ECM ‘s job ?
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 3
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From: Onalaska Wi
Car: 1984 Z28
Engine: 305 Crossfire
Transmission: Automatic
ECM ‘s job ?
What does the ECM control ? I have a 1986 IROC-Z 5-spd 305 carbureted all factory I would like to get rid of the Quadrajet and put on a Holley 600. Also replace the distributor with a new HEI. What are your thoughts?
Supreme Member
Joined: Dec 2012
Posts: 1,356
Likes: 15
From: northern VA
Car: 88 Sport Coupe Camaro
Engine: V6 2.8
Transmission: Borg-Warner T-5
Axle/Gears: RPO/GU6: 3.42
Re: ECM ‘s job ?
If you are running a factory carb with factory ECM, the ECM is reading the voltage from the O2 sensor. The ECM then signals the solenoid on the carb to deliver more fuel or less fuel via a needle valve on the carb.
If you remove your factory carb, you dumb-down your fuel delivery system.
If you remove your factory carb, you dumb-down your fuel delivery system.
Joined: Mar 2014
Posts: 4,553
Likes: 806
From: South Ms
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: ECM ‘s job ?
On a stock-ish car the quadrajet is hard to beat. It does a great job i wouldn't touch it. If it gave me problems id get another just like it. I swapped one out for an eddy intake and Holley 650DP years ago and while it did help performance a bit...it really hurt my mileage and then it had to be tuned every time I turned around.
Supreme Member
Joined: Dec 2012
Posts: 1,356
Likes: 15
From: northern VA
Car: 88 Sport Coupe Camaro
Engine: V6 2.8
Transmission: Borg-Warner T-5
Axle/Gears: RPO/GU6: 3.42
Re: ECM ‘s job ?
Everything you ever wanted to know about servicing a computer-controlled Quadra-Jet carb:
https://docs.google.com/file/d/1kKj0...iletype=msword
MS-Word formatted document on my Google Drive cloud directory.
https://docs.google.com/file/d/1kKj0...iletype=msword
MS-Word formatted document on my Google Drive cloud directory.
Re: ECM ‘s job ?
The easy compromise is to get a non-CCC Qjet from a slightly earlier GM car and a vacuum advance HEI. That way you still have a carb that bolts up to everything correctly, and clears the hood, while also getting rid of the computer controls.
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