Surging Issue - Map itself?

[fran-s3]

Hey Peeps,

Looking for any advice or direction here!

Had my 01 S3 Revo'd and annoyingly its been surging since its been done... It'll surge around 3000 - 4000rpm when changing down to accelerate or sometimes just accelerating for about 5 secs and then the boost will kick in again full swing... So it jolts you backwards with boost as expected, cuts out and jolts you forward, then kicks in again and jolts you back! Surely that's not right is it.

The turbo dies completely and it struggles to suck air in but it'll come on again full swing after about 5 - 10 secs... Sometimes I have to down change as it struggles to make any progess accelerating! (running standard airbox with green panel filter which I've checked and is fine). It's not always exaclty on the same rev range and will happen mostly in second amnd third gear gear, but roughly around the higher range...

New gen Audi MAF and NGK spark plugs were changed before remap, and so far after it I've changed the TIP to a silicone item and n75 valve but its still doing it. Im also running a baileys re-circ valve (which has some slight oil on the left side pipe is this normal?) Lifting off the pedal it's fine no jerks which would suggest the valve is fine? Checked all breather pipes and hoses for splits, and had a mechanic check to.

Its going back people who put my map on in a few weeks, could it be the map ifself?? There saying its unlikey and so are Revo, but has anyone had a problem with a map itself not uploading properelly maybe? VAG-COM shows no fault codes which is even more confussing.. I've done some power runs if that helps if anyone would be kind enough to take a look?

Please any advice would be usefull as it's doing my head in!!!!!!!!!!!

 

[scott_johnson]

Fran my surgestions would be to post this exact thread in the 8l s3 forum... youll get replies pretty much straight away!!

Hope you get things sorted mate + ill have a read through them logs you sent me!!

 

[NHN]

minimal oil is normal in all pipes of the area so dont worry & I would check the intake pipe that connects to turbo, airbox & the DV & few other pipes, if you check on I think awesome-gti they show or did show a movie of the intake pipe that collapses after a remap, it has such a high vacuum that the pipe can suck in which could explain somethings you are experiencing as when you let of the gas a bit it works normally which inturn would be maybe cause the intake is back to normal size/shape, Forge do a silicone stronger one that withstands the higher vacuum pressures, cleaning the throttle body at front of the car aswell as even the smallest gap caused over time by dirt can effect the car, the mechanical valve on the TB needs to have no gaps round it at all, when cleaned you need to do a TB alignment with VAG, check the front of the intakes for leaves & road crap, also check the side vent that feeds air to the airbox, I would suggest a CDA airbox when remapped as helps alot, might wanna check if they set boost too high, revo has a SPS dongle you can buy sometimes on flebay so you can adjust the timings, boost pressures & fuel types etc, things to check some maybe irrelevant but common, I'm leaning towards intake or maybe the N75, but intake 1st.

Where'd you get it done?

 

[Broken Byzan]

Which N75 did you put on it? mine surged with the J valve on it after the re map. Its fine on an F valve though

 

[fran-s3]

Thanks for the reply guys, much appreciated! Thanks Scott that would be really usefull mate.

Thanks Nigel. Yeah I thought exactly the same as you, and I replaced my TIP with a silicone one, my standard one was completely rubber and pants and I was 99.9% this was the problem.. But it wasn't. Yeah I also took out cleaned the TB out last weekend with carb cleaner on both sides, and reset the values on VAG-COM (it was fairly clean both sides to be honest, was quite surprissed compared to some I've heard) and again didn't cure it. Idleas slightly better though.

Yeah I also popped open my airbox and it was nice and clean, and my green panel filter was good to... You know what, I think my boost could be set to high thats one someone suggested, and it's cutting back! Tried turning ESP off in case it was that but nothing... Northampton Motorsport who did it originally are having it back for the day on Friday to take a look at it, so will let you know how it goes.. Shame they don't have a 4wheel rolling road as they'd be able to see what's going on..

Byzan, I had the original F valve, and I replaced it with a H valve version. Reason is I though it could be overboosting as the original valve wasn't letting enough boost through and reasoned this would allow for the extra boost and not surge.. The spool up is certainly more aggressive, but as a result it hits the surge even quicker now and really throws you backward, then forwards as it surges.. then backwards again as it boosts again! Crazy! Thanks for the replies guys, im not ruling out a duff coil pack/s now...

