my S4...1st impressions!

[fletchie55]

finally got to take my new car for a spin and I was slightly disappointed.

interior quality and comfort is great
sound system is definately top class
handling is fine, especially for an estate and I didnt push it hard anyway.

BUT.. I was realy disappointed with the performance, my old fiat coupe 20V turbo would absolutely destroy the S4. It was modified, and probably had around 260BHP but considerably less torque.

Im convinced theres something wrong with it, it almost feels like a deisel car, running out of 'puff' after 5k revs! 70mph to 100 (of course this was on my own private road) was pretty reasonable, but acceleration in 1st, 2nd and 3rd seemed a bit weak, and by 5k revs it just seemed to make a bit more noise and not go any faster! The car certainly has a lot more torque than my old car as theres no need to change from 5th at 30mph.

I have got a cheap diagnostic cable to check fault codes, so I guess thats my first step! watch this space cos im convinced im going to need some help interpreting the results if I can even figure out how to use it!

[GrahamS4]

Hi,

Only had my S4 for a few months.

You could be in 6th at 30mph, 4 up, and still not change down!

You have probably hit peak power, certainly peak torque by 5Krpm. So although perhpas not useful, my car when stock certainly reved through to 6Krpm without me feeling like I was strangling it for the sake of it - it should certainly feel free reving IMO. Although I now only ever catch the rev limiter occassionally since my remap which has made the car "loosen up" in the higher revs.

Perhaps the power delivery is just different to your Fiat? I expect the Fiat was quite high reving too, a light car and only 2wd - if the power of the 2 really is similar, you now have a heavier car (check the weight I mean HEAVY!) and you have more losses through the 4wd.

If your reference to feeling like a diesel was an extreme exageration, I would perhaps almost agree - the power does come in big low down and I don't think driving these cars with the rev counter at 4o'clock is the way to get peak performance.

Get it checked and I hope it's OK or a simple fix. Enjoy.

[fletchie55]

Im kind of hoping there is something wrong and that its realy cheap to fix! there are no warning lights or anything, and there dont seem to be any strange noises.

One thing I noticed is that the temperature stays at 90 nearly all the time, its never gone higher than this, but only dropped slightly lower on a long motorway cruise, is this normal?

[GrahamS4]

I would say water temp yes - oil you will see go a bit higher depending on situation.

How much have you read up?

I am no expert but there are a few known weakspots to have checked - diverter valves, and in general boost leaks, and as with any car with a Bosch MAS these days - there's a chance it needs replacing.

I think anything else nasty will flag up with a fault code.

[tartan_rob]

You need to get it into a specialist for a health check. Even Audi would fail to find the most basic things. There is mountain of little things that do go wrong over time and as they don't throw fault codes, no-one checks them. These little things can mount upto a lot. FYI...it has been a looooong time since I drove a std car but when std, my car was quicker than my neighbours 280bhp M3. I bought my car with stuffed exhaust Gas temp sensors (no warning light). I changed them and the car stepped up a notch in performance. I'm sure the garage would have charged me more had he known the performance potential.

Get it checked and find out whats wrong. Perhaps someone local can run down with VAG-Com or can give you a run in a good one?

[fletchie55]

will my cheapo ebay diagnostic cable be any use in helping me diagnose any of the above known issues? (MAS, diverter valves, boost leaks etc)

il run the car up to MRC as soon as possible, but its quite a treck from sunny devon!

My trip computer doesnt give a stable MPG reading either, it jumps all over the place, is this how it should work?

[fletchie55]

ive done some reading up, but the more I do the more scarey it becomes and starts me thinking there might be more things wrong! more back ground info on the car: it has 94k on the clock, full audi history serviced ever 10k its 2000 face lift model

[Nige_RS4]

My trip computer doesnt give a stable MPG reading either, it jumps all over the place, is this how it should work?

Are you sure you're not looking the instantaneous MPG setting?

