s3ollie Posted March 25, 2006 Report Share Posted March 25, 2006 hi, i have recently purchased my s3 (1999 210bhp model) and have found that when changing from gear to gear the enging revs hang for a few seconds before dropping back to tickover sometime worse than others but more noticable i lower gears. also i experiance inconsistent boost say if i go along in 3rd or 4th around 3500rpm coasting then accelerate somtime it may take a few seconds to boost or may climb another few hunders or more revs before the allusive boost come in. after searching the web i find im not the only one to have this problem. I have read it could be the dv valve, soft or leaky turbo pipe, throttle body alingment, n75, air folw sensor or a relay that is supposed to heat the sensor to burn off the residue after ignition off. My question is has anyone had this problem and where should i start with the list of things to replace of check? i dont want to replace things unless faulty. also had fault codes read and nothing except somthing with passenger seat conserning airbag. help needed cheers ollie Link to comment Share on other sites More sharing options...
Paul Posted March 25, 2006 Report Share Posted March 25, 2006 Diverter valver (DV) would be my first point of call. Its cheap to replace at £15 + vat at www.vagparts.com or you could chose an aftermarket upgrade, that are typically £85-100 If after that, its not improved, then all you really can do is follow a process of illimination. Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 is it worth spending more? will it make a noticable improvment over a standard one? cheers Link to comment Share on other sites More sharing options...
Paul Posted March 25, 2006 Report Share Posted March 25, 2006 OEM valve is plastic and made by Bosch. They are a throw away item. No performance increase from an after market valve, just more robust, and servicable, when you get problems like this you can take them apart and check/service them. Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 dose it have to be a specific type to fit the s3 do you think this is likley to cure the prob or is it the first thing in a long line to check. Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 is vagparts in the UK? Link to comment Share on other sites More sharing options...
Paul Posted March 25, 2006 Report Share Posted March 25, 2006 yes vagparts are in Uk. Swindon to be exact. Their website only shows a fraction of what they can get. The S3 requires a Diverter Valve. It recycles the excess boost back into the system. DV is prone to failure, it is the first step to take. It may not be the only step required, only time will tell. Where you based. You could always take it to a tuner for diagnosis. Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 im near southampton. i had the fault codes read by a local garage to try and get the airbag light turned off but it came back with passenger seat airbag controller fault. i lost the piece of paper with the actual code but nothing to do with the engine. (its going in to the garage for the airbag fault this week but thought if its only the dv or somthing else easy to change i may as well do it my self) i have already spent about £120 on fuel this week so want to keep costs down if poss! Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 just got a dv from vagparts so hopfully its that, i had thought it is as it seems boost carrys on after throtle off. Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 do you also know if it is true that the turbo hoses collapse under vacume on the pre 2001 models? Link to comment Share on other sites More sharing options...
Paul Posted March 25, 2006 Report Share Posted March 25, 2006 Some background on some of the parts you mentioned. N249 valve is the valve that controls the Dv. It usually throws an error code if its unplugged, failed etc, but worth knowing where it is,and what it does. N249 N75 controls the wastegate in the turbo. It regulates/controls boost levels via command from ECU N75 MAF is the sensor on exit of the airbox. It measures airflow into the engine in Grams/sec. MAF Throttle body reset. This can be forced via Vagcom diagnostic software. A Reset basically involves the throttlwe flap, being retaught/driven through its range, reteaching itself fully open/fully closed. It can be also forced, by disconnecting the battery for 5 mins, reconnecting, Switch on the ignition (engine still off)and leave it on for 30 seconds. (do not touch pedals) You should hear some clicking/wirring in the engine bay, always after a battery disconnect. This throttle reset is sometimes why cars feel a bit more spritely and perky after a service. They often carry out a throttle reset. Link to comment Share on other sites More sharing options...
Paul Posted March 25, 2006 Report Share Posted March 25, 2006 [ QUOTE ] do you also know if it is true that the turbo hoses collapse under vacume on the pre 2001 models? [/ QUOTE ] Its possible. some early hoses were prone to collapse my 2003 late spec S3, was supposed to have the improved reinforced hose and it still collapsed in high ambient temps under full boost. It can happen with standard cars,(must have for Audi to change the hose design and reinforce it) but remapped cars tend to show it more due to the higher volumes of air being shifted by the turbo, and heat created in that area. I shouldnt really worry about this one, Its very distinct when it happens, its like hitting a brick wall. It happend to me, but only in extreme ambient summer temps, and even then, it wasnt regular, it happend a handful of times. I had the OEM hose sleeved, and then changed it for a Samco item. Hose Collapse vid Link to comment Share on other sites More sharing options...
s3ollie Posted March 25, 2006 Author Report Share Posted March 25, 2006 ok well thanks for your help i have ordered a new standard dv hopefully here on tuesday so ill let you know if it cures the prob. ps if i step on the throttle in a not progressive manor it almost feels like it has flooded the engine for a moment and it take a while to clear then off. do you think that sound like its down to that dv too. Link to comment Share on other sites More sharing options...