UPDATE: Took my Baileys recirc valve off over the weekend to pressure test it as suggested on the Revo site when servicing, and it held the pressure perfectly. So I can eliminate that now.

 

[NHN]

sounds like boost is to high then fella, as I cant think of anything else given your symptoms & the maintenance you have already done/changed, on revo they of course can set different boost levels anyway with the sps dongle, might be worth asking them to quickly change the boost level take it back out for test run & see if it improves at all as might be a 2 minute quick fix as that chnage takes very small time to amend.

Ah actually did I read something about the H valve, urrm now u got me thinking, gonna look about & if I see anymore info will update post.

 

[simch]

Hey Peeps,

Looking for any advice or direction here!

Had my 01 S3 Revo'd and annoyingly its been surging since its been done... It'll surge around 3000 - 4000rpm when changing down to accelerate or sometimes just accelerating for about 5 secs and then the boost will kick in again full swing... So it jolts you backwards with boost as expected, cuts out and jolts you forward, then kicks in again and jolts you back! Surely that's not right is it.

The turbo dies completely and it struggles to suck air in but it'll come on again full swing after about 5 - 10 secs... Sometimes I have to down change as it struggles to make any progess accelerating! (running standard airbox with green panel filter which I've checked and is fine). It's not always exaclty on the same rev range and will happen mostly in second amnd third gear gear, but roughly around the higher range...

New gen Audi MAF and NGK spark plugs were changed before remap, and so far after it I've changed the TIP to a silicone item and n75 valve but its still doing it. Im also running a baileys re-circ valve (which has some slight oil on the left side pipe is this normal?) Lifting off the pedal it's fine no jerks which would suggest the valve is fine? Checked all breather pipes and hoses for splits, and had a mechanic check to.

Its going back people who put my map on in a few weeks, could it be the map ifself?? There saying its unlikey and so are Revo, but has anyone had a problem with a map itself not uploading properelly maybe? VAG-COM shows no fault codes which is even more confussing.. I've done some power runs if that helps if anyone would be kind enough to take a look?

Please any advice would be usefull as it's doing my head in!!!!!!!!!!!

Inconsistency in the boost and "pull" you describe is suspiciously similar to a problem I encountered last year! Tell me, doe the car seem to be a little better and maybe more consistent when you first start it up and drive off......(not that you should be wellying it til warm!!)
I suspect your Bailey DV is faulty, some suppliers have had problems with some bad batches of the noramlly excellent Bailey piston DVs, whereby they can stick when they get to about 84 degrees (well exactly 84 degrees in my case!). My valve was brand new, played havoc with the car, and once replaced by a stock latest spec standard valve ( was a part listed for the TT QS IIRC) it has been perfect.
Feedback form the supplier, diagnosed the problem when I was there, (by putting the valve in the oven! !) was this was not the first one they had seen and it was due to some internal compnenets from a new supplier being poorly made.
Apparently it is possible to carefully remove material from the piston and it will then work ok, but I just went for a stock one.

If you still have your old one and it was servicable, try that. Whilst many change them for reliablility, at least with the diaphram valve when it fails, it si a "safe fail" and easy to diagnose. A sticking piston valve can stick open, closed or halfway and can cause turbo damage!

I know one tuner who has fitted the larger (more reliable??) bosch diaphram valve from a Mitsi Evo 8 to a few 18t motors, and they seem to work, but ehat is gains over the stock valve is debateable.

Replace stock valve is worth a try IMO.

 

[fran-s3]

Interesting really??? Hmmm could make sense... No I dont welly it when its cold so I wouldn't know... GRRRRR if it turns out to be my 'uprated' Baileys valve I'll go mental at them, bought it to make it last not break!!!! Worth giving it a go, will try a stock one... May order one from Audi today. Lost my old one!!!!! BUT I have tested my Baileys one with a pen and it seemed to hold suction with my finger and when I let it go, it popped back. But suppose this isn't at 90C!

 

[dummi]

boost leak maybe if something falls out of and back into place, or if you are using a different n75 than the one used for the remap or recommended for it you will have a different boost curve than the one programmed

 

[rabs]

Byzan, I had the original F valve, and I replaced it with a H valve version. Reason is I though it could be overboosting as the original valve wasn't letting enough boost through and reasoned this would allow for the extra boost and not surge.. The spool up is certainly more aggressive, but as a result it hits the surge even quicker now and really throws you backward, then forwards as it surges.. then backwards again as it boosts again! Crazy! Thanks for the replies guys, im not ruling out a duff coil pack/s now...

