scham

Hi

I need some of advice because i have quite a big problem with my w124 3.0 with KE-Jetronic and i don't have any idea how to resolve it .

Battery after one night is completly dead. I measured power consumption by connecting in series multimeter. Consumption was about 0.01 amps so i was quite suprised because thats good result. After a while I found something strange. When I started the engine, then I stoped it and turn off ignition I still have power on whole kejetronic... Idle speed valve, air flow potentiometer and also diagnostic socket (between pins 3 and 5 there is 12,5V). So I looked at OVP relay, and Voila. When i took off fuses from that relay, coils and ABS pump made "click" and power was gone I looked into diagram on OVP relay. Pin number 30 this is constant plus, 31 a ground and at the pin 15 power is only when the key is on. So I thought that something is wrong with ignition and pin 15 still have power even when key is on. But unfortunately no Even if I pull of the key and close the car, pin 15 does not have power. I don't understand how it is possible that coils are still egaged even if pin 15 does not have +12V. I changed OVP for new one but still the same.

Could you give me some advise? :-)

Thanks a lot.

Plutoe

If you want my help----post the VIN!!

scham

WDB1240311B415910

optimusprime m1

Regulator in the alternator gives this problem, and its a cheap fix .Also the charging light bulb in the dash ,is it on wnen you turn the key then it will be ok But If it is not, then it wont charge the battery ..

scham

Charging of battery is correct (about 13.8/9V at idle).

I made simple test few minutes ago. I disconnected both cables of alternator and then I started the engine. Problem did not resolved

I will try to change VR from my second benz and we will see whether it would help.

optimusprime m1

scham did you check if the bulb was on, or off , .If its not on it wont charge the battery up.

scham

Right, I replaced regulator and that did not resolve the problem.


Bulb of battery is on when I turn the ignition on and after I start the engine it goes off so I think there is everything okey with alternator and battery (yes, I replaced it too)



I don't have any other idea :/

Plutoe

These oldies are hard to search as the format has changed bla bla.

scham

Unfortunetly not, it wouldn't

First page of this text is about enrichment fuel/air mixture when cold engine is started so it is compleatly out of my problem KE jetronic is set up properly, I dont have trouble with starting cold/warm engine.

Second part about lock-out switch of lever gearbox also wouldn't help because my switch work well

I think that ignition starter switch also is good because when I turn off key, 12V goes off from pin 15 at OVP relay. I can not understand how it is possible that coils in this relay are still shorted even if there isn't any power at 15 pin... Magic.

optimusprime m1

I am thinking that you have a short in the loom in some place .Maybe engine loom .Can you see any bad , or any wires that have no insulation on them. But first,i think i said this before .If you have an earth lead thats not making contact on the body you will have no return to the battery . I know some one that could help you but he is on another forum. Very good with electronics .

jylee

Check your lower engine wire harness. It is routed around the bell housing and the alternator. If the insulations are bad, you have a short. I have to rebuild mine years ago on my w140.

scham

In m104 with ke jetronic there isn't problem with bad harness. My is in good condition.

I resolved problem in simple way. I cut red wire which is going to pin 30 in OVP and I added between it another simple 30A relay which is controlled by ignition 12V.

Everything works fine, but what IS () main issue of shorted coils on OVP? No idea

optimusprime m1

Removing electronic tems from the system when its running , is not a good idea. Read you manual it will tell you this .

optimusprime m1

Scham Lots of info -- Google search this Model 124 Maintenance Manual Index May be not right now ,,but later on it will come in.

scham

But look, when whole system works properly terms are also removing when the system is running. When you turn the ignition off, immediately pin 15 is 'dead', coils are open = no power at ABS,ASD and CIS unit. The same situation is now in my case.


Thanks for the diagram. I checked all connection in whole CIS but I didn't find anything wrong. I think that something wrong is with CIS controll unit. My friend also has m104 with ke jetronic and what I discovered - if you turn off the ignition in his car (work fine), there is still power on whole CIS system for about 10 minutes, I don't know why, but it is. After this time, coils in OVP are being opened and system is dead. There must be some timer or something. In my case it is probably broken and it don't disconnect whole system.

optimusprime m1

The ovp relay is there for the surge in power, I do know that a fault in it can cause stalling .But if you swaped it out,then i am stuck .I am back to the aternator in side you have diodes could be one is a dead . You did a check on the alternator by removing the contacts . So i am thinking about a short located someplace in the loom..Have you ever jump started your car .

QVHK

Something drained my new battery within days sometime ago. It was preceded by the radio failing to work properly, and blown fuse and burning of fuse as soon as inserting a new one. Leaving the burnt fuse un-replaced and discontinuing use of the radio did not cure the power drain. It was later found to be caused by the very delicate and expensive HiFi, subwoofer and equalizer system which the first owner installed 20 years ago where some parts of the electronic board had failed and drew power directly from the battery. Discontinued use of the system did not cure the problem, totally removing the main wires did. A carpet sweep using the fuse map with everything shut-down confirmed that everything was normal after the removal of entire HiFi, subwoofer and equalizer system. However, yours may be a different issue as in my case the power drain was rather slow (complete drain in a few days, first sign was a slow turning starter) did not cause stalling while engine was running. Battery drain and stalling are separate but can also be related but I would suggest concentrating on wiring, grounding and connections relating to the ignition and engine management systems.