Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

HELP!! got a strang phenomenon

Discussion in 'The Garage' started by VisionxOrb, Nov 26, 2002.

  1. VisionxOrb

    VisionxOrb 1/2 ton status

    Joined:
    Oct 10, 2001
    Posts:
    251
    Likes Received:
    0
    Location:
    Newbury Park, Ca
    Ok heres the deal. Got one of the those fancy autometer air/fuel ratio gauges. got a new oxy sensor put end on the wires plug it into my gauge put it in run it. now with only the engine on it looks like it reads accruate ( says rich and my nose says so to ) now when i touch the gas or turn one any thing ( and i mean anything, lights, stereo, blinkers, whipers ) it reads much leaner. so i first figured something wrong in the power to the gauge but the voltage there is good so i hooked up my digital multimeter to my oygen sensor its self to read the output. now here are where things get crazy. at idle everything off it reads about 750mv ( rich ) but anytime i turn anything on the reading actually drops from the 02 sensor. my stereo makes the reading go don to about 350mv ( near lean ) and when i give it a little gas it even drops more ( infact it started reading negative ) WTF . how/what is happening and how do i fix this ( this would really mess up a EFI car and i want to convert ) im stumped.
     
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    At idle the alternator is often spinning to slow to provide full power. You getting a voltage drop. You might also want to check the body grounds. THe main body ground is off the back of the passengerside head to the fire wall. It is often forgoten about when the engine or heads are pulled and will cause a ton of crazy little problems.
     
  3. chulisohombre

    chulisohombre 1/2 ton status

    Joined:
    Apr 11, 2002
    Posts:
    4,141
    Likes Received:
    14
    Location:
    Bangor,Pa
    i was going to say the same thing as grim but he beat me to it.i had the same problem with all of my guages not reading good.and when i turned on the blinkers it would make the guages go back and forth with the power.i added a ground wire to the cluster itself and thaty fixxed the problem.the ground has a lot to do with the way a guage reads.so if the ground you are using for the ox sensor isnt the best it will give you all kinds of funky readings.
     
  4. VisionxOrb

    VisionxOrb 1/2 ton status

    Joined:
    Oct 10, 2001
    Posts:
    251
    Likes Received:
    0
    Location:
    Newbury Park, Ca
    I thought of voltage problems 2 but i checked it and the lowest it goes with my 200 amp alt is 13.25 ( checked at the fuse box )volts under load at idle( about 50 amps of lights ). plus its not my gauge cause i hooked the mulitmeter directly to the 02 sensor which has no positive only ground and signal. and i ran another wire to the ground of it directly plus throught the frame and ohmed it out it was only .5 ohm. Ive thought maybe power is some how "bleeding" back into the ground causeing its potential difference to drop but thats just a thereoy. also my alt is a cs-144 if there anything funky with those.
     

Share This Page