S3 hesitation on acceleration

warren_S5

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Hi all

This is my first post here, so firstly hello everyone!:icon_thumright:

I'm scratching my head this week as my 07 Audi S3 has come back after a whole week in the dealers. The car had a hesitation when accelerating in 3rd/4th/5th and 6th gear over 5,500rpm.

I checked the car and visually all looked in order.

I had a Forge diverter valve and Carbonia air intake / filter so my dealer basically washed their hands and didn't want to know. Paperwork read: "Car modified, therefore no further investigation undertaken" (!)

I have carried out my own checks and found the DV was stuck (Took me 1 hour to find the issue, not 1 week). However having changed back to an OE DV I have found this has not resolved the issue.

I have subsequently removed the negative battery terminal to hopefully allow the ECU to re-adapt. I will then try again tomorrow.

Any ideas or words of wisdom??

I haven't been able to log for error codes yet but aim to get this done tomorrow.

Just one other thing to note, I had to have a front damper changed as it was defective (at 8400 miles). Not a major issue, but something to keep your eye out for.

Cheers

Warren
 
Hmmm, the infamous coil packs.

I'd love it to be coilpacks, as its fixable and warranty covered.

I was really concerned that the DV had caused an issue further back down the chain of events. The internal piston was locked absolutely solid. I've returned it to manufacturer so they can check it out.

I'm at Revo on Friday so they will be doing some logging on it.
 
Welcome to the forum mate :) Good to see you took my advice and joined up!

Reckon if you can't find out whats wrong with it, put it back to standard and take it to another dealer :icon_thumright:
 
IH786 said:
Welcome to the forum mate :) Good to see you took my advice and joined up!

Reckon if you can't find out whats wrong with it, put it back to standard and take it to another dealer :icon_thumright:

Appreciate the advice - put it all back to standard tonight so a visit to Reading will be on the cards if no joy on Friday
 
Did you get your S3 in Reading? Thats where I got mine.
 
The car will probably be logged as modified on the national dealer data base, they may wash there hands of you. I wish you luck anyway.

Mark
 
Dealers aren't that clever. They have only just moved on from type writers am I wrong hehehheehhe.

Should be ok.
 
There is no ways in hell that VW/VAG/Audi can wash their hands of a car with a DV mod - Ie. Forge DV. It's a better part. Plain and simple.

The VAG DV is already on revision "G" and even stock cars can go through several after 20k miles. Or worse.

Ask the dealer how many DV's they replaced in a week ? You'll be shocked to hear the answer.

My advice - take the induction mod off, leave the Forge DV on. And give them serious attitude. Quite frankly their stock DV's should almost be considered a "latent defect". Would love to see that one in court.

The Forge DV is a lot more reliable - strange issue with yours though - I'd really like to know the outcome as I've just fitted one myself after my first VAG one ripped.
 
I did argue to the dealer (Newbury Audi), that all parts chosen were based on past experience with VAG cars (ripped DV diaphragms galore), and were always suitably expensive and well considered.

I will try Reading if I get any further issues. Car still wasn't 100% this morning after a night to readapt with the battery off. Will report more later today as I'm off to Forge with the DV now.
 
Just another thought - bad fuel and octane boosters usually burn the plugs out and can cause hesitation and flat spotting.

I changed mine after 5,000km after feeling signs of the above - and it was like being handed a new car.

Set of 4 plugs should be cheap - I'd give it a try.
 
TheWusMan said:
Just another thought - bad fuel and octane boosters usually burn the plugs out and can cause hesitation and flat spotting.

I changed mine after 5,000km after feeling signs of the above - and it was like being handed a new car.

Set of 4 plugs should be cheap - I'd give it a try.

Svens' right here ...

I had a hesitation in most gear from about 4800 rpm onwards , it became progressively worse. Replaced plugs and the problem was sorted. The car had done around 8000 km.

Problem now is that i've only done about 2500km and im picking up hints of hesitations again ... so it could either be a tfsi issue killing plugs or the octane booster that's causing the issue.

