Well the car doesn't seem to have that same get up and go as it once use to have...

117000kms
2002 S, 15% pulley, CAI, Brand New P.Plugs, and Cat-back Exhaust.

Air Filter was just cleaned, Plugs recently replaced, oil change not to long ago, and I'm wondering what it else it could be...

Oh new tensioner / napa belt 535 (2 weeks old).


Fuel Pump? Cost?
Fuel Filter? I'll do the DYI if this could be the culprit..
O2 Sensor(s)? Unsure as to when it was last done..

Tire pressures are fine as well.

 

Your probably just used to it. It happens. Drive another slower car for a while then get back in and it will feel more snappier

Reset the ECU:
Hold odometer button and turn on key, the display will say test, push the button to 19 wait and it will say on off on off, push it when it says off then scroll to 21 and wait. It will say reset and then hold the button down for 2 seconds and your dash will make a funny noise. Then it is reset and it will relearn a bit.
If this doesn't work just disconnect the Positive battery terminal for a bit.
Help me out if I got it wrong!

 

Could be a BPV issue ...

 

No thats the right way, I did that yesterday too...just forgot to mention it - sorry.

BPV ? Sorry not that car savvy?

 

IC boots leaking?

 

Definitely could be Bypass Valve (BPV) - a buddy here had his fail recently. Net result - S that drives like a Cooper because it never gets boost. Do you hear / feel the supercharger like you used to? Or does it sound / feel "muted"?

 

Where and how do I check to see if the IC boots are leaking?

And yes the s/c does not seem to pull or sound as it once did.

 

Boost gauge would really help you in seeing what's going on. (If you're making the appropriate amount of boost or losing some, somewhere...)

I've gone from 15-16 lbs to 12 lbs of boost, and I've noticed a huge difference....

 

Not saying this is it...but this happenes to every car I own..did it with my Vette, then added a Twin Turbo, it was fast enough when I first put it in now it feels slow but the dyno says otherwise

 

What does reseting the ECU do? When should one do this?

 

If I'm correct, your ECU has adaptive properties, so it learns how you drive. Well, if you do a lot of city driving, you're not beating on your car per say, and it's a bit sluggish (for me). If you reset, it clears the memory allowing it to be all ***** to the wall (for a while, unless you're beating your car around a track all day ). Again, I'm not 100% sure, but this is my interpretation.

 

Thanks, Ill give it a shot today.

 

This sounds more and more like a bypass valve issue or boost leak... yeah, a boost gauge or scangauge would help to diagnose... do you have a local club? Check around and see if anyone has a ScanGauge you can borrow - will quickly tell you what's really going on with boost...

 

I have a ScanGauge 2, what am I looking for when looking at the gauge?

 

MAP - Manifold Absolute Pressure. This is boost + atmospheric pressure. depending on your altitude, with your mods, at max boost it should be about 28-29. If it's significantly lower, you may have a SC, BPV or other boost problem. If it never gets above the teens, your BPV may be stuck open. Note that when running under vacuum, it will be less than your atmospheric pressure (may go as low as 6-7)... so normal range would be about 6-7 up to about 28-29...

 

Well it stays around 6-9.9 when driving around town when I push it alittle more its in the teens, and when I floored it the max I hit was 27.6 just before 6100 rpm.

 

I saw this on tv once on a 'shade tree' show, seemed like a really clever way to test for a vacum leak. Like at IC boots. With car running, slightly open the valve on a propane torch WITHOUT lighting it! DUH. Wave the escaping propane around suspect joints. The vacum sucking pulls in some propane and the rpms rise a tiny bit. You hear it and there's your leak...

Please DON't try this unless someone else more knowledgeable confirms this would be a OK test. Sounded good to me if careful but I never researched or tried it, just one of those things you tuck away and hope to recall if needed some day.

 

Sounds like you're boost is in the right ranges... could still have a weak BPV spring which would reduce the amount of time you run in boost. But really doesn't seem like boost is your problem, based on what you're seeing on the Scangauge...

 

BPV from Detroit Tuned be a good choice?

 

Others may be skeptical about this but it really makes for a stronger throttle responce from my past experience. It's a good mod

 

To diagnose a fuel delivery concern: observe the long term fuel trim value on the OBD-2 scan tool; the numbers will be more positive when the engine is placed under load as the ECU extends the injector on time to compensate for a weak pump or blocked filter.

To diagnose a lazy O2 sensor (precat): Observe the O2 parameter on the OBD-2 scan tool; the value should fluctuate between .2-.8 volts at idle. If this action is present then view the STFT (short term fuel trim); this value will be displayed as a percentage, if the max and minimum peaks are +/- 8% or more the O2 is lazy and so will be the engines response.

To measure vacuum: connect an old fashion vacuum gauge to a vacuum source under the hood (the vacuum hose that goes to the fuel regulator on the fuel rail for example) using a tee so there are no vacuum leaks. At idle the vacuum should be between 17 to 22 in/Hg. If this is so the mechanical integrity of the engine is good.

Also measure the same value (MAP) with the KOEO using the OBD-2 scan tool. This reading will report the atmospheric pressure which changes slightly with altitude; start the car and record the same value with the engine at idle, subtract the value with engine running from the value with engine not running.

The result should be equal to the value read on the vacuum gauge under the hood taken previously, if they are not the MAP sensor could be skewed which can also produce low output.

The cooperS has two TMAP (temperature manifold absolute pressure) sensors, in one location the temp component is not used. They can be swapped to verify a suspect sensor. Also compare the IAT (intake air temperature) value to the ECT value when the car is cold (overnight cold soak) these values are also obtained from the OBD-2 scan tool; they should be within 5 degrees of each other, else I would suspect the ECT (engine coolant temp sensor) which play a very important role in the fuel equation and weather or not the car goes into closed loop operation. I hope this information helps and is not too confusing.

Also resetting the ECU by disconnecting the battery for an extended period will clear the learned values for the fuel trims. The reason the system is capable of learning is because things can change over time, for example fuel pressure and other mechanical attributes; the ECU has the ability to compensate for the changes due to age and still maintain the air to fuel ratio at 14.7:1 which is ideal for the cat converter to do a good job at cleaning the exhaust as well as a good ratio to ensure all of the fuel is consumed in the combustion process and produce good power. If an item that affects the fuel ratio is replaced then the system should be reset so as not to employ old values; at this point the system will relearn the new values required. If the system is reset with no other changes made the it will have to relearn and get back to the same point where it was, this may take a couple days of driving, and the car may idle / run a little rough until it learns! This is normal.

 

frenchie, that post ROCKED

I gotta print it... the first clear, concise guide to troubleshooting those OBD-II values that I have seen here... GREAT JOB.

 

Ireset my ecu before every track day and every auto x ...
I think it helps.

A spray of starting fluid on the ic boots while the engine is running will help find even a small leak... propane is to subtle ...

there are a bunch of threads on the BPV ...
But to check the spring you can ziptie it shut...


A scangauge has to be programed to read boost.
map is not boost.
MAP would be hard to read and track a IC BOOT LEAK

 

I'm the guy blimey is talking about, 2006 S, felt great going to work, Poo coming home, I could only guess it was a complete or partial loss of boost. Confirmed when they changed the Bypass Valve and it was back to normal.

They also replaced the clutch and T/O bearing as well as the collet as they said the clutch was slipping.

Hope your problem/expenses are small. Peter

 

Actually I was talking about another guy.

But your story works, too!