I have been having trouble with my volvo 740 with a B230K engine, it has no spark (see http://www.brickboard.com/RWD/index.htm?id=617810 below for
the story). The ignition electrics have been a headache as they just don't seem
to match up with available manuals. Now I discover that instead of the Bosch EZ118K ignition system that nearly all 740/B230K volvos have. I've got one of the much rarer models with the EZ100K system installed. I can find no manuals or documentation on this apart from the fact that they exist and that the system is more typically associated with saabs. Any and all help gratefully received as I'm off the map here.

Hey, I know that this is a site for people who work on their bricks But - a dealer thchnician is good for something!

You have done what you can (or more) - I suggest that you have your brick towed to a dealer and see what they find. If you try enough stuff, you WILL find that you have a bad ECU, and STILL may not know what the problem is.
--
3 8s & 2 7s 740,000 miles total

Totally understand your point. However, money's extremely tight these days and
the volvo's a second car (well, would be first if it went). As far as my wife's
concerned if it doesn't go and can't be easily made to run then it's landfill;
she may be right (it's the equivalent but less costly equivalent to take it to an expert), but it seems to be such a waste.

Tony,
Just a thought, could it be that the pin assignment is different on the EZ11*K
power stage from your EZ100k connector. There are even different power stages with different nos. of connector pins on the "normal" models.
I would have suspect that the function of all the EZK power stages is basically the same, and any one of them could be made to work on any system by juggling the wiring.
When all is said and done, the power stage is only an electronic relay to switch the coil primary to earth just as a set of point used to.
If you are still getting a 5V square wave output from your ECU you haven`t damaged it.
If all else fails there are after-market electronic ignition systems available but you would need to check whether they will accept the Hall effect sensor outputas a trigger.
The other alternative is to fit the EZ11*K system complete from a scrap car, loom and all. At least then you would have a standard system with easily obtainable parts.
Good luck,
Colin.

It's the same power stage as on the EZ118K, which threw me at first, but I guess
is a blessing really (it also crops up on saabs). I've been a bit more careful
on my checking now and find that my voltages are in fact a bit low. I'm seeing
a 3.7 volt pulse from my ecu (and on the blue wire on the hall sensor
connector). It was sloppy of me but it's pretty much 5v on the _AC_ scale and
so of course I saw what I wanted to see. I swapped in the EZ118K ecu I have and
still get a 3.7v pulse rather than a 5v one, and similar at the hall sensor.
I can see that an undervoltage pulse would be insufficient to trigger the
power stage and hence lead to the lack of spark I'm suffering here.
So I'm guessing that there might be a 5v voltage regulator, external to the
ecu, that's not up to scratch, or something similar that supplies
the 5 volt circuitry (resistors off spec in a potential divider circuit, dying
zener diode, etc..). Any ideas??

Tony,
As far as I know there is no external 5V regulator on this system this is a function of the ECU.
Just one point though, you will not get an accurate AC voltage reading from a square wave sgnal. A normal volt meter is calibrated to read the RMS voltage of a sine wave. An oscilloscope is the best way to check it out but it might be informative to check your meter against a signal generator capable of giving a 5V square wave. You would then be able to work out the actual voltage you are seeing.
If you can get hold of a `scope your ECU should show an almost perfect 5V square wave, (well, mine does anyway!)
Colin.

No, no.. completely understand on that score. No, the '5v' (but sadly 3.7v)
pulse I'm seeing is from when I toggle the black and blue wires at the Hall
sensor connector. The pulse is of sufficient duration that the analogue meter
appears to have long enough to settle (on the order of a second). I'm _not_
trying to read the AC signal given from a spinning distributor. Now the fact
that I'm seeing such a long duration pulse off of a single brief signal being
fed into the ecu might be bogus but I'm seeing it off of two different ecu's
(I'm guessing the power stage triggers off of the leading edge and that pulse
duration is rapidly curtailed as succesive signals come from the Hall sensor
direction).

Your comment that the '5v' circuitry isn't fed from an external regulator
suggests that I should confirm that the 12v line into the ecu is at a full
12v, as I guess any shortfall to begin with will rattle on through and cause
problems.

As for getting my hands on an oscilloscope, I'd love to, but sadly is beyond
my means at present.


cheers
Tony