(I bolded the important parts)
My '86 base lost all spark at once and I can't figure out what I broke
(probably air flow meter)

A while ago I was messing with the air flow meter and after reinstalling, it failed to start.
When I took it out, instead of just unplugging it, I unscrewed the screws by the plug
(because I heard on vein airflow meters that's often what you have to do),
but when I screwed it back in, it wasn't in all the way and it may have shorted when I tried to start the car.

At first I thought I wasn't getting fuel because I didn't smell any in the exhaust, I may have been wrong, but because of that,
I went and put in a new ECU, now I smell fuel, but I'm suspecting that wasn't the problem in the first place.

Now I know I'm not getting spark and just to make sure my coils haven't failed, I pulled the coils off my parts car and it didn't work with different coils.


I don't know where to go next.
I think the airflow meter may be fried, but could that cause a no spark?
(My parts car is an S5 and its able to run without the airflow meter) and if the airflow meter is the cause, is it possible to convert the S4 meter to an S5?

(I've also checked for blown fuses and there were none)

 

have you checked your distributor

 

I haven't checked the distributor. I'm not too sure how to.
(after a quick search I wasn't able to pull anything up related to specs or procedures)

but in the case that it is the distributor, do you know if the distributors between the S4 and S5 models are interchangeable?



Edit:
Originally I was trying to avoid the cas because I didn't think it was a very likely cause in this case and I don't have the tools to diagnose or time the sensor right now.

I just went out to my car and cranked it again and the tach does not move at all while cranking, but I guess that should be expected since it seems to work off of the trailing spark signal right?

 

yes and also i would have told you to cheack for fuses and your coils but you already did that so check for any loose wires maybe one got disconnected

 

Ok, thanks
I'll wait to diagnose it until tomorrow, in the sunlight.

 

sure no problem keep us updated

 

You likely damaged the AFM by playing w/the two screws on it. Replacing the ECU is of no help. With the AFM unplugged you can jumper the fuel check connector and try to start the car but do not let it run if it starts because the lack of AFM will cause the engine to run extremely rich and the manifold will begin to glow. And the AFM can prevent spark.

If the AFM was connected then w/key to on the Brown/White wire of the AFM would have 5 volts. If it reads close to zero then the unit is shorted out and it will prevent the car from being started.

 

your car also does not have a distributor, you have a crank angle sensor, which RARELY go bad

 

Thanks for all the information and sorry for this late response, but I wanted to finish up this thread with what's happened.
(the problem is solved)

First thing is I went to look inside my cas for corrosion or shorts since my multimeter was water damaged recently and can't actually test it.


I couldn't see any reason to suspect the cas, so I set that aside for then.

Next thanks to your suggestion, I went back and unplugged and replugged everything I could find in the bay and I guess either a plug wasn't in all the way or some corrosion was preventing a proper connection, but it was able to start after that.

 

Looking at the CAS pic and it appears it is off a bit.