kickstand80

What is the condition of the magnet in your distributor? They often break but some seem to still function where others don't. It may have some impact on the ability of the coil to pick up the induced A/C signal that the Ignition Module needs to fire.

Check out the first response to your post! AFM and CTS. My 83 gave me 7 weeks of the same thing you just went thru. I purchased the car as a non-running car for 3,000.00 after the PO spent 8,000.00 at 2 different shops trying to get it to run. This is the car and all I had to do was wash it. With there not being any way to test the actual ECU's in these cars it can be a difficult and frustrating road. Mine ended up being the ECU.

Oops, Glad you got it figured out! Free/cheep is always a good fix.

A long time ago I owned a 1967 Oldsmobile and the capacitor inside the distributor went bad and man that car ran like S--T. Spark was jumping all over the place except for where it was supposed to go. Dont rule anything out. . Do you have a timing light that you can hookup to each plug wire and watch the light flash to see if things are consistent with each plug?

Do you have a spare distributor you could swap in? Are you running the stock distributor or upgraded to a matchbox? Is your distributor ground hooked up?

It would be interesting to see how a broken magnet vs an intact magnet affects the performance of the induction pulse. Does your 83 distributor have an unbroken magnet?

Clean the connections on the AFM and the engine temp sensor that goes to the ECU. Check all the connections, ignition, injectors ect. Make sure they are clean and tight. Check the function of the distributor advance, check to see if the bearing retainer in the breaker plate is broken. A crack in the distributor cap. A bad points condenser if you are running points. Random issues are the hardest to diagnose.

Sounds like your alternator is not charging. So either you have a bad power circuit to/from the alternator or the alternator you purchased is bad. You have an external voltage regulator that could be causing the alternator to not do its job. Check to see of the parts place you purchased the alternator has the ability to test the alternator. If its good then I would suspect the voltage regulator. Dont forget that this is a 50 year old car and any if not all of the electrical connections can be suspect or corroded. Get the FSM and go thru the testing: Free download here: http://www.xenonzcar.com/s30/fsm.html

The lobes will look like bunny ears

Have you ever used one of these? https://www.amazon.com/LEIMO-Cylinder-Compression-Leakdown-Diagnostics/dp/B07W9FXKTF Everyone can use more tools!

Interesting observation. I wonder how may blown head gasket have been replaced due to too much exhaust gas in the garage!

The OHM reading changes as the engine warms up. Cold sensor high ohm. Hot sensor low OHM. I know the Coolant temp sensor and a Cylinder head sensor are really close when it comes to the OHM values. I have a 1981 and a 1983 car so I have CHTS, not coolant sensor but the ohm value should be around 7000 if you put it in ice water and around 200 in boiling water. Tried to upload a picture of the graph but keep getting errors. If you go to this site: http://xenonzcar.com/s130/FSM/1981fsm.php Look at page 18 of the Engine Fuel section you will find the graph.

A bad connection at the AFM will do this. The car will start even with the AFM wire disconnected but will die if you give it gas. I agree cgsheen1 about DONT mess with the AFM. Nothing good can come of it. They are pretty reliable and most of the time issues with these cars have nothing to do with the AFM but people go after them. Once you have messed with it it will be very difficult to get it back to factory settings and once you have figured out what is really wrong then your AFM will be out of adjustment and then it will be the issue. Vac leaks will also cause this type of engine behavior. Check the connection for the coolant temp sensor, the one that feeds the ECU.

Cylinder 3 and 4 exhaust valves are next to each other in the head, this is a design flaw and a good place to look for cracks. Have you had the head checked by a shop for cracks? That may be your only option.

My bad, I just assumed it was a ZX. The post does not say what year.

I agree with Zed. You can get the Stoichiometric (air/fuel ratio) set by messing with the AFM but you will not see any performance increases. You can only get so much air thru these things with out using forced air induction. BTW there are actually 2 screws (air bypasses) on the meter that lets you "tune" the fuel ratio. You don't have to open the cover. I understand that you have an issue and that is a worn out bushing, get a rebuilt AFM. If this thing is that worn out it will cause issues for a long time. Best bet is a new one. The yellow box is the bypass screw that is used to CORRECTLY "tune" your air/fuel mixture.

The legend is on the carbon canister. The way it is supposed to work is ported vacuum is routed from the bottom of the throttle body to the thermo-vac switch mounted in the thermostat housing. When the engine is hot the thermo-vac switch changes and routes ported vac to the distributor and the carbon canister. The vac at the canister opens the purge valve so that fuel tank gasses that are absorbed by the carbon in the canister are sucked into the intake, this was an emissions thing, sealed tanks so that gasoline fumes are not vented to atmosphere. You can bypass the thermo-vac switch, and route ported vac straight to the distributor so you have vac advance at the distributor all the time, not just when the engine is hot. Limiting the vacuum to the vacuum advance when the engine was cold was an emission thing. You may also find a "T" at the distributor that sends vac to the EGR valve at the same time as the vacuum was sent to the carbon canister. You can delete the T so that the EGR valve never opens again(also an emissions thing)

Melted chocolate ice cream=bad head gasket oil leaking into coolant. There are 2 pressurized oil ports from the block to the head and they have restriction orifice in each. I have circled them in red. Whenever I do a head gasket I use Locktite 515 light coating on the metal reinforced holes I have circled. 515 is Anaerobic (only dried when no oxygen is present). https://www.grainger.com/product/5E226?ef_id=CjwKCAjwwo-WBhAMEiwAV4dybTZyPbY-H5icKkwUzaiPmBp0NjntWAzyiw674kgkAxdh8noJCgWmJBoCWD4QAvD_BwE:G:s&s_kwcid=AL!2966!3!496359974779!!!g!1635640739665!&gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231&gclid=CjwKCAjwwo-WBhAMEiwAV4dybTZyPbY-H5icKkwUzaiPmBp0NjntWAzyiw674kgkAxdh8noJCgWmJBoCWD4QAvD_BwE&gclsrc=aw.ds There are lots of arguments about using gasket sealant on head gaskets for the L28 engine. That's a decision that is up to you. I grew up using aircraft sealant (Permatex Aviation Form-A-Gasket on my head gaskets but most of the engines I did in my early years were cast iron blocks and cast iron heads. https://www.westmarine.com/permatex-aviation-form-a-gasket-sealant-4oz-13630512.html ) I chose not use sealant (except the red circles) on my 81 N/A and my 83 N/A in the last 2 years. That was my choice. I did go back and re-torque the head bolts when the engine was warm after taking the car on a couple of break-in runs.

Aux Air Regularor.....Aux Air Valve same thing. It sitson a plate that is bolted to the intake manifold and antifreeze flows thru to help it heat up and close sooner. Look for the small hoses below the AAR.

Check the intake manifold to head bolts/nuts, the end ones have a tendency to break off and the EGR valve flange.

It is just a heating coil inside. 12v one side and ground on the other. Here is what it looks like inside on the electrical side. I put mine in the freezer and looked inside to see how far open the port was then I heated it up in a shallow pan of water to see how far closed it went. I did an OHM check on the functioning one on my 81 and it shows 40 OHMS. The one in the picture has an open circuit so it is dead.

IDK problematic wife / problematic Z? You can always sell the Z and get your money back!

Power on with key

The cylinder head temp sensor signal only leans the fuel as the engine warms, it does not change the idle. The only way your car idle changes is if more air gets in. Look for vacuum leaks. Did you purchase a new secondary air valve or find a used one? It may be incorrectly adjusted or sticky. I had to adjust mine.

Is this a test? How about a year?