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Old 06-04-2010, 12:08 PM   #1
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Location: Essex, UK
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Help! Where has my power gone?!?!

Hi, wonder if anyone can help with this problem. I have a Boxster 2.5, 1998 year. I haven't used the car for a week and went to start it today and the battery was totally flat, not even any power to light the dash up. This didn't surprise me too much, as i knew the battery was a bit weak anyway. Luckily the car was indoors with its top down and unlocked so no problem getting into the car.

I connected jump leads to the car and onto a good battery in my workshop and the car started up just fine. However, when i then took it out for a drive, it was a bit jerky at higher revs, and no power at the top end of the rev range. It feels like the variable valve timing is not operating and so is very flat and lacking power at the top end of the rev range.

Now i know some cars have 'limp' modes and i wondered if something like this had kicked in as a result of the flat battery and the jump start. When i got home the battery had enough charge in it to restart ok. I disconnected it, waited a couple of minutes and reconnected, started up and went for a drive and it seemed the same still.

Now it could just be total coincidence that the VVT has packed up on its own and nothing to do with the battery problem, but has anybody out there got any advice/clues/suggestions etc. This car is quite new to me so i don't know it that well yet. Does it have fixed throttle maps, or ones that 'learn' etc??

Any help or comments much appreciated.......

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Old 06-04-2010, 12:43 PM   #2
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Your engine control unit (ECU/DME) is the learning type. It takes a few hours of driving for it to learn the air/fuel curves for your particular engine and driving style.

The car can also go into limp home mode for a number of reasons, but I think it limits RPM to 3000 in that situation.


'01 Boxster S, 51k miles
'05 Mazda 6 Grand Touring Wagon
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Old 06-04-2010, 12:46 PM   #3
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In addition to the above....I would make sure that the battery is fully charged and that it is holding a minimum of 12 volts. Try putting a plug in charger and a multi-meter on it .
2001 Boxster S 3.6L, Zeintop
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Old 06-04-2010, 01:40 PM   #4
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Thanks for the replies. Sounds like a good excuse for a long drive tomorrow to re-teach it who i am!!

Will post on here how it goes.....
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Old 06-05-2010, 06:58 AM   #5
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Been out and about in it for a couple of hours today and still no top end power. Definitely feels like the VVT has stopped working as its mega lethargic from 4000rpm up to the red line. Feels very similar to an M3 i had when the Vanos packed up.

Anyone experienced this before??
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Old 07-01-2010, 12:11 AM   #6
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Same issue is happening to my 99 boxster. Have you yet found the solution?
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Old 07-01-2010, 04:38 AM   #7
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This could be electronic or mechanical. A clogged fuel filter might do this.

Get thee to a shop and get it checked out. Too many options to sort out without having the car hooked up to a PST tool.
'97 Boxster (Black Hole for 42,000 Dead Presidents and counting) - 122k
New motor, transmission, suspension, and on and on and on it goes...
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Old 07-01-2010, 03:06 PM   #8
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That sounds like it could be a clogged fuel filter, and it's a 5 minute job, so you may as well knock it out and then go for a cruise again...
Jonny Wonder
1999 Porsche Boxster 5 Spd
Stock, with GAHH A5 Glass top.
Previous Toys:
2005 RX-8, RIP
1989 GTA, 5 Speed, Procharger Supercharger and 2 Core Intercooler, 1 3/4" headers, 3" Flomaster Exhaust, cat-delete, digital ignition, bigger fuel injectors
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Old 07-10-2010, 08:23 AM   #9
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Unplug your MAF and drive the car and see if this has any effect. I had some power issues with my '99, one of which was where it would hit the 4-5k rpm range and would just not pull through it, it was most noticeable in 3-4th gear, the power just went flat.

I tried a number of things to fix it, cleaning the throttle body and tps valve to name a few. It turned out to be my MAF, which I did not even initially consider since I wasn't getting a CEL.

Once I changed it, all my power issues went away and the car ran fine again. When I think about it, I wish I would have unplugged my MAF first as it was definitely the easier thing to do compared to everything else I tried.

Good luck with finding a fix.

- ian
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Old 07-10-2010, 10:48 AM   #10
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Actually the variocam changes over at ~5,200 RPM.. If you lacked variocam the midrange would suffer, not the top end. The solenoid that actuates VC gets zero power in the upper RPM ranges, after changeover..
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