Just bought a 93 SL600 with the following things done.
Inyectors cleaned.
New Spark plugs&cables.
New fuel pumps&filter.
MAFs checked and cleaned.
IATs checked and cleaned
New ign caps&rotors.
Vacuum lines checked for leaks. Fixed a loose connection on right side.
It runs and idles fine, but it lacks power over 5000 rpm, so badly that sometimes it doesn't go over 5500, so it doesn't upshift when in kick down.
BUT, sometimes, it goes fine, revs quick and easy over just 6000 rps, shifts up and the fun goes on till next shift..
This is really a shot in the dark, so disregard if it's a bad suggestion. But I would check if the fuel pump relay on your car has a cut out on a certain RPM, and this is a sign of it going bad? If you get the part number and google you should find out if this FPR work that way.
You didn't mention engine harness, and I'm sure you are aware of the issues on the '93 model year... If it's original it will start to act up on you sooner or later..
Thanks for the input, but it is not a bucking problem. it does not hit a wall, it is a progrtessive loss of power..
And yes. I am aware of the problem, but as long as I know, the cabling issue was corrected by the previous owner, who was also the owner of a MB dealer in Madrid, where I bought the car.
If this only occurs with the engine under heavy load you may have a bad catalytic converter. A way to test would be to create an exhaust leak by loosening the bolts that connect the downpipes to the manifolds and see if this corrects the problem.
Yesterday under normal acceleration nothing happened, except a deep growl noise. After 2 or 3 secs, it started pulling again as normal. Did it twice in a short period of time. Thinking it could be an EGR valve sticky, I disconnected the vacuum lines to keep them closed. It worked fine for a while. I think it could be a cylinder bank misworking.
This morning at cruising speed, I had the same feeling this morning. I could see the L/100km indicator bouncing from 10 to 15 L, which could mean one of the ECUS is told to stop injecting..
Hope it is not a CPS problem.. They are really difficult to reach.
A bad CAT? Um. I can check inside with a videoscope
Remove the false upper firewall to gain clearance at the rear of the engine and you will easily see the passenger side CPS. The driver's side is accessed from below and is R/R mostly by touch.
Ok. It doen't sound too hard then.
I have purchased 2 cps right now, but I could not find the MB reference.. Most similar is Bosch 0 261 210 049, which I don't know if will work.
Yes. You are right. As soon as I have some time I will buy the parts and build the thing.
Anyway, I inspected closely the cabling, and It is brittle and cracked all around, so obviously it has't been changed. Bad thing.
Even if it is causing the problem or not, it has to be corrected.
Time to (also) dive in the forum and see which remedies are available.
So nightmares come true. I can hardly believe it was still running quite happy.
Opened the ETAs amd foumd the usual horror story inside. Rewired and run the left one.Finished today the right one.
Maybe it is also time to check the MAF harnesses.
Both MAF cabling completed. Run from MAF to ECU. Tested today.
Now it feels like it lacks power, and after a while, it pulls like it should. It does not feel sudden. It is more like it "recalculate"till it is fine. Very noticeable in 3rd gear. you really feel it starts pulling more and more, until it goes fine. After that, it went fine the rest of the morning (80km).
I am going back home. I will see how it goes again.
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