Take a look in the DTC/VAG-COM section of the forum for your nearest forum member with VAG-COM.

HTH

[maxxximus]

Youve just bought the car ? - how did it compare to others you test drove.

Gotta ask but if your not happy with performance of your S4 why did you buy it - if it doesnt fly then theres clearly something wrong.

[Dr-Al]

finally got to take my new car for a spin and I was slightly disappointed.

interior quality and comfort is great
sound system is definately top class
handling is fine, especially for an estate and I didnt push it hard anyway.

BUT.. I was realy disappointed with the performance, my old fiat coupe 20V turbo would absolutely destroy the S4. It was modified, and probably had around 260BHP but considerably less torque.

Take it out for a drive whilst logging group 3 on the VAG-COM (with a laptop). Whilst the logging is going on, do a couple of 'foot flat down' sessions in second and third gear. When doing this, take it right to the rev limiter. When yo get back home, take a look at the peak reading for the MAF (g/s). If the highest reading is less than ~190, you are almost certainly looking at a failing MAF sensor.

This will not give any error codes until it is well on its way out, but it will cause the engine to run lean because the ECU is being told that there is less air going into the engine than there actually is. Once the peak reading drops to ~180 g/s (my guess) you will start to see DTCs that state that the engine is running lean.

This happened to me and changing the MAF sensor turned it into a different car!

[fletchie55]

I got the S4 as its about the only fast and yet still practical car I could think of! I considered a V70 R volvo, but these are even more rare! I wanted an estate so I can throw all my surfing gear in and put the boards on the roof. it is possible that having driven my coupe turbo more recently I just need to get used to the different power delivery. The coupe feels obscenely fast between 2.5 and 5k and its maybe this 'punch' that im missing and making me think the Audi is slow.

[Nige_RS4]

The 20v turbo coupe is also about 300kgs lighter than the S4, so it should feel significantly faster. You will need to get the S4 remapped to be on a par with a 260bhp 20v coupe ... and some!

Still think you may have a problem with yours though.

[ZeroK66]

Fletchie... give me a PM - I live in Exeter and would gladly take you for a spin in my Stage II+ S4 - I am confident this is performing 100%

When I bought the car - FROM AN AUDI DEALER - who gave it a full clean bill of health - the first thing I did was book it in with MRC. 2 days of ownership and I was with MRC. They found the MAF was underreadyin (So underfueling) giving the car quite a jittery power delivery, one of my diverter valves were not working - giving aweful lag.

I had these replaced and off I went. The car pulled like a train smooth & much of my lag in gear changes was gone.

A week later I had my F-Hose split and I then got a boost leak. Back to MRC and they sorted it for me. Now the car is running very well and performs awesome.

It is safe to say you are likely to have an under-reading MAF and a possible boost leak along with dodgy diverter valves.

Give me a PM and we can get together and compare cars

[dummi]

i think maybe you are noticing the difference in weight.. if you were to do a basic remap or generic chip im sure you'd be more than happy.. though it could be something as silly as a split hose or or bad sensor making the car perform so poorly

[Dippy]

Im convinced theres something wrong with it, it almost feels like a deisel car, running out of 'puff' after 5k revs! 70mph to 100 (of course this was on my own private road) was pretty reasonable, but acceleration in 1st, 2nd and 3rd seemed a bit weak, and by 5k revs it just seemed to make a bit more noise and not go any faster!

Based on this I have no doubt that there is an issue with the engine. As others have noted, there are a lot of things that can affect performance and they do not always generate DTCs. A bad MAF is a perfect example.

It might seem a PITA to you, but you MUST go to a specialist for a healthcheck. There are several about - MRC and AmD in the Midlands, QST and the other one I can't remember the name of but they're near the M4 around about Swindon. There may be others nearer you.

I don't want to worry you, but underperformance may be the least of your worries. In extreme cases involving air leaks or severe underfuelling, you can cause damage to the turbos in the medium term.