Chrysler Repair: no voltage to spark coil? computer,other cause?, dodge spirit, hall effect sensor

Question
My 1995 Dodge Spirit 2.5 stopped today. I have no spark. I don't have voltage at either wire going into the coil (with key on). I believe the one wire should show 12 volts. Is this fed directly from the computer and would that need replacing? It appears that way on a diagram in one of my books.
Thanks
Tom Henricks

Answer
Hi Tom,
You are correct to be looking for voltage on the + post of the coil, but you have to watch it dynamically to see if is there when you first turn the key to run the starter motor: notice if you get it for about 1 second, not at all, or for 5 seconds of a 5 second cranking time. If not at all then you need to check the autoshutdown relay or the engine controller (computer), if you get 12v for about 1-2 seconds then you most likely have a defective hall effect sensor in the distributor, and if you have it for 5 seconds then you should also be getting spark for 5 seconds or the coil has gone bad but that might be checked first and if found to be o.k. would cause you to look at the computer. I suspect you have a bad hall effect sensor but verify that you indeed get 1-2 seconds of 12V on the + post when you crank the engine.
You might also want to check the computer for any fault codes that would shed light on your no start. "Reading out the engine controller memory for fault codes is the first step. Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine' light will remain 'on' when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for the 2.5L engines and we can look up the possibilities of what is wrong based upon what fault codes you show. There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair. Let me know the codes and I can give you some direction. The fault code for the hall effect sensor is 11 and that for the autoshutdown relay is 42.
I can fill you in on how this circuitry works later.
Roland