M30 running on 3 Cylinders !!! help

[grave77]

well I'm 100% sure of the ECU as I replaced it with one I keep at home. that was the first test I made. I installed the OEM chip but the battery is dead now and I had no time to jump start it.

fool-proof test would be an option if the OEM chip didnt fix the problem. but I was going to ask would a bad injector coil call the ECU?

also I wan't to know which relay triggers the "alternator magnatic field" terminal?

I feel that there is some relationship ... since when I manually trigger it the engine runs into 3 cylinders, so it's not the 2K rpm limit, its the magnatic field terminal that starts when I rev over 2K RPM.

[Rustam]

fool-proof test would be an option if the OEM chip didnt fix the problem. but I was going to ask would a bad injector coil call the ECU?

also I wan't to know which relay triggers the "alternator magnatic field" terminal?

I feel that there is some relationship ... since when I manually trigger it the engine runs into 3 cylinders, so it's not the 2K rpm limit, its the magnatic field terminal that starts when I rev over 2K RPM.

So I take it at this point you have not checked electrical connections with ECU?

I'm sorry - I dont know what you mean when you mention a relay that triggers "alternator magnetic" field... In theory there is no reason to turn on magnwetic field of the laternator since its used as a generator not as electric motor. If we expected to have it turn on its own by application of electricity we would have something to trigger its magnetic field... So I am quite puzzled by your message there...

There is one relay that I can see here in schematics that participates in transfer of electricity from alternator - unloader relay... Unloader relay is located in front power distribution box - right before the windshield on driver's side...

You must provide a bit more detail on what you do and what you do it with... For instance I have hard time understanding the meaning "i trigger it" - what do you trigger? and how do you perform this triggering process?

The alternator has only two terminals - for provision of electric potential - they have nothing to do with triggering magnetic fields. Perhaps you meat a "starter" instead of "alternator"? The terminal being the one on the solenoid which does use magnetic field to push starter gear???????

The "starter relay" engages magnetic field of the starter solenoid. It is located in same box as the unloader relay mentioned above. Looking from driver's side towards passenger's the relay is second from left right by the file of fuses...

I'm very puzzled by this post

Now regarding bad injector coil - Its possible that bad injector coil like everything else being observed by ECU would provide you with some message. Now question is - is it possible to have bad injector coil under your circumstances? Rather unlikely - the coils are inside stamped body unable to be accessed by any moving body, and made to withstand vibration! So chances of having the coil connection "slip" are next to impossible. Of course the coil can burn out technically speaking - but how much electricity does your ECU have to provide for that? Much more than it is capable of...

You should check all the connections to ECU for short circuits as I mentioned - that shall be your first step.

[grave77]

the alternator doest have permanent magnatic field, the small bolt gets current from the battery to generate magnatic field to make the alternator charge. and yes not turn. i tested it on the bench.

when this terminal gets power the alternator starts charging and my engine runs in 3. hope this clears what i mentioned before.

[grave77]

I have installed back the OEM chip, car stopped running in 3 cylinder mode, and the problem is precisely in the alternator circuit.

as I mentioned before explaining the magnetic field of the alternator which is connected to the smaller bolt on the alternator, the power to this terminal is disconnecting and reconnecting again making the ECU to restart or cut off and back on again ... also the dash ( OBC ) is alerting me again every time this happens with the ABS light flashing.

that's why I asked about the other terminal with the thin wire connected to the alternator. ( I called the magnetic field terminal ) since the other is the battery cable.

[Javier]

Test voltage at pin 12 of diagnostic connector (it is tied to the small bolt you said you used to trigger the alternator magnetic field). It should read about 0 volts wile the battery light is on, and quickly climb to about 12 volts when engine starts.

Pull out the unloader relay and test the engine, let us know if any thing changes.


Javier

[Javier]

Here is the charging diagram for your car that will let you understand why is it lighting ABS when alternator has issues. (zippd due to size).

I feel you have issues either with the unloader relay or the battery light, not the alternator.

Javier

[grave77]

well there was a red light with a " ! " mark that was glowing on and off along with the ABS light. can you tell me more about the unloader relay and its location?

Thanks Javier ...

[pink-planet]

i was just following the thread and reading, and I was wondering why you have such a problem with your car, isn't a car a machine where you check all the cables if they are connected to the right place? Maybe am wrong, a nice explanation will be good. thanks

[grave77]

ok ... I think now I'm getting to something ... but I have to ask something, does the RPM have anything to do with this relay?

where is the instrument cluster and the unloader relay located?

thanks mate your really helping me here !!

[grave77]

not always mate, when a machine has a controller in the middle that makes the machine behave different due to something else you don't know, here you need experience. that's why every one here ask questions in the forum.
that will also help other who might face this problem ( same machine different place )