Good sources for automotive wiring?

[rumblecloud]

I was surprised at how simple the process was. The hard part was where it runs in front of the radiator. Needed to undo the two top support radiator screws and the (i think) the two top condenser support screws in order to get enough room to pull the fat parts of the harness out from its routing position.

But yes, I agree with you. I'll have to swap out the couple of connectors that I had to cut, but I don't feel like that's a big deal since I can do it on the bench. I'll check the continuity and resistance of the suspect wires as I go.

Good thing I now have something to do -- I was getting bored ---yeah...right.

 

[rumblecloud]

Here are some pics of what I got at the pull yard:



Also got the vacuum canister solenoid. Thew two suspect wires ae in the last pic.

 

[rumblecloud]

Before I get into swapping the harnesses, I want to go thru the replaeement harness and check continuity and resistance (PIA, but necessary I thinkk). Is checking resistance as simple as using the OHM setting and using a probe on the each end of the wire being measured? (No power to the wire). I think this is the way to do that.

Before I start, I am not 100% convinced the wiring from the ECM to the MAF is the issue even though I got the 157 code. I've checked the battery voltage (red on the MAF) and that's okay12.46. The ground (black on the MAF) shows very little resistance. The feed back wire (Blue/Red) from the MAF to the ECM is doing what it's supposed to do, fluctuating between .04 to 1.whatever when you blip the throttle, But the ground (Tan/blue) from the MAF back to the ECM is what's in question. It has continuity and some resistance, but not much.

Is there a way to check the voltage passing thru a ground wire?

Thanks in advance.
R

 

[Curious Hound]

Before I get into swapping the harnesses, I want to go thru the replaeement harness and check continuity and resistance (PIA, but necessary I thinkk). Is checking resistance as simple as using the OHM setting and using a probe on the each end of the wire being measured? (No power to the wire). I think this is the way to do that.

Yes

Is there a way to check the voltage passing thru a ground wire?

Voltage does not pass through a wire. Current does. The voltage at both ends of a ground wire should be 0. If your ground wire resistance is 0 ohms, it's good.

 

[rumblecloud]

hahhahaha...welll excuuuuussssse me.

Current it is. Thanks Eric.

 

[rumblecloud]

Pulled the entire harness today and managed to get every plug disconnected and removed safely -- except for the horn plug. Had to cut that wire as it is in an ungodly location. Took about 40 images to help with the install. Tomorrow I'll go about comparing plugs and checking continuity and resistance, wiring colors, etc. And of course cleaning everything. Loads of monotonuous fun.

 

[rumblecloud]

A question on measuring "CURRENT."
I ask this because of a RonD post in another string and I wnat to make sure I understand it correctly.
Using my multimeter with the red lead on a red power wire in a circuit and the black lead on the neg post of the battery I should get battery voltage (12.65V or whatever).
Then I switch the red lead from the multimeter to the black wire of the circuit and the black lead from the mutlimeter to the positive post on the battery I should get the same 12.65V but in a negative form, ie: -12.65V? (digital readout).

I've done this a couple of times and it seems to work. Apologies for simplistic questions. Whenever I try to look this up I get convuluted results.

Thanks for putting up with this

 

[Curious Hound]

A question on measuring "CURRENT."
I ask this because of a RonD post in another string and I wnat to make sure I understand it correctly.
Using my multimeter with the red lead on a red power wire in a circuit and the black lead on the neg post of the battery I should get battery voltage (12.65V or whatever).
Then I switch the red lead from the multimeter to the black wire of the circuit and the black lead from the mutlimeter to the positive post on the battery I should get the same 12.65V but in a negative form, ie: -12.65V? (digital readout).

I've done this a couple of times and it seems to work. Apologies for simplistic questions. Whenever I try to look this up I get convuluted results.

Thanks for putting up with this

That is correct, except; you are measuring voltage. Not current.

Voltage is a term for potential energy in a circuit. Higher voltages can do more work. Voltage is similar to Pressure (psi) in a fluid system. That is a rough comparison. Current is term for how much energy (how many electrons) are flowing in a circuit. Similar to how many gallons per minute are flowing in a fluid system.

A certain amount of current flowing in a circuit of a particular voltage indicates how much power is being used - watts. Voltage multiplied by current gives power. E(volts) x I(amps) = power(watts)

So, in your home, a light bulb being powered by 120volts and flowing 1/2Amp is a 60watt light bulb.

In your car, a 55watt headlamp bulb in the 12volt system will draw 4.583amps.

 

[rumblecloud]

Damn it. I'm trying Eric.
I have never been able to get the whole volts, amps, watts thing. Don't know why, but I just can't get it. I know what happens when I grab onto a hot wire though.

This:
E(volts) x I(amps) = power(watts)
Helps a lot.

Thank you.

r

 

[sgtsandman]

Damn it. I'm trying Eric.
I have never been able to get the whole volts, amps, watts thing. Don't know why, but I just can't get it. I know what happens when I grab onto a hot wire though.

This:
E(volts) x I(amps) = power(watts)
Helps a lot.

Thank you.

r

Don't feel bad. I have to keep looking up the formulas myself in figuring the volts, amps, watts thing, and I have some training on the subject. I just don't do it for a living, which may be why it hasn't been memorized yet.

 

[SenorNoob]

I have an app for that.

Electrical Calculations

Seriously, doesn't get much easier than this.

 

[rumblecloud]

Just a quick update on my MAF issue. Still have not isolated the the 157 code. Swapped out the Tan/Blu wire from the PCU to the plug , but still get the 157 code. Ran a jumper wire from the Tan/blu to batt neg to make sure it was getting a solid ground and nothing changed. So my next guess is to look for vacuum leak somewhere - so far I haven't found anything obvious though.

 

[rumblecloud]

Update....AAARRRRRRGGGGHHHHH....ok that's about it.
Four wires to the MAF: KOEO

Red = Battery Voltage = good
Black = Battery Voltage = good
MAF Ground = 1/2 of Battery Voltage EXACTLY 1/2
MAF Signal wire = fluctuates with throttle within range

Checked for leaks none
"NEW" MAF (third one)

Cleaned the MAF
New Air Filter
ECM grounds all cleaned

Just not sure where to look next. She runs well when at speed. RPM at start-up go to abt 1100, then drop to abt 6-800 rom. Warmer is better.
Doesn't matter if the MAF is plugged in or not - makes absolutely no difference.

Someone please throw me a line...thanks,
R