Fuel pump issues or..?

graham d'arcy

graham d'arcy

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i think my fuel pump is on it's way out. But I'm not sure.

The only symptoms I'm getting are, slightly slow to start up when under half a tank, and when accelerating a bit hard and trying to switch gear and floor it, the car just will not accelerate and it jumps or hesitates.

I changed fuel filter, took off injectors and gave them a proper soak, changed spark plugs, and its runnning fine when I'm driving normally and even when I'm In a gear and am driving normal then put the boot down it's fine but when changing gear and hard accelerating it just will not keep going.

I originally thought it was the clutch slipping but it's not, the clutch is actually fine.

Anyone had any similar experience or what happened when anyone else's fuel pumps failed?

No error codes either.
 
Needs logging in VCDS... need to log block 031 AFR request vs actual, 001 lambda control value and 002 for mean injection on time

If AFR actual can't meet requested AFR then look at lambda control value to see if its having to add a lot of fuel and injection on time to see if its maxing out (heading towards 20ms)

Alternatively a fuel pressure gauge in the rail supply line...

<tuffty/>
 
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Cool, thanks, I'm gonna hook it up over the weekend, will post pics here if I cant make heads or tails of it and hopefully someone here will be able to dumb it down for me.
 
Right. Changed the fuel pump, still happening. Changed the n75. Still happening.

The problem is literally only as I change gear in high revs that this happens, the whole way up the rev range it's fine.

No access to vagcom. So I'm stumped.

Crankshaft position sensor?
 
audi upgrades
Where are you located. I'm sure someone nearby could scan it for you for some beer tokens.
If your near to Surrey/Hants I'd be more than happy to help.

As slammedorion says guessing IS expensive
 
Dublin Ireland. My cousin has one. Just hard to get a hold of him or my mate who works for Audi is about a two hour drive. Just will take time to get them. Would be ideal
If someone had the same
Issue and just told me to replace something and it works. But sure that's not how the world works :D
 
When I had misfire issues more recently - I disconnected the N75 and kept my foot flat when it started misfiring until I got the hard misfire EML light flashing and then got a code for which cylinder to change. before that it just felt like it was missing / hesitating when I pushed it - I too changed the fuel pump to no avail. (I only disconnected the N75 so I wouldn't be going crazy)

The failures for misfire I have had were
coil gone (due to broken ceramic on spark plug)
spark plugs broken down (due to overheating / lean?) - only when under load.
coil rising due to vibration.
 
Changed spark plugs last week to Bkr7eix

Coils were done on recall about 5 years ago I think?

So yours actually threw up a light when you kept the foot down?

I do panic that the engine will blow if I don't lift off the accelerator when it's hesitating
 
that's why I unplugged the N75 just to take the load off - I spent a few weeks always on the same section of road if I floored it over about 5K it felt empty and hesitant and would pick up again if I rolled on a bit - that's why I changed the fuel filter and fuel pump. but as soon as I got a flashing light it showed up cylinder one on Android Torque (which has been a problem cylinder in my car - slight damage to the head from broken spark plug ceramic, the spark plug failing only under heat / reckon running too lean on stage 1 map after multiple upgrades - rising coil pack blamed on vibrations - post low oil (engine wear))
 
So what did you do, just replace the coil and spark plug?

My car is remapped too, the next direction I was taking was the crank shaft position sensor, then coils replacing, then if those failed have the remap redone possibly, assumed it could have just been a botch remap whoever got it done?

Is there a way of tracking the misfire or knowing its the sparks or coils without a light coming on?
 
maybe VCDS is able to show misfire without a flashing light - you need to have the fault code for the cylinder rather than multiple random misfire which is not specific - for at least swapping coils to another cylinder to see if the fault moves.
I had bought copper spark plugs and re-gapped according to the stage 1 guide and I think my car was too hot and one broke down during high engine load after warmed up. I replaced my 1000 mile plugs with the iridium ones you have and they have been okay since.

it might not even be a misfire :)

do you have Android Torque?
 
Stuart B said:
maybe VCDS is able to show misfire without a flashing light - you need to have the fault code for the cylinder rather than multiple random misfire which is not specific - for at least swapping coils to another cylinder to see if the fault moves.
I had bought copper spark plugs and re-gapped according to the stage 1 guide and I think my car was too hot and one broke down during high engine load after warmed up. I replaced my 1000 mile plugs with the iridium ones you have and they have been okay since.

it might not even be a misfire :)

do you have Android Torque?
Click to expand...


