1996 Transmission swap help!!! - Miata Forumz - Mazda Miata Chat Forums

NA (1989-1997) NA Miata discussion within. The MX5's first generation, the NA, sold over 400,000 units from 1989 to 1997.

1996 Transmission swap help!!!

Old 11-04-2013, 07:06 PM
  #1  
!!!! I NEED TO POST !!!!
Thread Starter
 
Join Date: Nov 2013
Location: South Jordan, UT
Posts: 3
Default 1996 Transmission swap help!!!

I recently swapped out my 1996 Auto trans. For a 5 Speed out of a 1995 with a blown Motor. I had the motor rebuilt at the same time as well as all the seals in the manual at that time. I installed an ECU from a 1997. I removed the Auto trans computer as well. Now, I have a check engine light that won't go out and it says that I have an ECU - TCU communication error? (I didn't change the wiring harness) I'm not sure what else needs to be connected? If someone can send me in the right direction, it would be great! Thanks in advance.
Miataali is offline  
Old 11-05-2013, 02:12 AM
  #2  
MFz Regular
 
CharlesE's Avatar
 
Join Date: Oct 2013
Location: North Stonington, Connecticut
Posts: 107
Default

The ECU and ALL of the other sensors need to talk to each other. Is the new ECU from an automatic car?

The TCU is the Transmission Control Unit, used only on automatic cars.

Look at the Wikipedia link Transmission control unit - Wikipedia, the free encyclopedia for a starting point.

You have a 1996 automatic transmission wiring harness, a 1995 manual transmission. and a 1997 ECU. With all of the emissions changes (different sensors, different programming) that have happened over those years, you may have an interesting task ahead of you. You know that, right!

Consider discussing this with a Miata specialist mechanic. I doubt any of the Mazda publications (Workshop Manuals will help directly.). You could start by comparing part numbers from the various year Manuals. I suspect the parts all need to be capable of talking to each other.

If you don't have a shop nearby, a call to Flyin Miata may provide some guidance.

Do you need to pass an electronic (OBDI or OBDII) emissions in your area, in other words is the check engine light a concern or simply an annoyance?
CharlesE is offline  
Old 11-05-2013, 06:51 AM
  #3  
!!!! I NEED TO POST !!!!
Thread Starter
 
Join Date: Nov 2013
Location: South Jordan, UT
Posts: 3
Default

Hey Charles, the ECU is from a 5 Speed. I was under the impression that the 96 & 97 were identical in electronics. My biggest question really is how does an ECU from a 5 speed know the the transmission communication isn't right when the TCU isn't even there? I'm fairly certain that I'm just needing to make a connection between a few wires but not sure which ones? As for the check engine light, it is part of the registration process here in Utah. So I'm pretty much dead in the water.
Thanks Ali
Miataali is offline  
Old 11-05-2013, 08:29 AM
  #4  
Moderator
 
sixshooter's Avatar
 
Join Date: Jul 2011
Location: Tampa, FL; Lake Jackson (Atlanta), GA
Posts: 1,901
Default

We have all of the wiring diagrams right here on the forum.

I'm not sure why you are seeing the code. Yes, '96 and '97 were the same. I can't tell you functionally if it will make an operational difference or not. It may cause the computer to remain open loop during driving.

Study the diagrams for clues as to why.
sixshooter is offline  
Old 11-05-2013, 05:40 PM
  #5  
MFz Regular
 
CharlesE's Avatar
 
Join Date: Oct 2013
Location: North Stonington, Connecticut
Posts: 107
Default

As I understand it, you still have the 1996 auto trans wiring harness. Check to see if there are any connectors that go to the auto transmission. if so, it is likely that the ecu expects to see a resistance from those connectors, or possibly a voltage, either of which you may need to supply. As sixshooter suggests, compare the two wiring harnesses....perhaps a connector can simply be deleted.
CharlesE is offline  
Old 11-05-2013, 06:50 PM
  #6  
!!!! I NEED TO POST !!!!
Thread Starter
 
Join Date: Nov 2013
Location: South Jordan, UT
Posts: 3
Default

Ok. I'll try to look at the diagram and track down which wires are different. Thanks for the info. 😊
Miataali is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
sixshooter
How To...
10
04-25-2017 12:22 PM
Ron Reefman
Drivetrain
1
04-27-2014 09:44 AM
mytwo
Drivetrain
10
09-04-2012 09:19 AM
Redcap
Interior and Exterior
8
10-27-2011 11:09 PM
jared8783
NA (1989-1997)
2
08-07-2011 01:10 PM


Thread Tools
Search this Thread
Quick Reply: 1996 Transmission swap help!!!


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.