Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
MIKE I need help
Author Message
irving Offline
Member
***

Posts: 17
Joined: Nov 2007
Reputation: 0
Post: #1
MIKE I need help
Hi Mike
I need help every time I read the forum I get more confused
I read.
I have your single EFIE connected to the upstream O2 sensor.
The wire colors on the O2 sensor harness are black grey white and white.
I have the black wire split with the green wire on the sensor side and the
white wire on the computer side. With the EFIE powered on the black wire
to ground shows fluctuating voltage from .4 to .9MV. From black to red shows .300MV. From red to ground shows .7 to 1.2MV” [/color]

What does it mean the black with the green and the white on the side of the computer?????I have been trying to found the signal wire on my, but it make no sense to me

“If none of these options are available, you'll need to locate the oxygen senor and locate the wire that way. Unfortunately the sensor will have 2, 3 or 4 wires, and you have to know which one is the signal wire. The other wires will be ground, a heater wire (used to heat the oxygen sensor when the vehicle is first started), or the heater circuit ground (separate from the signal ground). Disconnect the wire harness, turn on the ignition and probe for 2 wires that produce 12 volts. This will be the heater circuit. The two wires left will be the signal and the signal ground. Reconnect the wiring harness, then strip a little insulation off each of these wires and measure them with the engine running. You'll get voltage readings constantly fluctuating between 0 and 1 volt, if you have the signal and signal ground. If the readings are negative, reverse your probes. Now the positive probe will be the signal wire you've been looking for. Cut this wire at a convenient location for connecting the EFIE. We'll call the sensor side of this cut the sensor wire, and the other side of the cut, the computer wire.

MY have 4 wire black, grey, white, white .then it change to black, yellow /w strip, white, orange
the heater circuit ground (separate from the signal ground) how do I know signal ground and heater ground??
When I test for 12v I get 12v on 2 wires with different ground them it looks like it change from + to – on the same leads
Do I check each wire to the truck chassis ground??
No to each other?

I do not see the voltage changing like you say; does it change rapid or slow?
If I disconnect the O2 sensor does the engine light will come on?
My eng light check ok when I turn the ignition switch on but it does not come on with the O2 sensor disconnected is that normal?

1. (What is the voltage reading of the signal wire to ground, with the engine running and while it's disconnected from the ECU? Reading the output from the sensor only, with the ECU out)

what do you mean?
I did not find any that read 0 or1 they all change but no fast like you say
my computer is an OBdI does that make a difference?
4. HELP:question:Crazy
(This post was last modified: 11-23-2007 04:56 PM by irving.)
11-23-2007 04:52 PM
Find all posts by this user Quote this message in a reply
mike Offline
Senior Member
****

Posts: 2,020
Joined: Jul 2007
Reputation: 7
Post: #2
RE: MIKE I need help
Hi Irving,

I'm sorry it was confusing. I'll answer your questions in order:

In testing your oxygen sensor wires, yes you check them to ground (not to each other). You shouldn't get 12 volts on 2 wires, only one. So, if you get 12 volts to ground, that's your heater wire. For ground wires, you'll get 0 volts to ground. The previous tests must have at least the car's key switch turned on, but the engine doesn't have to be running.

For the signal wire you'll get a fluctuating voltage that changes very rapidly, probably too fast for your multimeter to show you, but you should still get some kind of average, such as .4 to .6 volts, with the value constantly changing. Note that for the signal wire, the engine has to be running for a few minutes which allows the sensor's heater to warm the sensor up so it can output proper data.

If you disconnect the oxygen sensor, yes the engine light will come on, but it may take a while before it comes on. It's not a problem though, you just plug it back in. If it doesn't go back out, you can disconnect the battery's ground for a minute or so to reset your computer.

You quoted an instruction I gave another user about disconnecting the sensor output from the ECU (Emission Control Unit also-known-as the Computer). You don't need to do this. That was a specific instruction to him because we had to make sure he didn't have a blown computer.

I don't know what an OBDI is. Can you tell me what the letters stand for? Is it a manufacturer? However, it doesn't really matter what kind of computer you have. You have what is known as a "narrow band" oxygen sensor, and these all work the same. For a 4 wire unit you'll have a heater wire (12 V+), and heater ground (0 V), and signal coming from the sensor (variable voltage in the 0 - 1 volt range), and a signal ground (0 Volts). You should be able to establish which is which from the instructions above.

