Finish this sentence:

... the connections at the coil/ballast resistor of the one that has the MN (brown/black) tach wire attached (the '78-'79 B/S schematic shows this as the 1-4 bank, but, functionally, it would work the same if attached to the 5-8 coil/ballast resistor). If those seem OK, check the points (if still equipped) inside the corresponding distributor (or whatever you have firing the corresponding coil).

The tach measures the firing rate of one of the coil's primary winding -- so your symptom of "no tach + dead bank" go together well.

 

the fuel gauge!

 

if the key is still in position?
if the liquor store with my favorite beer is still open?
if my AAA card is not expired?
All of the above!
Cheers!

 

Coil, then wires and distributor cap & rotor.

 

Digiplex?

 

my underwear?

 

Yes it is.

 

Your Fiero engine's only got one bank.

 

I've seen this on two distrib setups. Do you have the R2 points on your car? Simple problem if it's just the dwell. Not simple because you need a synchrograph to check the advance curves. Does it happen about the same RPM?

Anyway, throw a dwell meter on the two distribs, and check a couple of RPM points, and check the timing. If you rely on shops to help with these tasks, there may be some checkbook fiddling in your future, but not horrible if everything else is up to date.

 

Lemmee think a second.

You have CDI - - so no points, and no R2's, but they fire from the mechanical position of the rotor (4-lobe cams) which are controlled mechanically via centifugal advance mechanism.

BUT,

You have no way for any cross talk between banks, so I would switch my thoughts to a CDI problem, or whatever is upstream electrically from the Tach. It sounds more and more to me like a unit is acting up. A dwell meter could see this as either dwell that's too great or small to trigger the tach. How hard would it be to temporarily connect the tach to the system on the other bank?

 

You are ALL wrong !

Because you forgot to phrase your answers in the form of a question....

 

Theme from Jeopardy is playing somewhere

 

If you are certain that these outputs / signals do the same job, than that's what I would try first. But be certain they are. If you have any doubts, you can call the tech line for the CDI and get concurrence.
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.....how my mistress can get a ride home so that my wife doesn't find out when she shows up to pick me up.

 

I don't have a GT4 but when that happened to me I had a drained battery caused by a loose bolt on the alternator. All of the electrics were running off of the battery!

 

Or whatever is inside the distributor firing the CDI unit. "CDI" does not always mean "no points" (just less current flowing in the points , if so equipped) -- have you ever looked inside the distributors? But you are on the right path -- swap the various components, and see if the problem follows a particular component or not.

If you want to swap that CDI units, you need to swap both the input signals (coming from the distributors) and the output signal (going to the coils). Without knowing your exact wiring, can't say that I follow your comments here 100%, but you can't just swap the connections from the CDI units to the coils (as the input signals to the CDI units will not be occurring at the right times).

 

Yes, if the white wire is a completely dedicated wire connected only to the brown/black tach wire that would be OK to swap, but you previously said this:

which I took to mean that the brown/black wire is still connected to the coil too.

However, even if you can make that swap, and then tach then works OK, you still won't know if the problem is with the (seemingly bad) CDI unit itself or the input signal from the corresponding distributor to the (seemingly bad) CDI unit is missing/bad -- Good Hunting!