S3 won't start :(

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slowcoach3

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I've searched lots but can't seem to find any definitive answers. My S3 won't start, I've sorted out the power issues I was having with various sensors but still won't fire.
I have spark- checked the against the cam cover
There fuel - plugs are wet and stink of petrol
Air - yup plenty of that!
Starter is cranking over nicely , I've also tried with the battery and jump leads on to my other car in case the brand new battery wasn't providing enough power.
There's no current fault codes, any codes there were haven't come back. I'm now stumped, any suggestions or ideas greatly appreciated, Cheers
 
it might seem desperate and 1970 / 1980 style but have you tried towing it in gear to start?

surely the most important bit to establish is whether the engine can actually run, when I changed my fuel filter it took about 2 or 3 minutes to get it to start.
 
If I'm honest that would be something I'd be happy to try, only problem I have is that it's parked in a spot it's almost impossible to town to tow it out of!
I've put 15l of v power in on top of the 5l ish of old fuel in there to try and make sure it gets some fresh fuel. It's coughed a few times like it really wants to but hasn't quite caught yet!
 
Try this !
Have a go at starting it then when it won't , unplug the injectors and leave them unplugged while you try again !
I had exactly this issue and it turned out to be the coolant temp sensor of all things .
Was telling the engine it was massively cold so was hosing the fuel in !!!
Worth a try ?
 
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Mate anything is worth a try! How the hell you came round to trying that is beyond me, not something I ever would have thought of! Cheers
 
It was worth a shot but didn't work! Just sticking in another set of plugs to see if I get any joy then if that fails I'll throw a new crank sensor at it just in case. I hate playing the randomly change parts game but I think that might be what it needs
 
my mates water pump had seized and the tension on the aux belt ment the engine couldn't start
 
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Cheers dude, I'll check that tomorrow! If you have spark and fuel there has to be something simple preventing it starting, just need one find that simple thing
 
AA home start found his problem after he spent a few days trying to start going through the normal stuff. It is at least a free check. His problem only came to light after not running his car for a few weeks.

Obviously different cars but you are getting desperate.
 
Have you tried it with the maf unplugged? It could be a maf problem, air intake temperature sensor could be dirty, give it a blast with brake or carb cleaner.
 
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Cheers gent's, off to pick up a new CTS in the morning so I'll check those things first before I go!
 
Update:
I have fuel at the rail but zero fuel coming through the injectors when cranking. With ignition on last point the injectors get 3.5v - this stays the same when cranking!
Any ideas as I'm lost now?!
 
Last edited:
Is the FPR involved at this point? Or has fuel already gone through? Could it be a vac leak.
 
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Cheers dude, I swapped out the whole fuel rail and injectors for a spare set up i have, just on the random off chance that all 4 were blocked. Made no difference.
The injectors themselves aren't actually getting enough power to fire, I now need to establish what is preventing them getting the full 12v. No idea where to go with that though
 
They do click usually don't they? Could it be a relay or fuel issue? Or a wiring fault?
 
Tried 3 relays and same result, fuses ( apart from injector fuse ) show the correct voltage when cranking so the relays are OK. I think.
I've already tried another ecu with the same result.
Next and only step I can think of is to replace the whole injector to ecu loom to see if there's a short/break /problem:(
 
this is far too technical for me - the process of elimination can become pretty expensive though.
 
Replaced entire injector loom back to the ecu with a spare I had just in case. That didn't help sadly. New crank sensor fitted as I had a spare and still no difference. Injectors are still not firing as they don't have enough voltage. The only way I can get 12v to the injectors is to temporarily put fusebox terminal 87f on to the terminal 30. Car still won't start though.
Still no relevant codes either.
Just to prove it will actually start I went very old school and sprayed a timbleful of fuel into the intake manifold and it started so definitely has spark, air and compression just no fuel through the damn injectors! Getting marginally annoyed now
 
Just because no one likes a thread with no resolution...
I got ****** off and went to change the fuel pump today , pulled it out and found that the hose that connects the main tank to the pump ( inside the tank ) had been disconnected. Personally I've never seen a pressurised fuel fitting come undone of its own accord whilst parked up. Guess it must have happened parked at a 'mates' garage. Now starts first time every time. :)
And then cuts out after 2 seconds like the immobiliser kicks in but it's progress!!!!
 
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I cannot help but laugh at your unfortunate signature, not at you - but with you :)

"350 lbft sleeper"

I'm sure you will get to the bottom of it, I have an ECU fitted in mine with "Immo Off" - so you can change the ECU settings to ignore the immobiliser .

That's crazy you found a disconnected Fault Pump Pipe? must have been checked and then put back in a strange way.

you are 100% sure your fuel pump pipes are the right way around aren't you? there has been a previous Thread where the car didn't start with the fuel pipes IN in the OUT and the OUT in the IN !
 
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Weird I can't see my own signature anymore! Cars changed a little since it was in full modded mode.
Nah inlet and return are correct at the pump and rail, it was inside the tank itself that a pipe was disconnected. I'll wack vcds on it in the morning and see if there's any immob codes, I have a spare slightly detuned ecu I intend to run anyway so I'll just get the immobiliser edited on that if that's the problem. To be honest right now I'm just super stoked it's actually starting, game on again :)
 
slowcoach3 said:
Weird I can't see my own signature anymore! Cars changed a little since it was in full modded mode.
Nah inlet and return are correct at the pump and rail, it was inside the tank itself that a pipe was disconnected. I'll wack vcds on it in the morning and see if there's any immob codes, I have a spare slightly detuned ecu I intend to run anyway so I'll just get the immobiliser edited on that if that's the problem. To be honest right now I'm just super stoked it's actually starting, game on again
Click to expand...
Did you find the resolved cuz I have a similar issue
 
audi upgrades
Check the rpm when turning over, the crank sensors seem to break often on these, especially if any other work is being down, they just randomly seem to break when the battery is reconnected. Maybe something to do with whether the motor is in a certain place...

It should register about 200rpm whilst turning over
 
Stuart B said:
Check the rpm when turning over, the crank sensors seem to break often on these, especially if any other work is being down, they just randomly seem to break when the battery is reconnected. Maybe something to do with whether the motor is in a certain place...

It should register about 200rpm whilst turning over
Click to expand...
The car starts when I spray brake cleaner in the intake and then dies again, I'm running ECUmaster and all the trigger sensors are okei that i can check also I've checked the injectors and the fuel regulator so I think the pump is dying on me
 
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