However, if you can't you can always get your wiring diagram from ahdol.com. See step 1 of the installation instructions, which can be found here.

If you're still confused about something, write back and we'll get it straightened out.

Mike

[Image: signature.gif]
Visit Our Documents Page
11-23-2007 05:42 PM
Visit this user's website Find all posts by this user Quote this message in a reply
irving Offline
Member
***

Posts: 17
Joined: Nov 2007
Reputation: 0
Post: #3
RE: MIKE I need help
Hi again Mike
OBD1 and OBD2 is an On-board dianostics version for all the cars on-board computer
Why I am getting 12v on 2 wires? O so it look like,my eng light is off. I will try againg tomorrow and I will let you Know,
Mike how do I differentiate the heater ground and the signal ground ,they are 4 wire 2 whites 1 black and 1 grey do you have an idea what is the signal wire?:question:
(This post was last modified: 11-23-2007 07:31 PM by irving.)
11-23-2007 06:19 PM
Find all posts by this user Quote this message in a reply
mike Offline
Senior Member
****

Posts: 2,020
Joined: Jul 2007
Reputation: 7
Post: #4
RE: MIKE I need help
Ok, I understand. It must stand for On Board Diagnostic (program).

If you are getting 12 volts on 2 wires, it sounds like you have a fried oxygen sensor. I'm assuming you're getting 0 volts on the other two wires. I'm also assuming you're testing for the signal wire after the engine has been running a few minutes so the sensor has time to warm up. Correct? If this is all correct, you probably have a bad oxygen sensor and need to get this checked out. However, you should have had an engine light on before you started all of this, but you didn't report that. That's the only thing that makes me doubt that your sensor has gone bad.

As for which ground is which, it doesn't matter, as you won't use either of those wires. If you really want to know which is which, get your wiring diagram from ahdol.com, and it will tell you. Getting your wiring diagram for $4 is the cheapest way to find out what all 4 wire colors are for. Then if you're getting 12 volts from your signal wire, you can know that the sensor is shot.

If the sensor is shot, putting a new sensor in will improve your mileage all by itself. But then you'll be able to do better than that with your electrolyzer and EFIE.

What is the make/model of your car/truck and what year is it? The sensors do go bad after a while. I had to replace one on a 95 car I'm using. It produced voltage up around 10 - 12 volts and caused my engine light to be on until it was replaced.

[Image: signature.gif]
Visit Our Documents Page
11-23-2007 07:45 PM
Visit this user's website Find all posts by this user Quote this message in a reply
irving Offline
Member
***

Posts: 17
Joined: Nov 2007
Reputation: 0
Post: #5
RE: MIKE I need help
Mike it is a class A motor Home 1998 on a 1997 ford chassis w a/ 7.5 ford eng (460ford)
I am going to put a Magdrive 12a w/ 2 brick for a 8 liter a min of hho do not know if I will be needing to change the efie to make it leaner as I will be using a system for a bigger engCrazy
I do not know for sure if i was cheking the wires correctly so I will check againg tomorrow
(This post was last modified: 11-23-2007 08:06 PM by irving.)
11-23-2007 08:03 PM
Find all posts by this user Quote this message in a reply
irving Offline
Member
***

Posts: 17
Joined: Nov 2007
Reputation: 0
Post: #6
RE: MIKE I need help
Hi Mike finally I have found the signal wire, I have headers on the engine so the O2 sensor did not get hot enough on idle to make voltage, but after step on the gas for a couples of min it got hot enough to star working, it is the grey wire
I have a question, I am installing a air/fuel gauge and it connect to the signal wire. where do I connect the gauge on the sensor side or the computer side of the efie:question?:question:
11-24-2007 03:34 PM
Find all posts by this user Quote this message in a reply
mike Offline
Senior Member
****

Posts: 2,020
Joined: Jul 2007
Reputation: 7
Post: #7
RE: MIKE I need help
That's great news.

You would want to connect it to the computer side, as this is the signal that the computer is using for it's air/fuel calcs.

[Image: signature.gif]
Visit Our Documents Page
(This post was last modified: 11-24-2007 05:39 PM by mike.)
11-24-2007 05:38 PM
Visit this user's website Find all posts by this user Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)