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Explorer OBD2 Harness Re-work

Papa Turdly

New Member
Joined
Jun 22, 2005
Messages
16
Ok, one more question now that I am back home and going to start back on my truck. Does the Ford computer need to recognize the inertia switch to make the fuel pump work? I am integrating this harness into a ‘99 Jeep Cherokee and am planning on using the Jeep factory relay center, which I don’t believe uses the inertia switch.
 

garberz

Bronco Influencer
Joined
Jun 24, 2007
Messages
6,856
Loc.
Conejo Valley, Ca.
Ok, one more question now that I am back home and going to start back on my truck. Does the Ford computer need to recognize the inertia switch to make the fuel pump work? I am integrating this harness into a ‘99 Jeep Cherokee and am planning on using the Jeep factory relay center, which I don’t believe uses the inertia switch.

Nope, the PCM provides a ground signal to energize the fuel pump relay. Once the relay closes, the load is sent through the inertia switch then on to the fuel pump. The PCM only sends ground to the relay, it has no idea what the relay operates. This is when using our simplified harnesses.

Mark
 
OP
OP
EFI Guy

EFI Guy

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Apr 14, 2013
Messages
1,049
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The inertia switch is just an inline switch between the relay and the pump. I recommend adding it in for safety reasons but the PCM doesn't need to see one. However, the PCM does monitor the fuel pump circuit for power, so the output of your relay should feed pin 40 as well as your pump.
 

Rocko1012

Full Member
Joined
Nov 20, 2016
Messages
225
O2/wire

I believe i am on the right track for wire another from O2 Sensor
Pleas look at pictures and let me know. Do in splice into yellow and red from the other o2 sensor. Can I Delete other plugs in those pics. EGR Stuff
 

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OP
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EFI Guy

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The plugs in red are EGR. You don't splice into the other o2 on those colors though. They only share orange, and blue/orange.

2hy5CBp.jpg


mlMAYGG.jpg
 

Rocko1012

Full Member
Joined
Nov 20, 2016
Messages
225
O2 Sensor

After sleeping on it, I have to say my last post was not to bright. I was not thinking of left and right side sensors. 2 separate circuits. I have to go back and ensure I did not remove wires completely from PCM. Used the above to get my 02's wired up correctly, Had to add wires back into PCM plug.
Thanks Gary for picture

Cut off trans plug from engine harness and removed all wires that were cut from pcm & C115. Will i need to do anything to engine harness, for High Idle/no A/c (41, 69, 86) off of C115

Ron
 
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bigmuddy

Contributor
Bronco Guru
Joined
Dec 28, 2004
Messages
7,001
Loc.
Marthasville Missouri
Admin is there an award for selfless helping of fellow bronco travelers? If so, EFI guy deserves one for the information he has provided...
 

wsager

Full Member
Joined
Dec 3, 2014
Messages
333
Are the videos down, or is there something wrong with my computer and phone?
 
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EFI Guy

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The videos are still there, it's some sort of problem with mixed content being blocked on HTTPS sites by both Chrome and Firefox and possibly others. The quick fix is to just enable it in the browser for the webpage you are on if it's trusted.

Error.jpg
 

Joker11

Sr. Member
Joined
Sep 11, 2008
Messages
840
Loc.
Yuma, Arizona
I may have asked this before so I apologize.

If I have a complete explorer as a donor, and I transfer everything over to the bronco, why do I need to modify the harness?
 

904Bronco

Contributor
Bronco Guru
Joined
Sep 28, 2004
Messages
5,749
Loc.
San Martin, CA
I may have asked this before so I apologize.

If I have a complete explorer as a donor, and I transfer everything over to the bronco, why do I need to modify the harness?

Because not everyone wants to keep all the smog equipment, then there is the fuel evap circuit that briefly pressurizes the fuel tank looking for leaks, I am a little slow this morning, so I don't have the name, but there is also a key security system that needs to be disabled on the later models...
 

ngsd

Contributor
Bronco Guru
Joined
Mar 2, 2019
Messages
2,531
Airbags, rollover, alarm, ignition, seat/seat belt sensors, smog, and more. Why would you want to transfer all of this to an EB?
 
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