Before you do anything put a standard F valve in and see what happens. Had big issues with a car last week running a different valve than standard. As soon as we swapped it the car was normal again.

Where are you based?

 

[fran-s3]

Ok thanks everyone for your time on this and repsonces so far! Right had an interesting weekend trying to sort this issue, I *think* im closer to finder the problem... Took it back to the remap guys and they spotted the issue, but couldnt find the cause.. They went through the remap figures i.e requested and made boost and they are as they should be before the surge or hesitancy starts. They suspect either coils or MAF. They checked all my breather pipes, checked my filter and intercooler pipes and no splits in it what so ever.. They've offered me a full refund for my remap, but I really want to find the cause of the problem if I can before I do this as i believe it's not the map now.

Firstly I put my standard N75 valve back in as you guys said and its doing the hesitation again... So as advised I bought a standard DV from Audi thinking it could be a problem with my Baileys one... Unfourtantely it was no different, and the hesitation came back! So least I can rule my DV out of the equation, very frustrating though!!!!!

HOWEVER my friends came down with VAG-COM and he offered to hook it up and go through the values while I was on a run which was we did... Results were interesting!

He checked the Air Mass values or g/s value to see what it was making... My maximum I made was around 190 which I think is about right for a chipped car, before the hesitation started???

Anway here's the interesting bit.. When it started to hesitate he was watching and logging my cylinder missfire log which was group 015 and 016 I believe and it seems that the hesitation I'm getting.. IS ACTUALLY MIS-FIRES!!!! When the surge began cylinder 2, 3, and 4 all started to miss-fire and the figures were quite worrying like 3 - 4 on each for nearly 10secs and it'll struggle to accelerate but then find boost and acceleration again and they'd all clear.. (which is the hesitation I've been talking about) My friend actually said it feels exactly like it's overfuelling and obv the sparks aren't burning the required amount of fuel and hence the missfire... I've logged this on vag-com so if anyone would be kind enough to look at the log, please let me know and I can email them to you for your opinion.

So obvsiously the question now is what's causing the mis-fires? Can it be the coil packs or another faultly sensor causing it to overfuel like it is?? As far as im aware the coil packs have never been changed since 01, but I had changed the sparks to NGK Laser platinums when I first got the car on the service. At least now I know the hesitation is actually mis-fires and not my turbo acting up which is more of a relief...but still very frustrating!!!! Whats bizzare is they only missfire when they reach optimum boost it'll seem, and on tickover and normal driving there fine. I thought if it was coil packs, they'd be missfiring ALL THE TIME?? At one point all the cylinders has misfired like 4 times each continiously until the hesitation had gone...

BUT, the most frustrating thing for me is WHY DIDN'T MY CAR LOG THESE IN THE FAULT MEMORY AS A DTC as it should do when it detects mis-fires and flag it up when I check for errors? Whenever I check for faults it keeps saying NOT DTC's found!

So yeah, would really appreciate your comments please from anyone who's had the same issue, before I consider spending over £100 on coil packs! Thanks

 

[waymal]

just wondererd if you found out what the problem was, kind of gettin the same prob with my 01 s3, cheers.

 

[fran-s3]

Hi,

No not yet... Typically it's coil packs or sparks... But in my case the problem is a lot more in depth. Had the map taken off and a refund from Revo. Took it to APS in Northamptonshire who were superb.. Bascially it's doing the same thing again when they remapped it, they changed every sensor under the son and it still was doing it.. Anyway they noticed that it consistely runs really hot, like 99 on the re-circ display when you access the hidden menu.. Im getting 24 MPG on my dis when Im taking it as easy as possible in the highest gears possible which they pointed out clearly isn't right. Should be low 30's...

They confirmed it's basically it's leaning out, and Im taking the car back there which there going to keep for a few days to solve the problem. They are suspecting the fuel pump may be on it's last legs... Anyway there a really good bunch and worked overtime to try and solve it, a big thumbs up for APS so far. Will keep you posted when they've sorted it out what it was.

 

[fran-s3]

Right, just had a call from APS who have finally sorted it for me. (What a top bunch of guys there, superb service) Turns out it was my fuel pump, car was running lean and missfiring under load as it was obv requesting more fuel! RESULT!!!!!!!!!!!

No wonder my fuel ecomony has been so poor to!

Can't wait to go pick her up Sat!