Does ECM = MCU ? - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 02-14-2002, 11:13 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Does ECM = MCU ?

I am trying to understand the lingo of some postings and have been confused by the postings vs. text manuals. Is the ECM the Emission Control Unit ? If so , how does it function ? Is the MCU the brain micro processing unit of the computer controlled carburetor feedback systems ? Are these the same or differnet ? Where to locate each in the YJ ?

Sponsored Links
Advertisement
 
post #2 of (permalink) Old 02-14-2002, 12:32 PM
 
Join Date: Jun 2001
Posts: 1,705
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Does ECM = MCU ?

A horse is still a horse...

I call them the "computer". ECM, PCM, MCU - AFAIK they're the same. Not sure about YJs, but emissions-controlled CJ "computers" are located behind the glove box.

I'm boycotting sigs. If ya wanna see what I have, check my profile.
AllLockedUp is offline  
post #3 of (permalink) Old 02-14-2002, 03:07 PM
Enthusiast
 
Join Date: Jan 2002
Location: Virginia
Posts: 236
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: Does ECM = MCU ?

I'm not familiar with "emissions control unit." I think the answer to your question is yes, MCU and ECM are the same. I think ECM stands for engine control management or something close to that.

TEXAS1AL

84 CJ-7; 258 I6; Restored-to-Stock Condition, TR Ignition Upgrade
texas1al is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 02-14-2002, 03:33 PM
Official Curmudgeon
 
CJ7Taz's Avatar
 
Join Date: Nov 2001
Location: Kansas
Posts: 4,706
Thanks: 2
Thanked 5 Times in 5 Posts
 
Re: Does ECM = MCU ?

ECM = Electronic Control Module, the brain.


I've replaced so many parts that my old Jeep has become my new Jeep.
CJ7Taz is offline  
post #5 of (permalink) Old 02-14-2002, 03:58 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Does ECM = MCU ?

Taz is correct re: ECM. However, depending on your year jeep, you are going to have more than 1 module. On pre-FI jeeps with the computer controlled carb, you will have the ECM (commonly called the "Computer") that is mounted under the dash (typically on top of the heater duct) and it controls the Carb servo and the other emissions control, i.e., PCV solenoid, etc. Then located on the left fender well is the ignition control module (ICM). This is the standard Motocraft control module for the Duraspark system. Except for one wire, it can run the jeep without the ECM. The one wire is the feed for the coil. The ECM intercepts the signal and delays as necessary to compensate for inputs from the other sensors. The Nutter Bypass is a way of bypassing the computer. I personally don't know if it gains you anything over a properly running setup.

On later fuel injected engines, there is only the ECM or computer which takes all the inputs from sensors and drives the ignition and injectors.

Maybe we should get them to include a glossary for this BBS. Some acronyms have two or three meanings depending on context..i.e., R&P...is it Ring and Pinion, Rack and Pinion or Red and Pink?

John...
84CJ7, 3"lift, 32"BFG, 4.10's, R/ARB, F/Detroit, Onboard Air....89 Cherokee - New Project

They say we learn by our mistakes.....I guess thats why we are all so smart.
post #6 of (permalink) Old 02-15-2002, 06:54 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Does ECM = MCU ?

Thanks to all who contributed to my education and clarity of the subject. I wish that I had had this understanding long ago . It would have saved me much slow learning.

Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups 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










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not 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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On

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