Honda Car Forum

Did the carbureted engine, say, for Civic or CRX from early 80s to early 90s
have any sort of ECU or its alternative (control box)???

For some reason I convinced myself that only vehicle with fuel injection
(read: it has fuel injectors, not carburetor) will and can have ECU.

Tell me that I am wrong. What specifically can ECU do on carbureted engine
if everything is manual or vacuum driven, as far as fuel mixture, and ECU
has no way to adjust it?

TNX

My old 1981 Camaro Z-28 had an ECU and a carb. The carb was basically a
modified 4 barrel Quadrajet. If I recall, as Im going back to my high-school
days here...the ECU controlled the accelerator pump on the carb. The car
also has a MAP (manifold pressure sensor) and an 02 sensor. On-board
diagnostics were part ofthe ECU as well. 1981 was the first year GM put ECUs
on board.


"Dimmi" <eranospamser@new.rr.com> wrote in message
news:mNIgb.16034$%C5.15179@twister.rdc-kc.rr.com...
> Did the carbureted engine, say, for Civic or CRX from early 80s to early
90s
> have any sort of ECU or its alternative (control box)???
>
> For some reason I convinced myself that only vehicle with fuel injection
> (read: it has fuel injectors, not carburetor) will and can have ECU.
>
> Tell me that I am wrong. What specifically can ECU do on carbureted engine
> if everything is manual or vacuum driven, as far as fuel mixture, and ECU
> has no way to adjust it?
>
> TNX
>
>

Now, please, try to recall WHAT would that ECU do to the accel pump to
change, say, fuel mixture, HOW would it interpret data from MAP and O2
sensor, what would it do with all the "data". I mean, what were the
mechanics involved? Did the ECU "alter" the engine management through vacuum
lines, solenoids, electric motors, cables?

With MPFI it is easy - a matter of simply sending a signal, change in the
voltage, whatever.
Really interesting!

"RkFast" <RkFast@nospam.net> wrote in message
news:_1Kgb.67922$E95.34455926@news4.srv.hcvlny.cv. net...
> My old 1981 Camaro Z-28 had an ECU and a carb. The carb was basically a
> modified 4 barrel Quadrajet. If I recall, as Im going back to my
high-school
> days here...the ECU controlled the accelerator pump on the carb. The car
> also has a MAP (manifold pressure sensor) and an 02 sensor. On-board
> diagnostics were part ofthe ECU as well. 1981 was the first year GM put
ECUs
> on board.
>
>
> "Dimmi" <eranospamser@new.rr.com> wrote in message
> news:mNIgb.16034$%C5.15179@twister.rdc-kc.rr.com...
> > Did the carbureted engine, say, for Civic or CRX from early 80s to early
> 90s
> > have any sort of ECU or its alternative (control box)???
> >
> > For some reason I convinced myself that only vehicle with fuel injection
> > (read: it has fuel injectors, not carburetor) will and can have ECU.
> >
> > Tell me that I am wrong. What specifically can ECU do on carbureted
engine
> > if everything is manual or vacuum driven, as far as fuel mixture, and
ECU
> > has no way to adjust it?
> >
> > TNX
> >
> >
>
>
>

Lots of cars with carburetors used ECUs in the late 70's and early 80's.
These were often refereed to as "feedback carburetors" and doing a
google search will give you a lot of hits (mostly useless ones, though).

I know some used a stepper motor to control an auxiliary air valve that
led extra air in after the venturi.


