1999 S3 - A few questions and pictures to follow

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Barker_Tom

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Hi chaps,

I have just just bought an early, unmodified 1999 S3 (210 model) on 88K miles. It has been a while since I last owned a Turbo car, having just passed off my excellent 172 Cup in favour of the Audi.

I have a few questions to ask you guys who no doubt know a bit more about German cars than I do - Although I have done my time playing with French engines (had a whole string of R5GTTs.....) so I am not entirely simple.

Anyway...

- When warmed up my idle is lumpy, dropping between 500rpm-900rpm. Also when selecting neutral from another gear, the engine speeds drops right down to 200rpm ish (almost stalling) and then picks up to idle again.

- Boost is lumpy, when accelerating I get quite major flat spots, especially after I have been thrashing it a bit. I can hear flutter/chatter quite loud when letting of the throttle, I thought at firs there may be a boost leak, but now I think that maybe the flat spots are caused by pinking/knock sensor?? - as I am using cheap 95ron fuel (should the S3 use Optimax or equivalent?).

- It has that common sound on start up...like a bag of nails (only for a split second), but sounds OK thereafter...

I have the day off tomorow when I am changing the track rod ends and front discs. I'm also going to give the engine bay a clean and look over.

I thought it may be worth asking for advice before I start taking the inlet tract apart looking for problems.... (I don't want to break anything - I need to get to work on Thursday!).

Many thanks for any help that you can offer,

I plan to spend all day saturday cleaning and polishing the car, so I will post some pictures up.

Tom.
 
Barker_Tom said:
Hi chaps,

- When warmed up my idle is lumpy, dropping between 500rpm-900rpm. Also when selecting neutral from another gear, the engine speeds drops right down to 200rpm ish (almost stalling) and then picks up to idle again.

- Boost is lumpy, when accelerating I get quite major flat spots, especially after I have been thrashing it a bit. I can hear flutter/chatter quite loud when letting of the throttle, I thought at firs there may be a boost leak, but now I think that maybe the flat spots are caused by pinking/knock sensor?? - as I am using cheap 95ron fuel (should the S3 use Optimax or equivalent?).
Tom.
Click to expand...
Sounds like the MAF has had it. You can safely unplug it to see if this fixes the chasing idle and flat spots. Once unplugged the ECU will assume a fall back setting for measuring airflow.

If the ECU is still in OEM mode then 95ron is ok but it's still recommended to use 98ron with this engine. If your ECU is remapped then it is most likely remapped to use 98ron. If this is the case you must use 98ron fuel or risk damaging all sorts of components.
 
larsmate said:
If the ECU is still in OEM mode then 95ron is ok but it's still recommended to use 98ron with this engine.
Click to expand...

I ran mine on 95 with no problems when standard. Never noticed any gains going to the expensive stuff either.
Some do, some don't.


If your ECU is remapped then it is most likely remapped to use 98ron. If this is the case you must use 98ron fuel or risk damaging all sorts of components.
Click to expand...

To be honest, using 95 on a 98 mapped ECU will only result in the ECU retarding the timing by a big chunk...
That will protect the engine.
The downside is that although it'll ****** the timing very quickly (something like 15 degrees if it detects knock) it takes weeks/months for it to adapt the timing all the way back towards where it once was...so once you've detected knock, you have reduced power and torque for a good while.

It's highly unlikely you will actually do permenant damage on an advanced engine/ECU like the 1.8T by running it on 95 when mapped for 98. It can happen...just not likely on a 1.8T running knock sensors, as they do.
 
Thanks for your help guys.

I'll have a look at the MAF today...although i'd be guessing at which one it is - I'll start by looking on the inlet manifold as that is where my frenchies had them.


My ECU is not remapped, the engine is standard in every way.

Got a nice new toothbrush to do some cleaning with haha.

