2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

CAS reads .126 ohms

Thread Tools
 
Search this Thread
 
Old 09-09-23, 02:33 PM
  #1  
Junior Member

Thread Starter
 
cdoublejj's Avatar
 
Join Date: Oct 2013
Location: USA, MO
Posts: 6
Received 0 Likes on 0 Posts
CAS reads .126 ohms

So Mitchell 1 is saying that Ne and G sensors should read 110-220 ohms each. does this sound correct?


This is on an 88 non turbo, crank no start, ridden hard and put away dirty for some years it looks.

Any how the coil pack behind the headlight has fire but, the one at the firewall has not fire. the wiring harness plugs for the wire wall coil have have 5 volts i assume reference or ecu witch tracks wit the wiring diagram and 1x 12v lead and 1lead with no voltage and is also NOT ground, this plug has 4 pins and looks to go to ecu. the other plug is putting 12v on both pins and go to ..well i didn't follow that one since it's putting out 12v on both pins.

i thought i'd start here since i am not getting 110-220 ohms but, odd bit is fire off the coil behind the drivers side headlight. i'm not seeing many mouse turds or chewed wires. things fine inside of the CAS with the lid off.
Old 09-11-23, 06:23 PM
  #2  
Full Member
 
Jeff76's Avatar
 
Join Date: Jul 2023
Location: Pittsburgh
Posts: 115
Received 38 Likes on 33 Posts
110-120 Ohms is correct from the FSM. It helps to know search terms. The coil near the firewall is the trailing coil.

Crank no start dead trailing coil: Trailing Coil Search This should keep you busy for a while.
Old 09-12-23, 11:59 AM
  #3  
Junior Member

Thread Starter
 
cdoublejj's Avatar
 
Join Date: Oct 2013
Location: USA, MO
Posts: 6
Received 0 Likes on 0 Posts
i've noticed that if i wish to confirm a bad CAS that a replacement appears to be $300 to $400 USD. or is there some after market piece i'm not aware of. also i will start going down that rabbit hole as well.
Old 09-12-23, 07:17 PM
  #4  
Full Member
 
Jeff76's Avatar
 
Join Date: Jul 2023
Location: Pittsburgh
Posts: 115
Received 38 Likes on 33 Posts
That is a good question. I think many have survived on the generosity of forum members. I have seen extras being sold on here for reasonable prices. There is a chance that the connections are bad at the connector or other easy to fix reasons.

First, verify the orientataoin of the connector is correct. So you won't be ohming he wrong wires.
Two, the pins or connector could be bad. I would find where the wires are teminated in the CAS and ohm from there, if possible. You might be able to hardwire or other to bypass the possible bad or dirty pins. Try contact cleaner first on both connectors and/or other ways to clean contacts. Also Ohm out the length of the wire from inside the CAS to the connector if possible.
Three, if all the above fails or isn't worth your time replace the CAS.
Four, give up and sell the car to a forum member.

Maybe others could shed some light on this. I did post a search, the answer could be there. At least you will verify if a bad CAS will cause the trailing not to fire, which I think it does. If I am remembering correctly there are a few other things that could cause it as well, like a bad coil or improper coil grounding. ohming out the coil is a good way to know, not the best but is at least mostly relaible, I beleive.

Last edited by Jeff76; 09-12-23 at 07:22 PM.
Old 09-13-23, 09:43 AM
  #5  
Junior Member

Thread Starter
 
cdoublejj's Avatar
 
Join Date: Oct 2013
Location: USA, MO
Posts: 6
Received 0 Likes on 0 Posts
your link actually brings up zero search results when i click it, maybe i clicked it wrong. i've having a hard time with the search function. i also picked up another CAS for $150 shipped, i'll be reselling it as after i bought it realized chances are the meter is wierd and is throwing a decimal up front at that scale. BOTH coils read the same. also you can't get it wrong, if you orient it wrong which is hard to do because it has a tab on one side, it will read Open Loop. also besides having the same value on both coils, the one behind the head light does have spark. i do like the idea of ohming the wires from the connector to the coils! also for $150 i'll now be able to confirm this particular DMM displays values like psychopath.

what would be handy is coil specs, i'll try to post the mitchell 1 specs but, it just references values that it doesn't actually define, it also reference old school tools, like a dedicated ohm meter. i'll likely have to spend a few days just searching "coil" on all of the rx7 boards and sift through and read through. single word searches seem to work to some degree.

I also like the idea of selling the car to a forum member, not sure how married the guy is to the car and it needs a full restoration.

EDIT: for future personal reference: the leading coil is a two-post coil that fires both leading plugs together in a wasted-spark configuration; the trailing coils are two completely separate coils firing the trailing plugs sequentially.

so the leading coil works the trailing does not.

Last edited by cdoublejj; 09-13-23 at 10:04 AM.
Old 09-14-23, 05:26 PM
  #6  
Full Member
 
Jeff76's Avatar
 
Join Date: Jul 2023
Location: Pittsburgh
Posts: 115
Received 38 Likes on 33 Posts
Sorry about the search, I should have check while logged out. Now I can't edit my post. Use the advanced search, Trailing Coil.... drop down, only titles.... click second gen and hit search. The second or third post I remember seeing looked very usefull.

Best of luck with this. Lets us know how all of this goes.
Old 09-15-23, 11:35 AM
  #7  
Moderator

iTrader: (3)
 
j9fd3s's Avatar
 
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,828
Received 2,596 Likes on 1,844 Posts
the system is basically

CAS-> ECU-> Coils. so if the leading coils fire, that means the CAS is working. so best spot to check next is the trailing coil. does it have 12v power?
Old 09-17-23, 01:20 PM
  #8  
Junior Member

Thread Starter
 
cdoublejj's Avatar
 
Join Date: Oct 2013
Location: USA, MO
Posts: 6
Received 0 Likes on 0 Posts
Originally Posted by j9fd3s
the system is basically

CAS-> ECU-> Coils. so if the leading coils fire, that means the CAS is working. so best spot to check next is the trailing coil. does it have 12v power?
i'll likley be looking to sell the new cas since i got for less than$200 but, yes we are going to try and get an igniter or complete trailing unit
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bewst12psi
Haltech Forum
2
07-03-12 04:50 PM
gxl90rx7
2nd Generation Specific (1986-1992)
61
03-27-12 12:11 PM
DiscoQuinn
2nd Generation Specific (1986-1992)
11
12-01-09 12:03 PM
hondacura
2nd Generation Specific (1986-1992)
4
11-30-08 10:31 PM
Redwood
2nd Generation Specific (1986-1992)
9
08-02-02 03:38 PM



Quick Reply: CAS reads .126 ohms



All times are GMT -5. The time now is 01:14 PM.