Change of plugs i'd suggest heh ... I'm doing further testing to determine the source of the problem.

over and out
 
I know of 3 Forge DVs that have come loose ...I will be having a look at a mate of mines whose car is not getting the required boost as per VAG COM..seems like the DV itself has a defect in the design....
 
SSS3 said:
Svens' right here ...

I had a hesitation in most gear from about 4800 rpm onwards , it became progressively worse. Replaced plugs and the problem was sorted. The car had done around 8000 km.

Problem now is that i've only done about 2500km and im picking up hints of hesitations again ... so it could either be a tfsi issue killing plugs or the octane booster that's causing the issue.

Change of plugs i'd suggest heh ... I'm doing further testing to determine the source of the problem.

over and out

Howdy Way - did your scooby suffer from plug problems as well ? If so this might be a by product of the octane booster, or our fuel in SA is just so poor that the modern TFSi (or similar high compression ratio engine) simply needs better juice to a)perform at peak and b)make the plugs last longer ?

Other problem is that VAG logs don't seem to reveal much - which makes it difficult to diagnose. Good luck and keep us posted if you find anything ...

By the by - your bro is the man - did he tell you about "finding the lost pliers" deep deep down in the engine bay. I was impressed - he knows how to work a bit of magic.
 
Hmmm, more interesting points raised.

Got back from Forge this afternoon and as per usual their service was exemplary. They changed the DV, checked the old one, and although it had stuck they couldn't get it to replicate (I'm sure under heat and high boost pressures they are more likely to error than when at room temp under finger pressure).

They fitted the new DV, and sent me off for a test run. Exactly the same.

So they rehooked up VAG.com and not a single error code!!!

I ALWAYS run Shell 98 RON Optimax as I have heard reports that the TFSi engines just don't perform well with 95RON. Actually, to be fair its had 2 tanks of BP Ultimate, and a 1/2 tank of Tesco 99 in 8000 miles, but never standard octane fuel. I have twice used OCTANE BOOSTER, but more out of curiosity. Noticed no difference at all, but then I don't believe an ECU can adapt in 1 tank of fuel.

I will go and get a set of NGK Platinum's tomorrow morning before I run the car up to Revo. I did try some Denso Iridium's in my Stage 2 Leon Cupra R and it ran like a dog so I will stick with NGK's as they've always been faithful. With the cars service intervals being at 20,000 miles I guess I will be changing the plug every 8-10k myself if this proves to be the issue.

I've got a job interview in Oxford at 12pm, then an appointment at Revo at 2:30pm, then I'm picking up relatives from Heathrow at 6:30pm so if the car is going to break down its got plenty of opportunity - if you see a grey S3 on the M40 hard shoulder tomorrow give us a honk!!!

Thanks for all the advice guys, will obviously post up anything I find. Don't you just love searching for faults that post no DTC's!!!!!
 
TheWusMan said:
Howdy Way - did your scooby suffer from plug problems as well ? If so this might be a by product of the octane booster, or our fuel in SA is just so poor that the modern TFSi (or similar high compression ratio engine) simply needs better juice to a)perform at peak and b)make the plugs last longer ?

Other problem is that VAG logs don't seem to reveal much - which makes it difficult to diagnose. Good luck and keep us posted if you find anything ...

By the by - your bro is the man - did he tell you about "finding the lost pliers" deep deep down in the engine bay. I was impressed - he knows how to work a bit of magic.

I only ran 102 on the scooby or a heavy dosage of Toluene/ Xylene / Methanol eh. Never touched Octane boosters till the S3
 
warrencox said:
Hmmm, more interesting points raised.

Got back from Forge this afternoon and as per usual their service was exemplary. They changed the DV, checked the old one, and although it had stuck they couldn't get it to replicate (I'm sure under heat and high boost pressures they are more likely to error than when at room temp under finger pressure).

They fitted the new DV, and sent me off for a test run. Exactly the same.

So they rehooked up VAG.com and not a single error code!!!

I ALWAYS run Shell 98 RON Optimax as I have heard reports that the TFSi engines just don't perform well with 95RON. Actually, to be fair its had 2 tanks of BP Ultimate, and a 1/2 tank of Tesco 99 in 8000 miles, but never standard octane fuel. I have twice used OCTANE BOOSTER, but more out of curiosity. Noticed no difference at all, but then I don't believe an ECU can adapt in 1 tank of fuel.

