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WRX losing power.


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9 replies to this topic

#1 Breaddrink

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Posted 15 August 2004 - 09:06 PM

2003 WRX with 25 thousand on the clock.

All started out well and the car was smooth and powerful.
This has been one of those odd problems where it's continued to get gradually worse, all the time still allowing the car to run and had me wondering if I was imagining it (why don't things ever break properly any more?), or if I was simply too used to the car to notice it's speed, but it's simply got so bad that it can no longer be this.
When we bought the car, the guy at the dealership recommended that we don't bother using high octane fuel as he'd seen no increase in performance while using it, and so I did some tests and I myself could see or feel no increase in power when using regular unleaded or high octane.

The falling in power happened pretty much gradually from that point on until I'm at where I am now.
Some days would be fine and some would be dreadful - A kind of gulping and total lack of power from the car, and a very severe juddery surge then loss in power as though I was raising and lowering the clutch while accelerating (mostly in second - just before the turbo boost kicked in).
From first, a kind of high rev down to almost zero was felt/experienced on raising the clutch to go from a standpoint to forwards motion as though the engine simply wasn't able to burn the gas fast enough...and so the upshot of the story is about a month ago I decided to try a tank of high octane again...Just 'cos.
It took roughly half an hours driving for it to happen, but ALL the power was back. The nice neck tugging acceleration you can feel, and smooth gear changes that I remembered the car being like when new.
And ever since then I've been using high octane - even tried the mid rated mix, and so stuck with the high, but the power has again been coming and going.
I even tried switching back to low octane regular unleaded just to see if I wasn't just imagining all this, and all the old problems were back. Low power and than juddering gulping lack of speed and power.

I could understand this if the car had always performed badly on low octane, but the fact was, it was great on it, and now the same problems are returning when using high octane and so something has changed. Whether this is a fuel/engine trouble or another issue that is being shown up by the differing burn rates of the petroleum, I don't know.
It's so infuriating and it's now all I can think about when driving.

This is one of those problems that I fear won't be taken seriously by a mechanic because the car runs, turbo spools up and fires, and if driven cautiously drives pretty much like your average Honda Civic (albeit with a very sensitive clutch) but it simply has almost no speed or power left on most days compared to how it used to be and the overall clutch and acceleration feel is rough and jumpy.

I simply don't want to be one of those people saying "my car doesn't feel right any more" that they tell as nicely as they can to go away and stop making it up/wasting their time.
I suppose that's why I'm asking now it's finaly reached a stage where it can't possibly be my imagination, to find out if this is a known problem on the WRX, or to gain any insight as to what it might be so I can speak with authority on the problem.

Many thanks in advance.

Rob.

#2 Guest_lothar34_*

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Posted 15 August 2004 - 11:29 PM

Maybe the fuel filter is a little clogged? That's one thing to check.

Try resetting the ECU with the high-octane gas in the tank too. There are some threads around with instructions on how to do that.

#3 kingbobdole

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Posted 15 August 2004 - 11:34 PM

I have a question. Does the problem get worse as you use the tank of gas? I'm just thinking that this may be a lack of maintance, as in the fuel filter. Speaking of civics the one I drive for work is really peppy when you first fill it with gas, but then it gets slower as you run low on fuel. This is mostly due to a clogged filter and fuel pressure. My cars with their maintained filter get faster as I run low on fuel due to weight loss.
Just a thought,
Phil

#4 kingbobdole

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Posted 15 August 2004 - 11:36 PM

wow, did we post at the same time or what?
Phil

#5 Breaddrink

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Posted 16 August 2004 - 03:02 PM

wow, did we post at the same time or what?
Phil

Thanks to both of you,

It's a thought I supose, and might explain the wavering of good days/bad days that the car has.
Though with that in mind, could it also suggest a fuel pump problem?
Not very scientific I know, but just counting, I'm getting roughly a 10 second 0-60 when things are bad.
On the truly bad days the Turbo doesn't feel like it even engages in first...the revs just get higher and higher, and a little boost is felt around 5k revs...It originaly caused me to ask them if the turbo was working when the car had to go in for a replacement radiator, but they drove it around and told me it was working.
*shrug*

And yes, the cars performance does decrease as the fuel becomes low.

Looks like the filter might be a likely cause then?

You mention resetting the ECU. Is this someting that will possibly harm anything else or void my warranty?

Rob.

#6 spanky_pete

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Posted 16 August 2004 - 03:49 PM

Resetting the ECU is as simple as unhooking the negative battery cable and pressing the brake pedal all the way to the floor. (Soft reset)

Despite what you have been told, running low octane does hurt your performance. I've ran a few 87 octane tanks through the wife's 2002 and there is a definite loss is power compared to the 92 octane we usually use. I agree with the others, check fuel filters, but also check your air filter.

Since it's still under warranty I would take it to a dealer and get it looked at soon. I suppose your turbo could be going bad, though I've only heard of a few cases of this happening.

You could also have a plugged cat or bad sensor. These cars are fairly complicated electronically, better to be safe than sorry.

#7 Breaddrink

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Posted 16 August 2004 - 04:08 PM

The only reason I don't think it's the turbo is that on good days, the pre turbo power has also returned and the turbo also works to capacity.
On bad days it feels as though theres little power for the turbo to work with...if that makes sense, and so the overall performance is simply low and lack luster.

It truly feels like the fuel isn't being fed/burning fast enough, so the fuel filter is a cheap and quick one to check out first.

Changing it over is a new one to me, but frankly almost everything is where cars are concerned.

Can you recommend any guides to changing a fuel filter?
As I understand it, the fuel lines are pressurized and need to be emptied somehow before disconnection.

Rob.

#8 Guest_lothar34_*

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Posted 16 August 2004 - 05:58 PM

You mention resetting the ECU. Is this someting that will possibly harm anything else or void my warranty?

Rob.


No, I just meant disconnecting the battery and letting the ECU re-calibrate itself. It may have adjusted the spark timing to adjust for the low-octane gas.

#9 kevinsUBARU

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Posted 16 August 2004 - 06:20 PM

you're low on boost fluid


;)

#10 slo5oh

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Posted 17 August 2004 - 01:13 PM

Pull out your spark plugs and read them. I'd simply replace them with new copper (I've never used and never will use platinum) ones.




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