Anyone know what year they stated to install computers into Firebirds and Trans Ams? I have an 1984 Trans Am with a 305 V8 4BBl carb does it have a computer?

 

All third gen cars had computers.

Tom

 

Actually, alot of the 1980/81 Camaros (maybe Firebirds too) had some rudimentary computer controlled stuff. Not sure what it was though, but I've seen a few '80 and '81 Z28 Camaros that had computer controlled parts. Just dunno what the computer controlled, lol.

 

EFI and ignition I would imagine....even in the early 80s. We didn't have Caddie's HT4100 yet or their computer controlled stabillitrack
hehe

-B

 

Wasn't EFI. Was a 4bbl carb and vacuum advance dist. I know, because Thats what my engine came out of.

 

My 85 Berlie LG4 didn't have a computer... I think a lot of Canadian (carb'd) cars did not have an ECM

 

So in other words I have computer controlled components? Ok that's cool do you guys know exactly what is run by it? I just want to know because I plan on doing a overhaul this coming winter. I just picked the car up off of my friend. All in all the car is in really good shape, especially considering I'm form Ohio the salt capital of the North Eastern states.
thanks guys.

 

81 Camaro was the first year of the computer, was in the console.
I think the 80 Turbo Firebird was the first year for that car.

The computer will be behind the dash, were a glove box is in a "normal" car

 

I agree that Cdn carbed cars (and probably other export countries) do not have computers. Mine doesn't.

 

Is Minnesota the salt capital of the Midwest then? Anyway, I'm sure my Olds had a computer for the V6, but that was long ago now. I had the manual and onboard diagnostics for my Cadillac but nothing for my 89 so far. I'm going to have to get to the root of the poor idle problem; at any slow speed (even under acceleration) it hesitates. I've been hearing different advice from different people, supposedly in the know, so I understand it's not easy to diagnose

Bill

 

I have an '84 Firebird that I'm restoring. It has a computer that controls at least the carburator (it's an electronic feedback unit that has some kind of variable mixture or power valve controlled by the computer), the distributor/timing (no vacume advance canister on this distributor, it's all computer controlled), and I think it also reads the oxygen sensors and likely a throttle position sensor as well to determine timing and fuel mixture. There may be other things like coolant temp sensors, etc. thrown into the mix. I'd check it physically, but it's in the shop to be repainted and have some body work done to it.

The previous owner replaced the stock carb with a non-computer controlled unit. It runs, but not great. I'm rebuilding the stock unit to restore the computer control and likely get back the performance the engine was designed to deliver.
Keep us posted on how this vehicle turns out. Since it's an 84, I'm interested! Brad

 

LG4's don't, L69's do.

 

It (84 Bird) may seem quite old but my 1984 Biarritz Eldorado had the 'infamous' HT4100, or High Technology 4.1 V8. This employed GM's sophisticated computer control and on board diagnostics at the time, and I had oxygen sensor problems on mine so I can find that easy to believe. It used checksum data, if you will and displayed error codes for discrepencies. With a service manual you could narrow down the problems. It could've still used a trusty 'ole big block or something as that car weighs ALMOST 4000 pounds (3700)! hehe

Bill

 

What exactly does the computer control in a 1984 Trans Am LG4?
Does anyone know?

 

Ziddyan- Exactly what I posted earlier. My 1984 Firebird uses the exact same engine and controls that your 1984 TA does. How do I know? I just pulled the LG4 305 V8 from a 1984 TA to rebuild it for my 1984 Firebird. Same engine, same controls, same everything. The only difference is that the TA comes with the cowl induction hood if I remember correctly, for additional fresh air at wide open throttle- nice system by the way. Therefore, the computer at a minimum controls your 4 barrel carb with the electronic feedback system (you can tell by looking at the top of the carb and noticing the plastic elbow connector (usually blue in color) that sticks out the top for the electrical connections to the computer. It controls mixture from what I understand. It also controls the spark advance as you will notice that there is no vacume advance canister on the side of your distributor. It reads info from the oxygen sensors and supposedly there is a throttle position sensor on the carb that it reads. Mine has been removed, so I can't verify that, but my book mentions one. You might get a Haynes or Chilton's manual as they would describe the system in more detail that I can at present. Good luck and keep us posted. By the way, if you ever get rid of the computer controlled carb, you will likely have to ditch the computer controlled distributor and go to a stock vacume advance distributor to get it to run correctly. Someone else will have to give exact details. Brad

 

Just a few other insights from one of my manuals on the Firebird/TA.
The computer senses the MAP (Manifold Absolute Pressure sensor), sometimes called the vacume sensor... it's usually mounted on the firewall and uses it's readings to monitor the intake manifold pressure changes that are a result of varying engine load and speed. This is used by the computer to control fuel delivery and ignition timing.

The computer also looks at the coolant temp sensor to tell the engine temperature which again is used for fuel delivery and timing settings.

As previously noted, the oxygen sensors are monitored and their output is used to control the fuel/air ratio for the engine.

I mentioned the throttle positon sensor and my book says that this is only applicable to fuel injected engines, but I am sure there was some mention in another reference book to it applying to certain carb models.

The computer also monitors if the air conditioning is on and adjusts the idle speed so the engine runs faster and doesn't die or run rough from the additional drag when the AC gets switched on.

Supposedly there is also computer control of some of the EGR valve functions. I found reference to a solenoid controlled by the computer to control the EGR flow. I'm not positive this was on the 1984 versions though.

The computer also controls the air injection or smog pump control valve that controls the flow of air to either the catalytic converter or the air cleaner if the temp becomes too high in the catalytic converter.

That's all I could find for right now. Essentially it controls the timing and fuel delivery as well as some of the smog equipment by monitoring various sensors all over the engine. I'm not sure if the 1984 has the spark knock retard feature. I don't have my car here to check if it has a knock sensor in the block, so I am unsure if this is on this year or not. If it is, the computer senses the knock through the sensor and drops the timing back so detonation doesn't occur in the engine.
Hope that helps a bit. Sorry to be so long winded!
Brad

 

My Canadian L69 car does... so I agree.

 

Interesting! I wonder why?

 

Thanks guys I appreciate it.

 

No problem, any time. We are all here to help each other. Chime in if any of us can be of assistance. By the way, keep me informed of how you do with your car. Since it's the same year as mine, I am interested. Good luck to you! Brad

 

L69's used them to keep the hotter cam and carb/ignition settings in check.

 

Well right now i have a little work to do to it befoe I do anything extreme. I have a littlbe body work to do, and I have a short to find. The underneath of the car, and body are in really good shape it just needs some good old fashion TLC.
Thanks fellas