I will go and get a set of NGK Platinum's tomorrow morning before I run the car up to Revo. I did try some Denso Iridium's in my Stage 2 Leon Cupra R and it ran like a dog so I will stick with NGK's as they've always been faithful. With the cars service intervals being at 20,000 miles I guess I will be changing the plug every 8-10k myself if this proves to be the issue.

I've got a job interview in Oxford at 12pm, then an appointment at Revo at 2:30pm, then I'm picking up relatives from Heathrow at 6:30pm so if the car is going to break down its got plenty of opportunity - if you see a grey S3 on the M40 hard shoulder tomorrow give us a honk!!!

Thanks for all the advice guys, will obviously post up anything I find. Don't you just love searching for faults that post no DTC's!!!!!

I still call plugs :) :p
 
+1.

My money is on a set of new, shiny plugs.

Keep us posted :icon_thumright:
 
I never made it to Revo last night as my interview over ran by nearly 2 hours and the M40 was gridlocked. So today I cracked out the toolkit and changed the plugs.

And guess what.....?

Congratulations to those above who diagnosed, you were right. Plugs. Audi swear blind I should be getting 60,000 miles from the plugs which I dispute. However I would expect 15k from a plug of this quality.

My fear is that if the plugs are taking this sort of punishment, what is likely to be happening to the valves / head?

the plugs were jet black and coked up, and even the exhaust is looking tainted on the tailpipes. I can't post pics at moment as Im using iPod touch, But will post some later. the plug electrodes did not look too bad which surprised me.

Thanks again for all the help. I will post back when I find out what has been going on.
 
Good to see you got running properly again mate:icon_thumright: But it is disturbing you had to change the plugs after less than 10k. Would be interesting to know why they needed to be changed so soon :think:
 
Excellent news matey !:icon_thumright:

But I too am now left wondering why the standard audi plugs waste away so darn quickly.

Is there any chance of getting a "plug expert" (does such a person exist?) to look at that set of yours and offer some clues ??

Mine lasted 5,000km.
 
please be aware, this opinion is not qualified and may be innaccurate:

I don't think the Tfsi system lends itself too well to increased fuelling mixtures. I am not an expert on how the fuel and air mix in this system, but since fitting my air intake and filter you can smell its running rich. The tfsi system was designed to be fuel efficient and frugal, but if you adjust the parameters it quickly seems to take its toll on ancilliaries. My concern is whether damage is being done to non consumable parts like valves etc. I will get Revo to assess the issue. Whatever is happening something is not right. Problem is there are no big mile cars to assess. Mine has done 8'800 miles (13000km approx).

Whatever the score I am not best pleased about it!
 
The answer here is to use a 'hotter' plug, or put the car back to how its maker intended it to operate.
 
Done 17,500 miles in mine. Got a Carbonio, BMC Filter and Milltek turbo back, ~330PS.

Not had any issues yet....

Would I not be seeing the signs? Never had anything other than VPower in mine though.
 
CJP80 said:
Done 17,500 miles in mine. Got a Carbonio, BMC Filter and Milltek turbo back, ~330PS.

Not had any issues yet....

Would I not be seeing the signs? Never had anything other than VPower in mine though.

330PS :hubbahubba: . You mention some useful mods, but nothing that should 'suggest' the type of increase to deliver that. I'm going to have to assume you have some other magic going on there ;-)

Have you had any issues / DTC's showing low fuel pressure? The fuel pump starts to struggle to deliver enough fuel under full load when your set up can push over 315bhp. I appreciate the Milltek will have freed things up a bit, but they are some pretty good figures, so well done.
 
Had 313PS prior to the exhaust going on.

Also got 335lbft of torque!

Never had any fault codes generated since buying the car.

I have to admit that I'm VERY careful not to rev the car until the engine oil is up to temperature.
 
my real concern is just what's causing this ...

i've done about 2500 km on a new fresh set of plugs and i can feel a hesiation sometimes under load.

can't keep replacing plugs every other month...

had my car on the dyno after getting my xhaust sytem done.

