M104980 early revs cutoff
 

Hi everybody!
I got the 91 w124 300ce-24 (european), and have problems with early revs cutting off. At first my car had a automatical tranny , but i swapped 717450 mechannical getrag (dogleg :D) one. With auto gearbox revs have been cut off at 7000 rpm (when i used kickdown) , but now it cutting off at 6000.
For me it's a real problem nobody can solve. After reading a lot of forums i decided the reason is in MAS relay , because it cuts off fuel pumps.
It would be great if somebody have a MAS box pin's diagram , or maybe somebody know what can i do with my problem?
In advance Great Thanks to everybody and sorry for my awful english.

I wonder if you could just jump fused ignition power to the fuel pumps and bypass the relay? Only problem I can see is if there is emergency fuel cutoff (and unsure if there is anyways) that this would no longer work.

Otherwise, to answer your question, I don't know if I could come up with a socket assignment for a Euro car, do you tink a USA chart would work?

You could probably jump pwer to the fuel pump outlet at the MAS connector.

looking at a u.s car wiring diagram, i can't see an rpm input from any trans, auto or manual. rpm comes from the speed sensor from the flywheel, then td/rpm output goes to the mas relay. i would guess the manual flywheel MIGHT be at fault. the sensor reads the ring gear teeth. maybe the wrong rpm mas relay? seen it with earlier fuel pump relays. 4 cyl relays don't play well with 6 or 8 cyl motors. good luck, chuck.

yeah ,now Iam thinkin about jumpin the MAS straight to fuel pumps, but MAS relay play enough big role , because it cuts off the fuel pumps when engine decays.

At all i found 3 schemes , as a result i think pin 7 (kickdown cutoff) needs some work , on table i saw that when accelerator pedal on kickdown it takes 12VDC.
So , when i had automaticall tranny , car made 7000rpm on kickdown , and 5500 without. Following from this i think when a put 12VDC on 7 pin , my MAS relay will let the engine make 7000 ???
But really my opinion can be real silly :D
What Guys do you think about it?
MAS box costs from 99$ used and 400$ new , so Iam afraid to broke it.

I think I would jump power to the fuel pumps (I think there is a connector under the rear seat bottom cushion which would make this easy to connect temporarily) and see what the result is. Again, for now I suggest trying this as a test to see if it solves the problem, then try for a proper repair.

DON'T put 12 V on pin 7. You WILL destroy the relay. It expects to see a solenoid hooked to pin 7 and not a voltage. Maybe it is checking for the resistance of the solenoid to increase the RPM.

Paul