260lemon

Hello all,

I am competing in the 24 hours of lemons and own a 1989 260E. My team and I just swapped in a 1993 300CE drivetrain and electronics and the car runs and accelerates fine but only up to 4500rpm. It seems to be cutting off fuel around this RPM and it happens in any gear. Is there a way to disable this permanently?

After reading, it seems to be associated with the ASR/ABS or park nuetral safety switch. I am having one heck of a time understanding where exactly the signal is coming from though. If someone knows how to bypass/jumper or eliminate this cut-off so we can reach redline, I would be most grateful!

Thanks in advance,

Adrian

QVHK

I am no expert in this. Maybe the tachometer had been replaced from a diesel W124 so there is a fuel cut-out signal to the engine at 4500 rpm. This happened to me before - in my previous attempt to match the speedometer with the 3.67 differential (the original differential of my 300CE was 3.07), I had once replaced the original instrument cluster with one possibly taken from a diesel W124, and I experienced fuel cut out well before redline too. Try swapping out the tachometer with one from an in-line six W124 to see if the symptom persists.

gavinbr

the limit on the M103 engine is 6200 rpm and is controlled by the "electro hydraulic actuater" or the EHA injection fuel trimmer mounted on the side of the Bosch Carb

good luck

Gavinbrhttps://mbworld.org/forums/images/icons/icon10.gif

XJguy

I dont know if this is of any help but the revs are limited when the car is in park as opposed to when its in gear. Perhaps whatever sends the signal that its not in gear (maybe NSS) is not sending the signal properly. Those NSS do tend to go bad usually due to water getting in and messing things up. I opened one up and learned that they are very simple devices and can be serviced.

On a different note, I have been trying to track down how the speed limiter can be defeated on an M104 3.2