New here and in need of boost, S2 -94.

[k.alle]

Hi everybody, I'm new here and I'm another of those Swede's

So, long time reader first time poster, here it goes.


Background:

Bought my car in April 2007, a S2 Coupe -94 with 3" catback and a 280hp chip (from Powerchip in Sweden).
I was not sure on the power of a S2 so I bought one guessing that this is how they go.

After a couple of days I started thinking that this car doesn't really pull as my old Volvo 940 Turbo (220hp chip), which really had noticeable boost to it even though it only had 1.2bar in boost pressure.
Well, then a horrible thing happened, I was chasing a 940T and i lost him at about 210+ km/h and had a real hard time keeping up up to 210km/h.
Since i have owned a 940T i knew the S2 should eat it alive, on paper.



The problem
SOOOO, I started to look into what could be wrong and here's what I have done and what's been checked:

• Changed the wastegate frequency valve.
• Boost leak tested, even with smoke, it's tight.
• Changed Lambda probe
• Removed the open air filter, in with the box
• Cleaned the Intercooler thoroughly, no sludge.
• Changed the bypass valve
• Cleaned engine breather hoses
• Changed engine breathing valve
• Changed spark plugs & the leaders between coil and plug
• Changed fuel filter
• Checked exhaust plumbing and cats, A-OK
• Checked and lubed idle motor/valve (good condition)
• Checked turbo, snug and tight

After these mods I had a car that runs pretty smooth and with 1.1-1.3bar of boost but i feel that it's really not 1.3 it's almost like a non-turbo engine, and on a few occasions I have felt the raw power of S2.
These moments has always been in late cool nights, and what a boost, wow.

But then again, next day same old same old.

It reports no errors in VAG-com (at a Audi dealer), so today i visited my car, as it is in hibernation during the winter, and measures some things up:


[The TPS]

Ignition ON, pin 2-3 = 0.424V - 4.558V

Ignition OFF,

pin 1&2 = 2000 ohm
pin 2&3 = 1036 ohm

pin 2&3 from idle position to WOT = 1043 ohm -> 1800 ohm



[The MAF]

Ignition on
pin 2&5 = 12,57V
pin 2&3 = 1,43V

Engine started, idling:
pin 2&3 = 2.39V

Engine running:

Quick blip on the throttle gave me
pin 2&3 = 2.3 - 2.9V MAX

Open throttle, about 2seconds gave me
pin 2&3 = 2.3 - 4V MAX


[Intake manifold temp. sens.]

498 ohm @ 20 degrees C


Could it be the ECU not seeing my WOT?
Funny thing is, when i test drove it tonight i pulled the contact to the TPS, and the car barely reacted to it, and the driving was all the same, i didn't make a difference.

I'm sure I've forgot about some things that I have checked and replaced to, but does anyone have any suggestions on my next move?

I really need to start spoiling my car with upgrades and fun stuff, but i want this engine problem solved first, so please help me!


Well, if you fell asleep during this post you can wake up now

Great forum by the way!


//Kalle

[urquattro-island]

sound

like you should first take focus on, throttle psensor, wire broke or is the sensor broke. Since it did no diff, diconnecting it, there could be a fault there.

[k.alle]

You are probably right.

The cable however is correctly tensioned, it pulls the throttle all the way open and the idle microswitch seems to functional as well.
Just a tiny lift with the throttle and it clicks, that's ok, isn't it?

[T2Andy]

my S2 is pulling strong even at 2500 3500 revs showing 10 psi without needing wot ,you should
feel the turbo at these revs with a chipped s2 motor ,it feels as poky as the new BMW M5 i had the other evening in the mid range but not top end obviously,oh the noise

[ericd]

I'd still like to see vag-com output/s from the car, like to know if you can trigger the wgfv etc, you checked the vacuum connections ?, clean the MAF , can u post any pics , does it have a standard wastgate setup ?

[T2Andy]

when mine runs like a NA engine its usually the recirc\dumpvalve needs a clean and the maf connections.

[k.alle]

I will order the vag-com kit shortly to see what the hell is going on.
Wouldn't the vacuum connections show up faulty at a leak test?
I've pretty much changed every vacuum/small boost hose from the intake, and corrected some weird routing previous owners had done.

