SL55/63/65/R230 AMG: SL55 loosing power from time to time
06-15-2014, 05:00 AM
#1
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Thread Starter
SL55 loosing power from time to time
It feels as if I'm going from problem to problem with my SL55. After I have fixed my gearbox problem, it seems now I have a problem with the compressor.
After reading several similar problems on the forum, I'm still not sure which one is mine. It feels it could be IC pump, air intake t° sensor or accelerator pedal.
Here is what happens to me. When I went yesterday for a ride, I could feel the compressor is there, but after a few kilometer at a normal pace to let the engine warm up, then I just have the power of a normal V8 without compressor. If I stop the car and restart, the compressor is back and the car is great. It goes until I keep the compressor under pressure. If I slow down and drive nicely for a few 100 meters, I back with a V8.
Weather was nice yesterday, and temperature quite nice (around 24°c). Funny is that as I was on the highway, without the compressor, I went through a tunnel for several kilometers. The air is cooler in there and when I was out of the tunnel, the compressor was back ! but only for few kilometers.
As the day came to an end, then it started to be iterative, sometime the compressor was on, sometime it was off.
So I feel the problem relates strongly to the weather and the air t° and therefore I thought the air intake t° sensor could be the trouble maker. The problem appears engine cold or engine hot, so the IC pump is probably less likely. And as to the accelerator pedal sensor, I think it cuts the whole power and not just the compressor.
I would apreciate your views on my assumptions.
Do you know if the ECU is logging errors codes for any of those problems.
After reading several similar problems on the forum, I'm still not sure which one is mine. It feels it could be IC pump, air intake t° sensor or accelerator pedal.
Here is what happens to me. When I went yesterday for a ride, I could feel the compressor is there, but after a few kilometer at a normal pace to let the engine warm up, then I just have the power of a normal V8 without compressor. If I stop the car and restart, the compressor is back and the car is great. It goes until I keep the compressor under pressure. If I slow down and drive nicely for a few 100 meters, I back with a V8.
Weather was nice yesterday, and temperature quite nice (around 24°c). Funny is that as I was on the highway, without the compressor, I went through a tunnel for several kilometers. The air is cooler in there and when I was out of the tunnel, the compressor was back ! but only for few kilometers.
As the day came to an end, then it started to be iterative, sometime the compressor was on, sometime it was off.
So I feel the problem relates strongly to the weather and the air t° and therefore I thought the air intake t° sensor could be the trouble maker. The problem appears engine cold or engine hot, so the IC pump is probably less likely. And as to the accelerator pedal sensor, I think it cuts the whole power and not just the compressor.
I would apreciate your views on my assumptions.
Do you know if the ECU is logging errors codes for any of those problems.
06-16-2014, 01:17 AM
#3
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SL55AMG, Ferrari 348, Ferrari Testarossa, Ferrari F40, Ferrari Mondial t, Ducati 916, Indycar
Using a STAR system will give a more definitive diagnosis, which is better than guessing.
These cars are very complicated, but using the factory diagnostics is a better solution.
The most common 'loss of power' problem is usually the IC pump.
These cars are very complicated, but using the factory diagnostics is a better solution.
The most common 'loss of power' problem is usually the IC pump.
06-18-2014, 11:28 AM
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1994 E500, 2012 e63
Sorry to hear about the problems you are having, my suggestion to you would be to purchase a inexpensive scan tool that will let you monitor some of your sensors and check codes for check engine light. It is pretty much a must owning this car. I use one called scanguage and it has helped me out a dozen times.
06-19-2014, 02:08 AM
#5
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Thread Starter
Sorry to hear about the problems you are having, my suggestion to you would be to purchase a inexpensive scan tool that will let you monitor some of your sensors and check codes for check engine light. It is pretty much a must owning this car. I use one called scanguage and it has helped me out a dozen times.
08-15-2014, 05:47 AM
#6
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Thread Starter
Giving you an update on my compressor problem.
Mercedes did not spot any issue when I did the last B service with them. Ok, I also did not tell them I had a problem.
I wanted to check first if it was a pump problem and ordered the improved Bosch unit. It is identical to the OEM one and fits exactly in the same place. Installation is quite easy if you're careful with the cooling liquid ... don't do it with a warm engine !!!
It took me 30 minutes to replace the pump yesterday and I test drove it this morning. Problem is gone, the compressor now pulls all the time without any interruptions !
Thanks a lot to those that helped e identifying the problem !
Mercedes did not spot any issue when I did the last B service with them. Ok, I also did not tell them I had a problem.
I wanted to check first if it was a pump problem and ordered the improved Bosch unit. It is identical to the OEM one and fits exactly in the same place. Installation is quite easy if you're careful with the cooling liquid ... don't do it with a warm engine !!!
It took me 30 minutes to replace the pump yesterday and I test drove it this morning. Problem is gone, the compressor now pulls all the time without any interruptions !
Thanks a lot to those that helped e identifying the problem !
