arkus Posted March 26, 2016 Report Share Posted March 26, 2016 there is a box about 9.75"x1.5" bolted to the underside (passenger side) of the dash of my '83, finished with a "push-on" plastic cover the same color as my dash. it has a partially unreadable gm label on it which doesn't indicate it's function. it has a number of wires coming to it that plug into two terminals. would really like to know exactly what it does. thanks for any help. Link to comment Share on other sites More sharing options...
popeyesteve Posted March 26, 2016 Report Share Posted March 26, 2016 That big ugly box is your ECM (electronic control module). If your car still has its electronic feedback Quadrajet, computer controlled ignition , lock-up torque convertor and functioning "Check Engine" light, that box is what controls them. If your car has been converted to conventional carburetor and ignition systems, then it is just dead weight. Link to comment Share on other sites More sharing options...
arkus Posted March 26, 2016 Author Report Share Posted March 26, 2016 i kind of had an idea it was linked to the ignition. the check engine lite has not worked during my tenure. everything is "as built" on the car so i best leave it all alone as the car functions very well. thanks for the advice! Link to comment Share on other sites More sharing options...
mfg Posted March 27, 2016 Report Share Posted March 27, 2016 You're lucky that the Computer Command Control system is still working well on your '83!...After struggling with the same system on my own '83 Avanti 'everyday driver', I carefully removed and stored the ecm, electronic Rochester carb, and computer controlled distributor and replaced those items with 'pre-computer replacements. Frankly, the car runs great, and I've never looked back! Link to comment Share on other sites More sharing options...
mfg Posted March 28, 2016 Report Share Posted March 28, 2016 (edited) arkus....Just to give you an idea, I purchased a non-electronic Rochester Quadra-jet carb and a non-computer controlled HEI distributor (with the vacuum advance canister), originally made for a '78-'79 Chevy Impala with a 350 CI V8. Edited March 28, 2016 by mfg Link to comment Share on other sites More sharing options...
A83 Posted March 29, 2016 Report Share Posted March 29, 2016 My 83 came with a new 350 engine and the computer hanging by straps under the dash. Silly. A company I used mounted it on a wooden board under the carpet on the passenger where your feet angle up when sitting. The carpet and the computer fold down when you need it and you don't even know it's there. They also disconnected the check engine light a n d the car runs great. Kevin Link to comment Share on other sites More sharing options...
Avanti83 Posted March 29, 2016 Report Share Posted March 29, 2016 My 83 came with a new 350 engine and the computer hanging by straps under the dash. Silly. A company I used mounted it on a wooden board under the carpet on the passenger where your feet angle up when sitting. The carpet and the computer fold down when you need it and you don't even know it's there. They also disconnected the check engine light a n d the car runs great. Kevin Are you still using the computer or is the engine back to a conventional carb and dissy? I'm curious as I replaced my SBC in the 83 and stripped out the computer harness. It now runs a Holley EFI setup. Other than a couple of power wires, the computer harness is a separate add on. Not suggesting you pull yours but just FYI. Bob Link to comment Share on other sites More sharing options...
wildfelr Posted March 29, 2016 Report Share Posted March 29, 2016 RQB 3263....About a year ago I de-computerized my 81/305 exactly as described above...and highly recommend it....the replacement carb was about 170.00$.direct bolt on one wire hookup,,, and the HEI Vacuum distributor was $70...follow each of the wires back to there source and remove them and there associated box...I think mine all went in the trash...I also removed all the pollution control crap (about 50 lbs)< new mufflers and Add a Crane torque cam/lifter/valve spring set and double roller Cloyes timing chain set available anywhere for $25 and it will run like a new engine ...its easy to do ....good luck....bill rqb3263 Link to comment Share on other sites More sharing options...
sat65 Posted March 29, 2016 Report Share Posted March 29, 2016 (edited) Do you have specific part numbers for the carb and HEI that you used? I should do this to my 84 305. Edited March 29, 2016 by sat65 Link to comment Share on other sites More sharing options...
wildfelr Posted March 30, 2016 Report Share Posted March 30, 2016 RQB3263...hOPE THIS HELPS...National carburetor..."King of Carburetors"...4 bbl is $159.95 with exchange....mine required one adjustment after install which we did over the phone just fine...904-636-9400....they also supplied the distributor for about $70...it all works great ....good luck ...RQB3263 Link to comment Share on other sites More sharing options...
wildfelr Posted March 30, 2016 Report Share Posted March 30, 2016 RQB3263...You are aware that the 305 engines from factory had "soft" camshafts and lifters and plastic (actually nylon) timing gear......mine was A typical BAD...I had been warned here on the forum....I had 4 warnout lobes and 3 concave lifters...at 95k miles...I used Crane Cam because there close to me here in Fl. but there are a gillion SBC can mfg...RQB3263....BILL Link to comment Share on other sites More sharing options...
A83 Posted March 31, 2016 Report Share Posted March 31, 2016 Are you still using the computer or is the engine back to a conventional carb and dissy? I'm curious as I replaced my SBC in the 83 and stripped out the computer harness. It now runs a Holley EFI setup. Other than a couple of power wires, the computer harness is a separate add on. Not suggesting you pull yours but just FYI. Bob My engine is fuel injected and not sure if the computer is working or not. Sorry not that sophisticated. The people who did the work moving it didn't seem to think it was worth much and really neither do I. They said have the hook up for the check light was not needed as these cars do not go thru emission testing and it could actually run better without it so I let them do it. I don't have the light in the dash anymore. I had black anodized aluminum inserts put in and did not have them drill the hole for it. Sorry can't be more help. Kevin Link to comment Share on other sites More sharing options...
Avanti83 Posted March 31, 2016 Report Share Posted March 31, 2016 My engine is fuel injected and not sure if the computer is working or not. Sorry not that sophisticated. The people who did the work moving it didn't seem to think it was worth much and really neither do I. They said have the hook up for the check light was not needed as these cars do not go thru emission testing and it could actually run better without it so I let them do it. I don't have the light in the dash anymore. I had black anodized aluminum inserts put in and did not have them drill the hole for it. Sorry can't be more help. Kevin If it's fuel injected then that's not the original computer. The original was a controlled?? carb. I'll agree on the worth of the original setup but because the new setup runs well the rest is moot. I'd be curious how the engine light would effect performance but again a moot point as long as you are happy with the setup. Avanti, Bob Link to comment Share on other sites More sharing options...
A83 Posted April 1, 2016 Report Share Posted April 1, 2016 I think they did something with the catalytic converter? Link to comment Share on other sites More sharing options...
GarageHawk Posted January 12, 2017 Report Share Posted January 12, 2017 On 3/31/2016 at 1:51 PM, A83 said: My engine is fuel injected and not sure if the computer is working or not. Sorry not that sophisticated. The people who did the work moving it didn't seem to think it was worth much and really neither do I. They said have the hook up for the check light was not needed as these cars do not go thru emission testing and it could actually run better without it so I let them do it. I don't have the light in the dash anymore. I had black anodized aluminum inserts put in and did not have them drill the hole for it. Sorry can't be more help. Kevin Kevin, You wouldn't happen to still have your original check engine light? Actually, all I need is the plastic lens. Mine is cracked. Thanks, Bill Link to comment Share on other sites More sharing options...
A83 Posted February 4, 2017 Report Share Posted February 4, 2017 I don't think I have it but I will check today to see if I put it in the glove compartment Link to comment Share on other sites More sharing options...
A83 Posted February 5, 2017 Report Share Posted February 5, 2017 Sorry Bill I can't find it Kevin Link to comment Share on other sites More sharing options...
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