K10 1.2 '92, no spark (crank angle sensor)

billgeo

billgeo

Hello everybody,

Its my first post here, so take it slow with me... :)
Also please excuse any grammar or syntax mistakes (google takes care of spelling), English is not my mother language... so...

Now, to explain my problem, and I hope some of you Micra semigods will find the time and "bless" me with an idea or two...

The car is a 1992 1.2 K10 with cat. converter (so it has the "electronic" carb, ECU and no vacuum advance)
So the situation is this, I drive home from work, park, two hours later go back, car wouldn't start!

So, I get my Haynes manual and I try and pinpoint the problem.

First of all, petrol (gas? benzine?) goes to the engine, so fuel pump is OK (also recently replaced).
Then to check for a spark, I unplug the HT lead from the center of the distributor no spark there while I crank.

I then remove and measure the ignition coil, and its within specs, so no problems there.

Next is the transistor. Now, as an electronics engineer, i know how to test a transistor, but I dont really know
if inside the heatsink is an actual transistor, or they are just calling it that (if it is, it test out faulty)
But the transistor is getting power and ground, so if its working and it gets a trigger-pulse it should work.
Anyway, moving on.

I now want to know if the ECU is triggering the "transistor" that, in turn, triggers the coil to fire the spark.
(excuse my highly non-technical terms)

So I take out my oscilloscope (after a rig it with a battery to make it portable) and trace the wire from the
"transistor" to the corresponding ECU pin, and try to see if any kind of pulse exists there.
And... no pulse there!!! So assuming the 'transistor' is OK then thats the reason for having no spark.

But here lies the true question...

Why is the ECU not outputting an ignition pulse?
Could it be...
1) faulty ECU? (are they really capable of craping out like that?)
2) a faulty sensor (a crank position sensor, or water temp maybe?)
3) other...

I know second-hand parts are cheap but a really don't feel like throwing money at it blindly...
Any input and idea is very welcome!!!

Thank you!!! :)
And I am sorry for the lengthy post...

Bill...
 
Last edited:
hi bill, do you have a photo of the inside of the distributor ? we might be able to recognise if its a similar setup to the k11
 
frank said:
hi bill, do you have a photo of the inside of the distributor ? we might be able to recognise if its a similar setup to the k11
Click to expand...

Hello frank, thanks for the reply...

The distributor on the car is this one =>
04514a1b461cd7963d72a255bbc592da.png

------------------------------------------------------------------------------------------------------------

Add it looks like this one =>

140399.jpg


For what I read, in the late models, there is an optical rotary encoder in there, and a LED/photodiode... (a LED in my '91 Micra! WOW!)

I also did some forum necromancy on this thread http://www.micra.org.uk/threads/my-micra-dont-want-to-start.36902/

So I guess the output of this crank position sensor is my next test, right?

Do you know what exactly fails in there???
 
here,s a lucas (mini) hall sensor type, if you are getting no pulse then i would be testing that personally :)

PB190324.JPG
 
frank said:
yes bill, best to remove the distributor and scope the sensor while turning it eh
Click to expand...

That's a great idea! I am tempted to go do it now!
Any tips on removing it (and correctly putting it back)? I have given my Haynes manual to a friend that needed it.
Also, is the supply voltage for the sensor +5V? (any idea about wire colors?) ?
 
So, finally got the distributor body out.

Does anybody know whats the proper voltage for the red/black wire (internal LED?) ?
Is it 5V, 12V, 2.3V ?

Thank's!
 
OK, here's an update (in case anyone was interested, or will be in the future).

I finally got replacement dizy (had to wait for it to come from Germany, used parts are that expensive around here).
And no, it does not fire! That was not the problem... (unless the used one is broken too).

BTW, how do you guys test for spark on a transistorized ECU-controlled Micra?
I mean I did it the old fashioned way, puled the HT lead from the distributor,
put it close to a metal part of the engine and cranked.
But then I read on the haynes manual that you're not supposed to do it that way!

Any ideas?
 
billgeo said:
OK, here's an update (in case anyone was interested, or will be in the future).

I finally got replacement dizy (had to wait for it to come from Germany, used parts are that expensive around here).
And no, it does not fire! That was not the problem... (unless the used one is broken too).

BTW, how do you guys test for spark on a transistorized ECU-controlled Micra?
I mean I did it the old fashioned way, puled the HT lead from the distributor,
put it close to a metal part of the engine and cranked.
But then I read on the haynes manual that you're not supposed to do it that way!

Any ideas?
Click to expand...
Frank has always suggested doing it that way :)
 
I guess there's no problem then.
I too havent heard of anyone damaging something by doing it that way.
But whats the alternative, whats the "proper" a spark without equipment?

Anyway, I guess now I am looking at replacing the power transistor or the ECU?
What would you guys replace first, as the more likely suspect?
 

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