Ok. So update. I kept my foot flat to the floor today and the engine management light finally came on for the first time. This is good news. Hoping it's just a coil gone. At least it's finally going to tell me what the problem is.

Going to get it hooked up next weekend and see what the problem is.

Did you have your vag com hooked up when the error came up, or does the car log the code once eml comes on? Or will it need to be plugged in while I make the eml come on?
 
audi upgrades
So I have a few faults ....
 

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I'm just a total beginner, but the error is a "short on the sensor", so maybe the reading you are seeing of 1100 c is the sensor max because it's knackered?
 
Had the same problem... New EGT is not cheap but worth changing. Will fix MPG and car performance. Changing is quite tricky and after changing it relocate the plastic modulle which is bolted under the inlet manifold because heat from the mani affects it.
 
Stuart B said:
What do you class as brutal MPG? Under 20 as the average is usually 25 anyway isn't it?
Click to expand...

got 30 on a long run 200 miles of motor way, VERY easy on throttle, maybe not even going over 70MPH

And now from normal driving, always in the slow lane on dual carriage way and never speeding, its dropped to 23.9 and falling like a lead balloon

EmilS3 said:
Had the same problem... New EGT is not cheap but worth changing. Will fix MPG and car performance. Changing is quite tricky and after changing it relocate the plastic modulle which is bolted under the inlet manifold because heat from the mani affects it.
Click to expand...

What were your symptoms before the issue? same as mine? did you have the 1100 degrees Celsius temperature too?


badger5 said:
fault - 1100'reading + overfueling
Click to expand...

So its definitely just the sensor needs replacing and nothing else?
 
I get bout about 28 mpg and most of my driving is town driving. I think that is good but from these cars i dont expect brilliant mpg if i did i wouldn't have bought a s3.
 
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You don't get a hot hatch if your concerned about mpg. You don't even want to know what I get from my r32
 
If I'm in chill mode I'd get around 21-22
But if I get a bit giddy around 16-18 I try to ignore other wise I get upset ha

The money I spend on fuel I could have my s3 back on road
 
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Yeah I didnt buy it for MPG obviously, but my mates and my cousins are about 6 MPG better, and they drive harder than I do. So my problem is its worse than it should be.
 
graham d'arcy said:
So its definitely just the sensor needs replacing and nothing else?
Click to expand...

come on - how can anyone confirm that will be the last and final thing - you know these cars.

but the ECU will think it is running too hot and throw in more fuel - so replacing that sensor hopefully will resolve this fuel over use.

no photos (photobucket) - but sounds expensive and a little fiddly

http://www.audi-sport.net/xf/threads/egt-sensor-location-on-03-s3.109511/


I can get 30 on a run 100 miles, and 25 on normal driving to work (17 miles including traffic etc)

the crap mazda 3 2.0 - doesn't even get above 25mpg - that must be a fault.
 
Stuart B said:
come on - how can anyone confirm that will be the last and final thing - you know these cars.

but the ECU will think it is running too hot and throw in more fuel - so replacing that sensor hopefully will resolve this fuel over use.

no photos (photobucket) - but sounds expensive and a little fiddly

http://www.audi-sport.net/xf/threads/egt-sensor-location-on-03-s3.109511/


I can get 30 on a run 100 miles, and 25 on normal driving to work (17 miles including traffic etc)

the **** mazda 3 2.0 - doesn't even get above 25mpg - that must be a fault.
Click to expand...



I just want this hesitation gone, i dont even care about the fuel i just want to be able to drive my car :( getting one now next friday so hopefully it solves the problem so I can order my badger 5 TIP and start enjoying the damn thing
 
yeah I spent a year trying to fix basic things before being able to try anything fun - but mine's on its last legs now anyway :D
 
Stuart B said:
yeah I spent a year trying to fix basic things before being able to try anything fun - but mine's on its last legs now anyway :D
Click to expand...


I read through that thread above, and nothing conclusive of anyone having these problems and it fixing the sensor and it solving the exact problem. disaster.

and I know as soon as this is fixed something else will happen hahah
 
graham d'arcy said:
got 30 on a long run 200 miles of motor way, VERY easy on throttle, maybe not even going over 70MPH

And now from normal driving, always in the slow lane on dual carriage way and never speeding, its dropped to 23.9 and falling like a lead balloon



What were your symptoms before the issue? same as mine? did you have the 1100 degrees Celsius temperature too?




So its definitely just the sensor needs replacing and nothing else?
Click to expand...

With your 3 cylinder misfires did you change the coils or check the plugs? As if it was over-fuelling won't they all be fouled?
 
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