1981 carburetor
Thread Starter
Racer
Joined: Apr 2008
Posts: 333
Likes: 0
From: Portage Michigan
1981 carburetor
So I have been told that my '81 has the wrong carburetor, but not why or how they knew (long story). My neighbor and I have looked the thing over, even removed it, and by all accounts, we can't tell why it is the wrong one (he is a mechanic, I am not). My understanding is that the computer system on the car controls the carburetor. So it dawned on me the other night, if the computer does control the carb, then the computer needs to be linked to it somehow. My question is how is this done. My theory is that there is an electrical plug that plugs into the carb, and if I have a carb that even though it technically fits, (it is not connected to anything via electrical plug because I unplugged and there was no such thing when removing it) that makes it the wrong carb. I also am thinking that this is what has caused the engine light to come on and that is what told the mechanic it was the wrong carb. The car does run, I've been driving it all summer the way it is, it just has a low idle speed. I realize I could take it back to my mechanic, but why pay $80/hour when I can bounce ideas off of your head for free 
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
I'm no expert on the topic, but I believe that the '81 Q-jet had some components in it that were controlled [electrically] by the computer. There was one electrical connector on the front of the carb. And, as I recall, it was a one-off part that was only produced for that year. If yours does NOT have that feature, you may have to search auto 'bone yards' for the correct unit and then have it rebuilt (or rebuild it yourself). The GM Service Manual for the '81 Corvette should have pretty detailed info on how to check out that carb. Also, there is no reason why another Q-jet wouldn't work OK on your car. It wouldn't be computer controlled, but it should operate as well as any other non-computer controlled Q-jet car. You may have to research how the HEI distributor functions in connection with the electronic carb to decide what changes are required, if you decide to stay with the non-electronic carb.
Instructor
Joined: Apr 2006
Posts: 232
Likes: 0
From: Henrietta New York
I have an 81. Previous posts are correct. The 81 carb has an electrical connection at the front. I have not gotten to the engine/carb portion yet for my resto but I am guessing the car would run less than optimal if you are using a non 81 carb with the factory computer and distributor. At some point I will learn this aspect of the resto.
Racer
Joined: Mar 2008
Posts: 428
Likes: 0
Going from memory, which is scary, I believe the electronic carb started in 1980 with california and the rest in 1981. It has a mixture control soleniod in the float bowl area, a throttle position sensor and I believe an idle speed connector. All were controlled by the computer control. Who every replace the original electonic unit probably thought it was easier than fixing the original. I don't remember how or if the HEI was tied to the computer. maybe somebody else can.
Race Director
Joined: Oct 2000
Posts: 12,639
Likes: 3,101
From: Shamong, NJ
The Q-jet Carb numbers for 1981 are: 17081217 with a 4 speed, 17081228 with an automatic and 17081218 for Calif. cars. This number can be found as a stamping on a boss on the drivers side rear of the main body of the carb. The numbers run vertically and include a 2 digit plant code and a julian date (001-031 would be a Jan. carb, 032-059 is Feb. etc.). As stated in other posts, the carb has an electrical terminal to connect it to the computor.
Drifting
Joined: Apr 2006
Posts: 1,911
Likes: 2
From: gold coast queensland
81 computer had input into the carb, distributor and transmission. by disconnecting the correct qjet the computer will be sending incorrect readings to the dizzy. there is a good chance if your carb has been changed then so has your distributor. is it the standard one? its not hard to remove the computer from your 81 if you want to upgrade to a different carb and distributor. sure you can keep the same transmission and use a switch to take advantage of the loc-up but be warned if you want to change to a different converter in the TH350C you cant just throw in a tci or b&m for example, they will not fit.
Burning Brakes
Joined: Oct 2009
Posts: 838
Likes: 2
From: Baton Rouge Louisiana
If it offers any help to you, here is my carb on my 81, I took the photo a while back to remember the vertical numbers. It has only one plug in on the front passenger side that controls the fuel air mixture.
Last edited by golfradict; Jan 18, 2014 at 11:47 AM.
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Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
This posting is from 6 years ago; doubt the original poster is still looking for an answer.
But for what it is worth; the E4ME carb has three electrical connections:
1) Mixture Control Solenoid
2) Throttle Position Sensor
3) Electric Choke
But for what it is worth; the E4ME carb has three electrical connections:
1) Mixture Control Solenoid
2) Throttle Position Sensor
3) Electric Choke
Burning Brakes
Joined: Oct 2009
Posts: 838
Likes: 2
From: Baton Rouge Louisiana
