LACK OF POWER PLEASE HELP - Benzworld.org

AMG_BLACK · 09-16-2007, 01:10 AM

I have a 02 SL500, and I feel that there is something wrong with it. It is a V8 with 302HP but it feels like an SL350. It certainly drinks enough fuel averaging 12mpg in town !!! I wouldnt mind if it felt fast. But it just doesnt. I know my last car was an e55 amg BUT i had and E500 with the very same engine only about 6months ago!! Now that 211 e500 felt fast!! and used to give me 15mpg on average. Is the SL a heavier car. I dont have any misfires and th engine is silky smooth. I drove a bmw 645ci yesterday and that felt lightening quicky yet only has 4.5 liters!!!! HELP I love my SL but the lack of torque/feeling of power is getting me down... have searched most forums but cant find anything related !! A friend of mine who has a bmw 330ci even said his car feels quicker. I think the best term for the problem is sluggish but please not there is no MISFIRE and I had it on WINSTAR only last week and there are no codes in the ECU. THis engine has gone in a lot of vehicles.. someome must know. Oh just one more thing. I used to light up the tyres when taking a right turn in my e500, the SL barely manages a little slip. The power just feels not there. HELP PLEASE !!!

dragoncoach · 09-16-2007, 01:56 PM

When was the last time it was tuned up? Sometimes all that's needed is a changing of the plugs or something very minor. Have your mechanic check it out.

Fehmarn · 09-16-2007, 04:11 PM

Hi AMG_BLACK,

Have you tried timing your car - it should do 0-60 in just shy of six secs.

One of the problems with the way this car is engineered is that is delivers in so refined a way, that you simply don't realize what's happening, because it doesn't feel as you would expect.

A comparison with the 645 will yield nothing, unless you drive them side-by-side - Beemers are designed to deliver a very direct response from the car and the road to the driver - while a Merc tries to do just the opposite.

And 12 mpg is not totally out of line for an SL in the city, either. Have you taken a reading over a longer stretch? And are you doing it "by hand" i.e. running the figures in Excel or with a calculator? The on-board computer will most definitely give you false readings if you've put wheels with a different circumference on the car.

How about top-speed? (Provided you're in a place where you can try)? The top speed on mine gives me 161 mph (260 klicks ph) at 5,000 rpm in fifth gear. (Electronically locked German spec car).

You could also try a dyno run - but bear in mind that the manufacturer listed horses for your car (306 hp) will NOT show when you take the reading at the wheels - expect 10% - 15% less, so it might be adviseable to shop for a place that has tested other SLs AND is willing to let you compare to those results (and when you do this, please be kind and give the engine a decent warm-up run of no less than 20 mls). And don't trust some hack with a cheap outfit - the unit should be outfitted with decent fan driven air supply, both for cooling and for accurate oxygen rates - and they should know how to adjust readings for altitude compensation.

Good luck - and let us know what was wrong with your baby

Chris

AMG_BLACK · 09-16-2007, 11:36 PM

Thanks for the info !!! Will try some of that stuff.. but before that Im gonna go and testdrive another sl500.. just to see if its the same... if it is... then im extremely dissapointed with the power feel... i think you maybe right and there might actually be nothing wrong... will let you know !!! PS Is an air flow meter a common problem on this engine?????????

Fehmarn · 09-17-2007, 12:38 AM

Quote:

Originally Posted by AMG_BLACK

Is an air flow meter a common problem on this engine?????????

To my knowledge extreme loss of power occurs, when charged engines run in "limp-home" mode - this can be caused by a faulty flow meter, but the 500 isn't runing a charger

AMG_BLACK · 09-17-2007, 03:25 PM

Driving the car home tonight - it felt more powerful... i think it might just be the lack of power from the E55 i am feeling. Is there any easy way to increase the power wothout spending too much money. Can a tuner upgrade the ECU and what kind of gains will i get. Also i think the other problem maybe that the gearbox ecu does not changer up fast enough- its like it has a very slow shift programme set. Change manually and she flies a lot better.. what can be done about this???