Want to do Compression check - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 07-01-2007, 03:15 PM   #1
Junior Member
Thread Starter
 
Join Date: Oct 2006
Location: Edmond, OK
Posts: 473
Total Cats: 0
Default Want to do Compression check

I was wanting to do a compression check and I was wondering what the best way to disable the ignition is?
Rage_Kage is offline   Reply With Quote
Old 07-01-2007, 06:46 PM   #2
Elite Member
iTrader: (11)
 
Trent's Avatar
 
Join Date: Feb 2006
Location: Louisiana
Posts: 1,625
Total Cats: 5
Default

What I would do is pull the two harnesses off of the CAS.
Trent is offline   Reply With Quote
Old 07-01-2007, 06:48 PM   #3
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6
Default

The cas only has one harness that i know of.

Pull the connectors off the coils and pull the fuel injection fuse in the fusebox. Hold the throttle to the floor.
cjernigan is offline   Reply With Quote
Old 07-01-2007, 11:17 PM   #4
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

I just pull the wires for the injector harness and coils.
Braineack is offline   Reply With Quote
Old 07-02-2007, 10:25 AM   #5
Junior Member
 
Join Date: Sep 2006
Posts: 225
Total Cats: -4
Default

unplug the cas
Uncle Arthur is offline   Reply With Quote
Old 07-04-2007, 10:00 PM   #6
Senior Member
 
Join Date: Mar 2006
Location: Ireland
Posts: 534
Total Cats: 0
Default

Can somebody please explain to me what the heck is goin on here ?
I thought that you'd need some type of measuring equipment to do a compression check ?
Fergus is offline   Reply With Quote
Old 07-04-2007, 11:07 PM   #7
Senior Member
iTrader: (4)
 
Join Date: May 2007
Location: Ontario
Posts: 790
Total Cats: 0
Default

Quote:
Originally Posted by Fergus View Post
Can somebody please explain to me what the heck is goin on here ?
I thought that you'd need some type of measuring equipment to do a compression check ?
Yes, A compression tester. However to use the compression tester you need to crank the engine, you don't want fuel and spark when you are cranking it just to test compression.

Everyone above is describing ways to cut fuel and spark.
reddroptop is offline   Reply With Quote
Old 07-04-2007, 11:24 PM   #8
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

Quote:
Originally Posted by Fergus View Post
Can somebody please explain to me what the heck is goin on here ?
I thought that you'd need some type of measuring equipment to do a compression check ?
yeah it's a pressure gauge, thats about it.

you stick it in the spark plug hole and you crank the engine...this measures how much compression you are making in each cylinder.
Braineack is offline   Reply With Quote
Old 07-05-2007, 05:42 PM   #9
Senior Member
 
Join Date: Mar 2006
Location: Ireland
Posts: 534
Total Cats: 0
Default

Ah cool.
Thanks for that 8)
Fergus is offline   Reply With Quote
Old 07-05-2007, 05:47 PM   #10
Elite Member
iTrader: (14)
 
Join Date: Mar 2006
Location: Edmonton, AB
Posts: 4,921
Total Cats: 0
Default

Pull the fuel injection relay and crank away.
jayc72 is offline   Reply With Quote
Old 07-05-2007, 05:54 PM   #11
Senior Member
iTrader: (1)
 
Join Date: Aug 2006
Location: Illinois
Posts: 1,011
Total Cats: 7
Default

Quote:
Originally Posted by Uncle Arthur View Post
unplug the cas
Correct.
lazzer408 is offline   Reply With Quote
Old 07-05-2007, 05:55 PM   #12
Senior Member
iTrader: (1)
 
Join Date: Aug 2006
Location: Illinois
Posts: 1,011
Total Cats: 7
Default

Quote:
Originally Posted by jayc72 View Post
Pull the fuel injection relay and crank away.
Incorrect. Not with a wasted spark ignition system unless you ground the plug wire you removed. If you don't you have 30,000volts that has to go somewhere and it can ark inside the coil internally and blow an ignitor.
lazzer408 is offline   Reply With Quote
Old 07-05-2007, 06:09 PM   #13
Newb
 
Join Date: Jun 2007
Location: Charlotte / Morehead City
Posts: 10
Total Cats: 0
Default

pull fuel fuse and remove wires. good to go
MotorManiac is offline   Reply With Quote
Old 07-08-2007, 11:32 PM   #14
Junior Member
 
Join Date: Sep 2005
Location: The Golden Triangle, Ontario
Posts: 283
Total Cats: 0
Cool

Quote:
Originally Posted by jayc72 View Post
Pull the fuel injection relay and crank away.
That's what I did and it worked fine for me!

Now I am tearing her down for a head rebuild
blue89turbo is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 12-13-2017 10:04 PM
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
Any pnp megasquirt for 2001 Big_gumby WTB 0 09-30-2015 04:34 PM
3rd Time's a Charm...hopefully. zephyrusaurai Meet and Greet 2 09-28-2015 11:59 PM
Another Alternator thread ihiryu General Miata Chat 9 09-28-2015 11:22 AM


Thread Tools

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 Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 06:23 AM.