208kw / 403 nm at the wheels :)

maybe the rated plugs just can't hack it
 
Not being an expert but it looks like fueling is all over the place hotter plugs might help, maybe some remaps are better than others and it would be interesting to see if cleaning the plugs help shorterm
But certainly looks like a map issue
Normally one would expect a plug upgrade with a non standard map to cope with the different output.
The thing is incorrect ignition timing/ fuel ratios through the rev range will kill your plugs and a weak mixture could do even more damage
 
CJP80 said:
Had 313PS prior to the exhaust going on.

Also got 335lbft of torque!

Never had any fault codes generated since buying the car.

I have to admit that I'm VERY careful not to rev the car until the engine oil is up to temperature.

Nice figures, have you had the car remapped? If so which one have you gone for?

--

I'm glad the plugs sorted the problem any chance of some pics of the used plugs? I'll check mine this weekend.
 
Apologies for the delay and the lack of photos. I spent the morning at Revo yesterday, and Nick was able to point me in the right direction with respect to some pointers on the car.

1) I live quite close to where I work, and we worked out that by the time I get to work the car is still not achieving full operating temperature. As the car is running 'on choke' so to speak this means the plugs are seeing some serious fuelling exposure during this time. Nick didn't think the plugs looked too bad, but all the plugs I have had in previous cars have looked whiter than these, so to me they looked unusual.

2) All the logs pulled back from the car looked perfectly OK, so there were no signs of any long term damage. I am about to change jobs and more commuting will be required so the car will be getting more long runs.

3) Some US tuning houses have seen some issues with the reliability of the breather pipe (which sits under the engine cover in front of the head). Supposedly these can start to degrade under high boost conditions, and the internal valves can give way. This allows boost back into the engine where there should be vacuum - apologies I didn't understand the technicalities of this, so I can't elaborate further. However it is something to watch out for as this can accentuate extra wear on plugs (as well as further issues).

So the car is back on song for now, and we are happy again with what is truly a very special car. Having come from a Revo Stage 2 Leon Cupra R the S3 was always going to have its work cut out, but Revo have done an astonishing job getting this car to where it should be. The aftercare has been first class which is more than can be said for my dealer.

Actually, on the point of dealers Revo introduced me to a new Audi dealer yesterday in order that my Audi ownership may improve. Who said customer service was dead?!?!

cheers all, and may thanks for the tips / advice.
Warren
 
warrencox said:
Apologies for the delay and the lack of photos. I spent the morning at Revo yesterday, and Nick was able to point me in the right direction with respect to some pointers on the car.

1) I live quite close to where I work, and we worked out that by the time I get to work the car is still not achieving full operating temperature. As the car is running 'on choke' so to speak this means the plugs are seeing some serious fuelling exposure during this time. Nick didn't think the plugs looked too bad, but all the plugs I have had in previous cars have looked whiter than these, so to me they looked unusual.

2) All the logs pulled back from the car looked perfectly OK, so there were no signs of any long term damage. I am about to change jobs and more commuting will be required so the car will be getting more long runs.

3) Some US tuning houses have seen some issues with the reliability of the breather pipe (which sits under the engine cover in front of the head). Supposedly these can start to degrade under high boost conditions, and the internal valves can give way. This allows boost back into the engine where there should be vacuum - apologies I didn't understand the technicalities of this, so I can't elaborate further. However it is something to watch out for as this can accentuate extra wear on plugs (as well as further issues).

So the car is back on song for now, and we are happy again with what is truly a very special car. Having come from a Revo Stage 2 Leon Cupra R the S3 was always going to have its work cut out, but Revo have done an astonishing job getting this car to where it should be. The aftercare has been first class which is more than can be said for my dealer.

Actually, on the point of dealers Revo introduced me to a new Audi dealer yesterday in order that my Audi ownership may improve. Who said customer service was dead?!?!

cheers all, and may thanks for the tips / advice.
Warren

Good to see your car is running ok now mate :icon_thumright: Impressive service from the guys at Revo too. Its a toss up between them and GIAC for my remap next year :):)