dimmi wrote:
>
> Now, please, try to recall WHAT would that ECU do to the accel pump to
> change, say, fuel mixture, HOW would it interpret data from MAP and O2
> sensor, what would it do with all the "data". I mean, what were the
> mechanics involved? Did the ECU "alter" the engine management through vacuum
> lines, solenoids, electric motors, cables?
>
> With MPFI it is easy - a matter of simply sending a signal, change in the
> voltage, whatever.
> Really interesting!
>
> "RkFast" <RkFast@nospam.net> wrote in message
> news:_1Kgb.67922$E95.34455926@news4.srv.hcvlny.cv. net...
> > My old 1981 Camaro Z-28 had an ECU and a carb. The carb was basically a
> > modified 4 barrel Quadrajet. If I recall, as Im going back to my
> high-school
> > days here...the ECU controlled the accelerator pump on the carb. The car
> > also has a MAP (manifold pressure sensor) and an 02 sensor. On-board
> > diagnostics were part ofthe ECU as well. 1981 was the first year GM put
> ECUs
> > on board.
> >
> >
> > "Dimmi" <eranospamser@new.rr.com> wrote in message
> > news:mNIgb.16034$%C5.15179@twister.rdc-kc.rr.com...
> > > Did the carbureted engine, say, for Civic or CRX from early 80s to early
> > 90s
> > > have any sort of ECU or its alternative (control box)???
> > >
> > > For some reason I convinced myself that only vehicle with fuel injection
> > > (read: it has fuel injectors, not carburetor) will and can have ECU.
> > >
> > > Tell me that I am wrong. What specifically can ECU do on carbureted
> engine
> > > if everything is manual or vacuum driven, as far as fuel mixture, and
> ECU
> > > has no way to adjust it?
> > >
> > > TNX
> > >
> > >
> >
> >
> >

"Dimmi" <eranospamser@new.rr.com> wrote in message
news:mNIgb.16034$%C5.15179@twister.rdc-kc.rr.com...
> Did the carbureted engine, say, for Civic or CRX from early 80s to early
90s
> have any sort of ECU or its alternative (control box)???
>
> For some reason I convinced myself that only vehicle with fuel injection
> (read: it has fuel injectors, not carburetor) will and can have ECU.

My '85 Escort (carburated of course) had something that the mechanic
referred to as "brain box". I suspect that's what they called an ECU back
then. Unfortunately, I don't know exactly what its function was, but it did
break once and had to be replaced.

Cheers,

Pete

Carburetor is called Emission Control Unit not ECU. Fuel injection is
called ECU or Electronic Control Unit to avoid confusion.

The Emission Control Unit controls vacuum flow by blocking or
unblocking solenoids. For instance, it could cut-off fuel under
deceleration. It has a variety of jobs.

> Now, please, try to recall WHAT would that ECU do to the accel pump to
> change, say, fuel mixture, HOW would it interpret data from MAP and O2
> sensor, what would it do with all the "data".

Voltages from O2 are converted to digital at which it activates a
preprogrammed instruction. The instructions triggers a transistor to
open the mixture solenoid valve to increase air ratio only if O2 says
0.9V or higher, for example.

> I mean, what were the
> mechanics involved? Did the ECU "alter" the engine management through vacuum
> lines, solenoids, electric motors, cables?

No cables, or motors as I recall.


> With MPFI it is easy - a matter of simply sending a signal, change in the
> voltage, whatever. Really interesting!

Koji

> > My old 1981 Camaro Z-28 had an ECU and a carb. The carb was basically a
> > modified 4 barrel Quadrajet. If I recall, as Im going back to my
> high-school
> > days here...the ECU controlled the accelerator pump on the carb. The car
> > also has a MAP (manifold pressure sensor) and an 02 sensor. On-board
> > diagnostics were part ofthe ECU as well. 1981 was the first year GM put
> ECUs
> > on board.
> >
> >
> > "Dimmi" <eranospamser@new.rr.com> wrote in message
> > news:mNIgb.16034$%C5.15179@twister.rdc-kc.rr.com...
> > > Did the carbureted engine, say, for Civic or CRX from early 80s to early
> 90s
> > > have any sort of ECU or its alternative (control box)???
> > >
> > > For some reason I convinced myself that only vehicle with fuel injection
> > > (read: it has fuel injectors, not carburetor) will and can have ECU.
> > >
> > > Tell me that I am wrong. What specifically can ECU do on carbureted
> engine
> > > if everything is manual or vacuum driven, as far as fuel mixture, and
> ECU
> > > has no way to adjust it?
> > >
> > > TNX
> > >
> > >
> >
> >
> >

OK...now youre pushing it.... :-)

I think, basically, you got it right. The ECU used data from the MAP and O2
sensor to adjust the fuel mixture through the accelerator pump. It was
pretty rudimentary.

