what voltage should I have at the coil
Run a heavy clip lead from the coil+ terminal to a battery source like the starter relay battery stud and see if you have spark
Check and still no spark and still had only 3 and a half volts across the coil even with the jumper connected to the + battery post.
This seems to be a problem. Let's start over right here!!!! What you are attempting to do here is to provide good solid 12V TO the coil "hotwired" So let's do that over and check ---------maybe your clip lead is bad, IT HAPPENS!!!!
Measure from starter battery stud to engine block. You should have battery voltage, IE something about 12V. Clip your wire lead to the relay stud, and to coil POS connection. You should see a small spark if lighting is subdued. Now take your meter and make these measurements
1..........From Coil PLUS to block, should read same as battery
2.........From Coil NEG to block should read very low, less than one volt
3........From Coil PLUS to coil NEG should read 10V or more
If you leave this clip lead hooked up for a short time, 1 minute, you should feel "some warmth" at the transistor on the ECU and maybe some warmth in the coil
On a related note, clip your meter to coil + and crank the engine USING THE KEY. This should result in very close to "same as battery" voltage and in no case less than 10V
Check and had 2.98 volts while cranking and no spark
This is a BIG problem if you ran this test correctly. However, the first test above is intended to temporarily bypass this part of the problem. This would indicate you are not getting voltage during start. There is a separate contact in the ignition switch, and goes through the bulkhead connector to the ballast resistor to the plus side of the coil. That contacts entire job is to provide start voltage while the key is in "start"