Basic EFI Needs? - Ford Muscle Forums : Ford Muscle Cars Tech Forum
 
LinkBack Thread Tools
post #1 of 7 (permalink) Old 10-15-2002, 05:32 AM Thread Starter
Registered User
 
Join Date: Mar 2002
Location: Los Angeles
Posts: 904
Basic EFI Needs?

I was wondering what is the basic information that a computer needs form an engine to flow a proper amount of fuel at any giver time? Im thinking its just Air Flow and RPM's. Anything I left out? Oh, by the way, what "mechanical" info does a Carb use to meter fuel?
Thanks,

Thanks,
Kenny
1999 SVT Cobra
1996 3.8L Coupe
1968 289 Coupe
HitmanKB is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 10-15-2002, 07:36 AM
Subscriber
 
Join Date: Aug 2001
Posts: 189
Basic EFI Needs?

Well, i think that the most basic info an EFI needs is RPM and Airflow/AirPressure ...

then they usualy mesure the outside air pressure to compensate for altitude changes
and air Temp, to compensate for that.
and water Temp .. to add more fuel until the engine is hot enugh
zICRONIx is offline  
post #3 of 7 (permalink) Old 10-15-2002, 11:55 AM
Registered User
 
Join Date: Apr 2002
Posts: 430
Basic EFI Needs?

Alpha/N operation is Throttle Position, which is the least info you can get away with for EFI, but you might as well run a carb.

The most common sensors are Manifold Absolute Pressure/Manifold Air Density, Coolant Temp, Air Intake Temp, Exhaust O2 and Throttle Position.


Jeremy Wilson
1969 Ford Torino GT Fastback
351W 4-speed
NasalGoat is offline  
 
post #4 of 7 (permalink) Old 10-15-2002, 02:01 PM Thread Starter
Registered User
 
Join Date: Mar 2002
Location: Los Angeles
Posts: 904
Basic EFI Needs?

Ok now I have a few more questions. Whats the difference between Speed Density and Mass Air EFI setups? What does the O2 sensor used for and is it necessary?
Thanks,

Thanks,
Kenny
1999 SVT Cobra
1996 3.8L Coupe
1968 289 Coupe
HitmanKB is offline  
post #5 of 7 (permalink) Old 10-16-2002, 03:47 AM
Subscriber
 
Join Date: Aug 2001
Posts: 189
Basic EFI Needs?

The O2 sensor can be used in a closed loop system, so that the EFI can adjust it self to get the right amount of fuel .. but you can run without it too..

zICRONIx is offline  
post #6 of 7 (permalink) Old 10-17-2002, 05:19 PM
Registered User
 
Join Date: Apr 2002
Posts: 430
Basic EFI Needs?

Speed Density is a system whereby manifold vacuum and air temp is measured to determine total airflow into the engine.

Mass Air uses a heated wire to determine the actual amount of airflow into the engine.

Common magazine groupthink on the subject is that "SD bad, MA good" based on the fact that MA allows you to make modifications to your engine without having to recalibrate your controller - it will adjust automatically to the increased airflow to a certain point. This is fine if you're modifying a stock engine slightly. Anything more and you have to recalibrate.

Mass Air is more complex than Speed Density in terms of the sensors required, plus the restrictions on airflow it has. If you're going to be playing with the VE tables in the computer anyway, SD is the simpler way to go in terms of setup and maintenance.


Jeremy Wilson
1969 Ford Torino GT Fastback
351W 4-speed
NasalGoat is offline  
post #7 of 7 (permalink) Old 10-17-2002, 05:20 PM
Registered User
 
Join Date: Apr 2002
Posts: 430
Basic EFI Needs?

Oh, the O2 sensor is used to adjust the A:F ratio during engine operation, or can be used for initial tuning. It's recommended but not needed.

Jeremy Wilson
1969 Ford Torino GT Fastback
351W 4-speed
NasalGoat is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Muscle Forums : Ford Muscle Cars Tech Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome