for too long and flood the engine, plus I eventually got a low oil pressure light so I've left it alone for now.

I've lent my vag-com to someone, going round to pick it up in a bit, any ideas in the meantime?

If it was a clutch switch, I wouldn't even get the starter turning over I assume? So relays or starter?

Any help much appreciated

Common issue on the 4.2 S4 and RS4 sadly. Will be one of three things:

Start button on dash
Starter motor relay
Starter motor

If its intermittent, I'd imagine starter motor relay, previous posters have found they don't like cold / condensation, hence the car starts when they try again later on

Starter motor relay is on the starter motor. So you might want to do both at once given its horrible location.....

Yes, relays were my issue. Threw lots of erroneous fault codes though.

Ok thanks guys, much appreciated. So, relays plural?

One on the starter, and what other ones should I be interested in? Also, do you know the locations?

Have a read through this for the relays under the ECU, it will require removing the drivers wiper arm to get the ECU out of the way. These realys do not always present the same faults due to their control over the main ECU's.

viewtopic.php?f=35&t=110830&hilit=Relay&start=15

Surely the car won't turn over if it is the usual relay, starter motor or button issues? I thought all of these failures would stop the starter turning.
And can you flood a modern engine?

I've been having the same problem but only when the engine is hot. Turns over fine but struggles to start, thought something to do with fuel and hot manifold ??

When you open the driver door, does the fuel pump make a whirring noise to 'prime'? Just thinking about a fuel pump issue?

Low oil pressure unlikely to other than a red herring as the sensor is expecting more pressure and assumes the car is running.

Thanks for all the responses so far guys.

Working with a new theory - my car doesn't like Wednesday evenings. Either that or it doesn't like my buddy Tom I take to basketball training. Both times I've had this issue was on a Wednesday before training!

I went to start it this morning and get the various dashboard lights on camera...

https://vimeo.com/162796372

Sam/Ian/others that have had this issue, with reference to what Mike said, would your cars turn over?

Will be giving it a scan this evening after work, but I'm expecting an unhelpful mess of codes.

I had starting issues last year and the fix was a new starter motor after trying relays. The engine would not turn over though.. You pressed the starter button, you could hear the relay clicking but engine wouldn't turn, then wait 2 mins press again and the car would start. This was intermittent for a couple of months before I pulled the trigger on a starter.

FaisalJ wrote:
Sam/Ian/others that have had this issue, with reference to what Mike said, would your cars turn over?

My symptoms were that the starter motor would spin like usual, until the system times out (wasn't long) and the engine just wouldn't fire up. Not even a splutter.

Surrey Sam wrote:

FaisalJ wrote:
Sam/Ian/others that have had this issue, with reference to what Mike said, would your cars turn over?

My symptoms were that the starter motor would spin like usual, until the system times out (wasn't long) and the engine just wouldn't fire up. Not even a splutter.

Ah, that sounds like my issue.

I'll order a couple of relays and start from there.

I've been told by Audi that the part number has changed from

8E0 951 253
to
4H0 951 253

Just in case anyone else comes across this thread and needs to get hold of the relays too.

Sounds about right, I got mine through TPS and was told about a part number update.

Worth getting some penetrating fluid onto the driver side wiper arm spindle before you start on the job.

We have seen a few cam position sensor faults causing your symptoms but usually there will be a fault stored for it. The cars usually spin over fine but make zero attempt to fire.

If it's turning over then it's unlikely to be a starter related issue.