Cheers,

Tom
 
Ess_Three said:
To be honest, using 95 on a 98 mapped ECU will only result in the ECU retarding the timing by a big chunk...
That will protect the engine.
The downside is that although it'll ****** the timing very quickly (something like 15 degrees if it detects knock) it takes weeks/months for it to adapt the timing all the way back towards where it once was...so once you've detected knock, you have reduced power and torque for a good while.
Click to expand...

Is there a way to re-set the ECU and get your full power back if you have used 95?
 
I found that the breakther pipe that connects Airbox - Crankcase - Rocker Cover was completed torn in half so im just off to pick up a new one....


...anyone think that this could have been my problem...somehow I doubt it but I suppose it must be worth changing...

Cheers

Tom
 
Dodgy idling can often be caused by a failing temp sender. Common issue on vags.
 
fairzy said:
Is there a way to re-set the ECU and get your full power back if you have used 95?
Click to expand...

Unplug the ECU for 10 mins or so...
Or pull the ECU supply fuse for 10 mins or so, should do it.

I don't think you actually nee dto wait 10 mins...but there will no doubt be fome form of battery/memory effect...so give it a few mins and when you plug back in the ECU will pick up it's default tables - not the tables used as a result of detecting knock.
 
Hi chaps

thanks for your input,

- Do you mean air temp or coolant temp?

- The coolant temperature gauge doesnt give innaccurate readings, but it there two seperate sensors, one for the ECU and one for the dash gauge?

- Where about is the MAF sensor (is it the one on the intake hose between the intercoolers and the inlet/throttle body? (just behind the pasenger headlight)

- What sensor is plugged onto the radiator side of the plenum/inlet manifold about an inch after the throttle plate? I gently took mine out today and it looked a bit of a sizzled...although both wires were intact. It looks like a little resistor to be honest...i've not seen a senor like that before.


Cheers again

(P.S - I put a new breather hose on today since mine was completed shreeded wide open. Also fitted a new dump valve (710N) since mine was also nackered and it was making the chattering noise).

This site is pretty good, glad I signed up

Tom
 
hi m8 and welcome

i recently noticed the chatter on lift off and somtimes lumpy boost, i suspect, and have read one other posts (someone correct me if i am wrong) this could also be caused by the Re-circ dump valve failing (common problem) which is why many change theres to a metal forge item as opposed to the standard plastic jobby, think the standard ones are around 30 odd quid from audi,

looking forward to the pics, hope you enjoy the s3 :redrs4:

dom
 
Hi mate,

Yes - you are right.

My S3 was making very loud chatter noises when lifting off the throttle until I changed the dump valve today.

A very easy way to check if your dump valve is nackered (other than the noise) is the following...

Take it off (unscrew the three jubille clips those hold it on - one large on underneath, one large to the side, and one small on top)

then blow into the two large holes, one at a time...if you can get air through it (and out the top) then its nackered.

I couldnt blow anything through the new one that I bought today, meaning the diaphragm is sealed (required a few PSI to move it, which your lungs cant achieve!!).

Tom
 
P.s - No pics of the S3 yet...but since it is my 16th car...here's some pics of the best cars I've had to date...for the time being.

The second white R5GTT was the basis for my Uni engineering project...hence the rebuilt engine and fancy stuff...

Daytime10.jpg



RearOS.jpg




FrontOfside-1.jpg


BonnetOff5.jpg


New51-1.jpg


MsPix039-1.jpg



I've already done the three-stage meguirs treatment on my S3...but by the time I had finished it was pretty dark so no photo's untill this weekend. I've also get a pin-***** dent on the bonnet to be taken out before I grace the camera...

muwhaah...


its a Black 1999 S3 with TT wheels...
 
ok cheers for that, ill check it when i can, i read the post's properly and noticed you already fitted the new dump valve lol sounds like mine has perished tho too.

them frenchies look nice :rock:
 
Hi chaps,

Having sorted out the 710N and breather hose I was pretty gutted today when my S3 conked out completely about 200 miles from home. It would idle at all....and just stalled whenever it should have idled. I managed to limp it to a car park and had a fiddle (in my suit).

