300ZX (Z32) Forums Dedicated to 90-96 ZCars otherwize known as the Z32's

No Check Engine Light when switch is open ?

Thread Tools
 
Search this Thread
 
Old 05-02-2015 | 04:16 PM
  #1  
jonhy93's Avatar
Thread Starter
Registered User
 
Joined: Apr 2015
Posts: 3
No Check Engine Light when switch is open ?

I already posted this once but I lost my other phone with my login info but anyways trying to smog my car but it wont pass due to a functional test obd port doesnt work and check engine light does not turn on when i open the switch. i checked the dash and it gets + but not - atleast thats my conclusion i bought a multimeter but cant figure out how to use it anyways i went to the computer to see if anything was up there and it looks like the wires there have been modified ( i will post a picture down below) so now i need your guys help ... any info would be great thanks !

Name:  300zx%20wiring%20harness.jpg
Views: 505
Size:  81.2 KB

Name:  300zx%20wiring%20harness%202.jpg
Views: 461
Size:  61.0 KB
Old 05-04-2015 | 04:48 PM
  #2  
jonhy93's Avatar
Thread Starter
Registered User
 
Joined: Apr 2015
Posts: 3
No one ?
Old 05-04-2015 | 06:36 PM
  #3  
zxguy1986's Avatar
Registered User
 
Joined: Aug 2013
Posts: 1,103
Thanks for your post.

I looked at your photos and did not see where anything was 'modified' unless you mean the maybe-by-hand-wire-splices I maybe see. Hard to know why anyone would do that unless you can check each of those wires to its end point at the ECU and figure out what signal they were supposed to carry.

I have seen diagrams that can trace every input and output at the ECU and, yeah, takes a genius or definitely someone with no attention span deficits to follow them. At this point, you could use a circuit tester instead of a multi-meter. Turn ignition on and see if every input/output at your ECU is live (getting/giving a signal). Your circuit tester should light up and beep. Dead circuits don't.

Your quickest maybe-fix would be find another harness section (recycled?) for the one in your fotos and swap it in to see what operates differently after the swap. There are no short cuts when POs start messing with your electronics and then leave their mess behind. They never tell you what or why...

PS: States that rely on the car's own electronics for pass/fail emissions tests are real boneheads. Just test what comes out of the dang exhaust at various RPMs/speeds. It 'pollutes' or it 'passes.' What's the big deal with electronics, esp on older models?

Last edited by zxguy1986; 05-04-2015 at 06:53 PM.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
jonhy93
300ZX (Z32) Forums
2
04-02-2015 08:27 AM
drifto
300ZX (Z32) Forums
2
09-21-2012 01:37 PM
3riCJbOi
300ZX (Z32) Forums
11
08-20-2008 10:16 PM
fozs00
300ZX (Z32) Performance / Technical
2
04-25-2005 12:54 PM
speedracer1
300ZX (Z32) Performance / Technical
1
11-18-2002 10:50 PM




All times are GMT -7. The time now is 12:48 PM.