Paul Posted March 25, 2006 Report Share Posted March 25, 2006 If the DV takes time to shut, or is split internally then the boost is "leaked" away from the engine, and fed back into the inlet side of the turbo. Rather than it all going down the charge pipe to the intercoolers/throttle/engine. Link to comment Share on other sites More sharing options...
vtec_boy Posted March 26, 2006 Report Share Posted March 26, 2006 I had the same problem with my S3 and put it down to my gear changes. My last car was a Civic Type R I was used to an aggressive quick gear change to make the most of the power. With the S3 I've learnt to slow down my gear changes a little and I dont get the over-revs now. It would be interesting to know how you get on with the DV change, I might do mine too. Link to comment Share on other sites More sharing options...
NiGhT Posted March 27, 2006 Report Share Posted March 27, 2006 Yeah im interested in the outcomee also as my 2000 S3 is doin that also. First turbo car so i didnt know any different. Happens when its pushed hard near the red line in first or second and the revs just hang there even though ive already changed gear!! Keep us informed m8 cheers.. Link to comment Share on other sites More sharing options...
s3ollie Posted March 28, 2006 Author Report Share Posted March 28, 2006 hi changed the dv today and seems to have cured the rev hanging at gear change problem but i still experience lag when i dont almost red line it it the previous gear. I may also put it down to my driving style as i have recently moved from a non turbo car. if i progressivly push the accelerator it seems to minimise the problem. does anyone else experiance lag? it cant be right can it? Link to comment Share on other sites More sharing options...
Paul Posted March 28, 2006 Report Share Posted March 28, 2006 Glad the Dv sorted the hanging issue. quite often they make gear changes appear smoother as well. S3 is actually quite good at not being laggy. Standard S3 turbo is usually fully spun up at 2500-2700 rpm, and certainly full tilt by 3000rpm. A remap may add the slight appearance of lag, but it isnt really, as the remap is more powerful than the standard car at all points, its just you have more peformance to play with and you get used to the bigger midrange surge, if that makes sense. You shouldnt really need to be banging it off the limiter. Link to comment Share on other sites More sharing options...
Ben Posted March 29, 2006 Report Share Posted March 29, 2006 Get the MAF changed. Early ones are shite also. 99 models do have weak intakes, so get it re-inforced. With the new DV you should be motoring then I did all the above on my 99 S3 and that kept it sweet - until the clutch started to slip...... Link to comment Share on other sites More sharing options...
s3ollie Posted March 29, 2006 Author Report Share Posted March 29, 2006 is there a way of re-inforing the pipe or do i have to buy a kit or somthing? do i have to run it on super unleaded only? and i have just noticed that the alarm is not making a noise the indicators are flashing but no noise. is the a way of setting in it vagcom or is it likley to be focked Link to comment Share on other sites More sharing options...
Mollox Posted March 29, 2006 Report Share Posted March 29, 2006 Most tuners will drop a steel ring into the pipe which will rest against one of the sensors (fear not) and stop the pipe from collapsing. Its literally a c.2in section of exhaust tubing and they should charge you buttons, if that. I have this on my car Link to comment Share on other sites More sharing options...
Paul Posted March 29, 2006 Report Share Posted March 29, 2006 This is where the hose tends to collapse at 5,000 rpm in extreme temperatures. this is a late hose which was revised to supposedly stop this (my S3 is a 2003) but when remapped, its obviously still a problem. Occasionally at around 5k you would feel the car slow and feel restricted. much like someone standing on a hose pipe, and strangling the flow. This is where AmD fit their sleeve. and a look inside, bending open the larger end to view it. some may recognise it as the perforated inards of a milltek Link to comment Share on other sites More sharing options...
Paul Posted March 29, 2006 Report Share Posted March 29, 2006 Ive now fitted Samco Hoses, and another TSN'er is making use of the sleeve. Link to comment Share on other sites More sharing options...
s3ollie Posted March 30, 2006 Author Report Share Posted March 30, 2006 after fitting a new air flow sensor toady at a cost of around £90 it has fixed any issues i had and now feels like a new car. when i asking at the audi parts desk if the air flow sensor is a problem with the s3 i was told "its a stock item!!" & the problem is "across the range" So all i can say is if you are experiencing irratic behaviour from your vag engine check / replace the air flow sensor Link to comment Share on other sites More sharing options...
vtec_boy Posted March 31, 2006 Report Share Posted March 31, 2006 Thanks for this info guys, I'm going to change my DV soon to try and rectify my "revs hanging" problem. On a few posts I've read about the Forge Eliminator DV, anyone have any comments on this particular DV? I dont want one that makes a boy racer sound, but wouldnt mind a little noise... Link to comment Share on other sites More sharing options...
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