The wgfv seams to be fully operational, it's about 6 months old.
If i pull the plug i get 0.7-0.8bar pressure.

I don't dare to fiddle with the MAF, it was changed only 12k miles ago, about 2 years.

Standard wastegate setup as far as i know, didn't see anything weird when i disassembled the WG head last summer.

Strange thing is, when I swapped the DV with an original Bosch new one (previous was Bosch too) and a new wgfv the car did perform real well for about a day.

I'd still like to see vag-com output/s from the car, like to know if you can trigger the wgfv etc, you checked the vacuum connections ?, clean the MAF , can u post any pics , does it have a standard wastgate setup ?

[k.alle]

I can sure feel the turbo at 2-3k rpm but it isn't the feel of that I'm expecting, hard to explain in words.
In 4-6 gear its like a non-turbo engine, it moves fast, but you ain't feeling it.

my S2 is pulling strong even at 2500 3500 revs showing 10 psi without needing wot ,you should
feel the turbo at these revs with a chipped s2 motor ,it feels as poky as the new BMW M5 i had the other evening in the mid range but not top end obviously,oh the noise

[k.alle]

Perhaps your right, i will give it a shot, and will most likely order a aluminum piston recirc.valve instead. Don't trust the diaphragm int the Bosch to much since i opened up my previous one

[EDIT]
How do you clean the DV?

when mine runs like a NA engine its usually the recirc\dumpvalve needs a clean and the maf connections.

[S2central.net]

Based on info I have - presented here - http://www.s2central.net/ds_F60_G69.html

I'd also say the TPS is bad - these are expensive... See if you can try one locally with one of the other Swedish S2 owners - if you can catch him - some of those guys run crazy power

Another way to sanity check is with VAG-COM - you should see the TPS going to 100% at WOT - if not then the ECU doesn't give you all the beans in terms of boost or timing.

Oh and with WGFV disconnected you should see 0.4bar mechanical boost - I think you must have a stiffer WG spring. Dunno what your upgraded chips are supposed to do, but on a K24 the max recommended boost in the mid range is about 1.4bar at WOT... Dropping to 0.8 or 1bar - something like that on the redline - depends on how its programmed.

Paul

[T2Andy]

The dv on mine is a alloy miltec ,you can unscrew the top and remove the piston.
my piston wasnt seating correctly due to contamination so the boost was not building
correctly i then lube the seals and clean the internals for smooth operation.

[T2Andy]

See if you can try another ecu standard or chipped and see if there is any differance,
changed my TPS and cant remember making much differance BOSCH TPS £75 ,

[k.alle]

So it might be, it'll have to wait though because im doing my brakes at the moment, and money is soon all out.

Well as the TPS roughly leaves 4.5V at full throttle (when it should be around 5) and given the fact that the car doesn't give a sh*t if the connector is in or out, it runs the same.
I doubt it sees WOT.


Yeah, there's some pretty sick S2's over here actually


VAG-com is on my priority list, so it will be ordered shortly.

The WG spring is not reinforced, I was wrong, it DOES give me 0.4 boost, sorry my bad.

Based on info I have - presented here - http://www.s2central.net/ds_F60_G69.html

I'd also say the TPS is bad - these are expensive... See if you can try one locally with one of the other Swedish S2 owners - if you can catch him - some of those guys run crazy power

Another way to sanity check is with VAG-COM - you should see the TPS going to 100% at WOT - if not then the ECU doesn't give you all the beans in terms of boost or timing.

Oh and with WGFV disconnected you should see 0.4bar mechanical boost - I think you must have a stiffer WG spring. Dunno what your upgraded chips are supposed to do, but on a K24 the max recommended boost in the mid range is about 1.4bar at WOT... Dropping to 0.8 or 1bar - something like that on the redline - depends on how its programmed.

Paul

[k.alle]

I don't know anyone else with a S2 at the moment, but the opportunity I'm sure will come.

Did you get such readings as me on your TPS?

See if you can try another ecu standard or chipped and see if there is any differance,
changed my TPS and cant remember making much differance BOSCH TPS £75 ,

[T2Andy]

Hi i cant remember to be honest but they didnt match the specs off pauls
website S2CENTRAL so i changed it .