By disconnecting the sensor between the airbox and turbo (is this the MAF? - I thought the MAF was after the turbo.....?) it started to idle again. So I drive it all the way home today with that sensor disconnected.

Obviously idle wasnt great all the way and performance was way down, throttle response very sluggish, but at least I got home.



Tomorow morning i'll be having a closer look and I'll take the throttle body apart and clean it out while im at it. Is there anyway to verify is this sensor is definatly the cause?

Cheers,

Tom
 
the maf is directly after the airbox, before the turbo.

Because the 20vt runs a closed loop system with a recirc valve, putting the maf right at the airbox works best, as all the air that passed through the maf finds it's way into the engine, be it directly, or via the DV and back around again (the recirc DV vents charged air to the turbo intake pipe about 9'' after the MAF) if it ran better with it unplugged, it was almost certainly not working properly!
 
Someone above mentioned that they had 'raced' a mini...

...what exactly do people mean by this?


I hate to tread on toes etc, but I can't help thinking that is a slightly **** thing to say?

I think Mini's are quite nice but a bit common. My Clio 172 Cup is more fun to drive than my S3.

Tom
 
nothing on this thread about Mini's mate

although you did own an MG so be careful with the '****' word :laugh:
 
Lol.....It was in another post....but come to think of it, I wasted a cooper S at Goodwood yesterday so it wasn't just the Scoobies that got a bashing!! oh......and a Clio! (just) LOL
 
Opps haha

Yes - looks like I posted in the wrong thread.

I fitted a new MAF today and it made the world of difference - Awesome.

The sole reason that I sold that MG was because people always said I looked gay in it - However it was brilliant fun and pretty fast - really really great handling in the dry at least. Turned it around on roundabouts once or twice in the wet.

I took pics of my S3 today but im withholding untill I get get some better ones.

P.S - I read your post about the trackday mate - Good work indeed, seriously well done, it takes quite a bit of keen to pull your finger out and hit the track.

Tom
 
Barker_Tom said:
Someone above mentioned that they had 'raced' a mini...

...what exactly do people mean by this?


I hate to tread on toes etc, but I can't help thinking that is a slightly **** thing to say?

I think Mini's are quite nice but a bit common. My Clio 172 Cup is more fun to drive than my S3.

Tom
Click to expand...

I commented about the race with a mini because the thread asked if anybody had been involved with one...it was purely on a straight piece of duel carriage way coming off a round about. I don't see what is **** about that, your've had a clio 172 cup.... i doubt you bought that for its build quality, i'm sure at some point your've had a dabble with another obliging road user, i'm not really to sure how else to describe it......
 
I feel i must side with Leggy here..... Cooper S cut me up a few months back, off a roundabout starting from 20mph i was approx 8-9 car lengths ahead when i touched 70ish.... not even a comparison, i thought they would have been a lil better than that though
 
Sorry guys - no harm intended.

I mean that it doesnt prove anything (whats faster than what), because you have no idea how the mini was being driven. Maybe the driver had no intention of having a crack at the S3, maybe he was changing at 4krpm. Maybe the boot was full of concrete...etc etc..


Tom
 
Tom, none of us take offence on here mate:laugh:......

It doesnt say a great deal as we all know about the variables, however it does give an 'indication' as yes the Mini could be loaded with concrete etc etc, the guy who cut me up was motoring..... id bet on me winning a 1/4 mile with it based on what i know about the Coooper S's and my experience on that day...... although chuck some twisties in and the Mini (with a decent driver) would kick my ***
 
My girlfriend had a Mini Cooper and she absolutely loved it to bits - which basically puts me right of Mini's full stop.


Renault 5 GTT's are the most fun car that money can buy....(maybe...lol).

I am starting to like my S3 though now that I've driven it a bit more...its just very different to driving a Clio, which requires a different style to get the most out of!
 
yup i found that you have to learn to change gear in the S3 rather than let it red line.... my misus has mini so know what your on about....feel every flippin pot hole too!!

R5 GTT? i heard they stopped fetching money a long time ago:jester: swap ya 5 red jelly babies
 
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