E30 325i starting issues

Here's the scenario...
Car has been intermittently hard to start. Yesterday, the car stopped starting all together. I suspected the Idle Valve as it was
not buzzing as it used to however when I connected it a working car, it buzzes and appears to work. While troubleshooting, I noticed the CHECK ENGINE light is not lit when the key is turned on. I am going to check all the fuses in just a bit and am looking for other suggestions. On the chance that the ECU has gone south, will the ECU from an 87 325i plug in and work or are there problems with it being an older ECU?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
More diagnostics and the resolution...
No spark further led to looking higher up the food chain for the problem. After a little research on diagnosing the ECU, I swapped the main (Motronic) relay with a known working unit and the car lives again.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.