"dimmi" <someone@new.rr.com> wrote in message
news:vnKgb.16109$%C5.13952@twister.rdc-kc.rr.com...
> Now, please, try to recall WHAT would that ECU do to the accel pump to
> change, say, fuel mixture, HOW would it interpret data from MAP and O2
> sensor, what would it do with all the "data". I mean, what were the
> mechanics involved? Did the ECU "alter" the engine management through
vacuum
> lines, solenoids, electric motors, cables?
>
> With MPFI it is easy - a matter of simply sending a signal, change in the
> voltage, whatever.
> Really interesting!
>
> "RkFast" <RkFast@nospam.net> wrote in message
> news:_1Kgb.67922$E95.34455926@news4.srv.hcvlny.cv. net...
> > My old 1981 Camaro Z-28 had an ECU and a carb. The carb was basically a
> > modified 4 barrel Quadrajet. If I recall, as Im going back to my
> high-school
> > days here...the ECU controlled the accelerator pump on the carb. The car
> > also has a MAP (manifold pressure sensor) and an 02 sensor. On-board
> > diagnostics were part ofthe ECU as well. 1981 was the first year GM put
> ECUs
> > on board.
> >
> >
> > "Dimmi" <eranospamser@new.rr.com> wrote in message
> > news:mNIgb.16034$%C5.15179@twister.rdc-kc.rr.com...
> > > Did the carbureted engine, say, for Civic or CRX from early 80s to
early
> > 90s
> > > have any sort of ECU or its alternative (control box)???
> > >
> > > For some reason I convinced myself that only vehicle with fuel
injection
> > > (read: it has fuel injectors, not carburetor) will and can have ECU.
> > >
> > > Tell me that I am wrong. What specifically can ECU do on carbureted
> engine
> > > if everything is manual or vacuum driven, as far as fuel mixture, and
> ECU
> > > has no way to adjust it?
> > >
> > > TNX
> > >
> > >
> >
> >
> >
>
>

Correction, it should read. The Emission Control Unit controls vacuum
flow by blocking or unblocking flow using solenoids.

> The Emission Control Unit controls vacuum flow by blocking or
> unblocking solenoids. For instance, it could cut-off fuel under
> deceleration. It has a variety of jobs.

I have a 1987 Accord DX (Carb, Sedan, US model)
I know with a fuel injected car, while decelerating, the injectors are
typically shut off to increase fuel economy.
So, on my carb model, does the fuel get cut off during decel? Or would
shifting to neutral during deceleration be better for fuel economy?


"Koji San" <apple26pie@yahoo.com> wrote in message
news:fa1ef2c1.0310080346.1203c27f@posting.google.c om...
> Carburetor is called Emission Control Unit not ECU. Fuel injection is
> called ECU or Electronic Control Unit to avoid confusion.
>
> The Emission Control Unit controls vacuum flow by blocking or
> unblocking solenoids. For instance, it could cut-off fuel under

>[Would fuel cut off during deceleration & in gear on Carb?]

Yes. I'd been waiting for someone to ask this question. Shifting to
nuetral will not save gas as fuel is used for idling. On the the DX,
fuel will shut off during decelerating while in gear and over 1200
rpm. Hint: Cruising at 30-40mph on 5ft gear will use almost about the
same gas as idling, (as surveyed on my test jig).
K

> I have a 1987 Accord DX (Carb, Sedan, US model)
> I know with a fuel injected car, while decelerating, the injectors are
> typically shut off to increase fuel economy.
> So, on my carb model, does the fuel get cut off during decel? Or would
> shifting to neutral during deceleration be better for fuel economy?
>
>
> "Koji San" <apple26pie@yahoo.com> wrote in message
> news:fa1ef2c1.0310080346.1203c27f@posting.google.c om...
> > Carburetor is called Emission Control Unit not ECU. Fuel injection is
> > called ECU or Electronic Control Unit to avoid confusion.
> >
> > The Emission Control Unit controls vacuum flow by blocking or
> > unblocking solenoids. For instance, it could cut-off fuel under