W124 1994 320E NON CRUISE Control Wiring diagram needed / Artificial rev limit issue

[paulr230]

I recently bought an S124 1994 320e. It has had a replacement wiring harness by the previous long term owner. I noticed, when the car is below 60mph that it wont rev above 4500 and above 60 wont rev beyond 5500. It cuts like a rev limiter which I suspect is simply cutting the fuel pump. I know at idle they cant be revved beyond 4500. that is not the issue.
I have the car at a local garage and they think the issue may be a wiring harness for a cruise control car is fitted and my car is non cruise control car. They think a PIN may be different which is confusing the car and limiting the revs.
Martyn my local AO very kindly sent me wiring diagrams, but for a CC car.
Does anyone:

1. Have non CC facelift wiring diagram?
2. Have ever come across this issue before and can give some advice or pointers to me.

Thanks
Paul Santoni
Motherwell

 

[carat 3.6]

It wont be a cruise harness on a non cruise car or you wouldn't be able to plug in the throttle body, non cruise is 8 pins vs 16 pins for cruise and ASR. Most likely cause is a fault in the ABS ecu not outputting the pulsed signal to the engine ECU. The pins on the engine ecu to check are the pair which have a shroud around them.

 

[grober]

WITHOUT CC it may still have an electronic throttle body-controlled by an electronic throttle pedal rheostat. these throttle bodies wiring insulation can fail inside and can only be checked by strip down. Try Merparts Ltd Independent Mercedes Benz Specialist

 

[optimusprime]

May be in this 30 Acceleration Control System - M104

 

[Pontoneer]

I recently bought an S124 1994 320e. It has had a replacement wiring harness by the previous long term owner. I noticed, when the car is below 60mph that it wont rev above 4500 and above 60 wont rev beyond 5500. It cuts like a rev limiter which I suspect is simply cutting the fuel pump. I know at idle they cant be revved beyond 4500. that is not the issue.
I have the car at a local garage and they think the issue may be a wiring harness for a cruise control car is fitted and my car is non cruise control car. They think a PIN may be different which is confusing the car and limiting the revs.
Martyn my local AO very kindly sent me wiring diagrams, but for a CC car.
Does anyone:

1. Have non CC facelift wiring diagram?
2. Have ever come across this issue before and can give some advice or pointers to me.

Thanks
Paul Santoni
Motherwell

On a W124 cruise can be added retrospectively and it just has its own harness which connects to the actuator at one end , picks up power from the fuse box , connects to the amplifier above the throttle pedal , to the Hall effect speed sensor which plugs into the back of the speedometer , to the control stalk which mounts above the indicator stalk . The engine wiring harness you mention , given you have an M104 and will have been replaced due to the well known biodegradable insulation issue , has nothing to do with cruise control .

The most likely issue with your car is that one of the two electric fuel pumps will be faulty and the one working one won’t be able to supply enough fuel to meet peak demand . This is a very common problem.