Underhood wiring.

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ClovisMan
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Underhood wiring.

Post by ClovisMan »

So i'm just getting around to wiring. A few years ago I pulled the engine and had it rebuilt. Ive added an Edelbrock intake and a Holley carb and removed all emissions stuff. So today I was relooming all the wires under the hood and let me tell ya, Jeep did a rigged up job with wiring, LOL. There is actual duct tape and wires that just all terminate together. My question is about a set of orange wires that all terminate together. One wire has a connector that goes to the oil pressure switch and then to the e-choke of the carb. The other 2 i believe went to junk that I no longer have under the hood like carb bowl vent and carb solenoid. I got this from here: http://oljeep.com/gw/elec/86/86_FSJ_Wir ... age2-6.gif

So now my question. Are these 2 wires 12v keyed sources I can use to say trigger the electric pump relay or anything else that requires 12v only when the key is on?
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88 Grand Wagoneer - The Money Pit - 360/727/NP208 - SOA/SF - Lots of other stuff SOLD
78 Cherokee Chief - Copper - 360/TH400/Quadratrac - 4 inch BDS lift - 33 inch tires SOLD

csuengr
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Re: Underhood wiring.

Post by csuengr »

The orange wires are key switched 12V. Hot in run only.

That harness was made pre heat shrink days. Those are splices. Very common. The splices are soldered and the tape is for insulation. For a while now splices have been ultrasonically welded and covered in adhesive lined heat shrink.
1977 Cherokee S, Ford 5.0, 5 speed, BW 1356, 33 x 10.50 BFG's. No longer my DD.
2007 Mercury Milan, 2.3L, 5-speed, now my DD. 29 mpg average.

FSJ Guy
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Re: Underhood wiring.

Post by FSJ Guy »

Be aware that the orange wires that run the choke heater and the car bowl vent solenoid ARE NOT FUSED under the dash. They run directly through the ignition switch and to a fusible link by the starter relay, since you have an 88. If you short out one of the orange wires, it will blow the fusible link and your ignition will no longer work. No ignition, no go. AMHIK. :- (

So, yes you can use it But put a fuse on it.
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!

csuengr
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Re: Underhood wiring.

Post by csuengr »

Thing is, you want your fuel pump running in both run and start key positions.
1977 Cherokee S, Ford 5.0, 5 speed, BW 1356, 33 x 10.50 BFG's. No longer my DD.
2007 Mercury Milan, 2.3L, 5-speed, now my DD. 29 mpg average.
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ClovisMan
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Joined: Fri May 11, 2012 8:10 am
Location: New Braunfels, TX

Re: Underhood wiring.

Post by ClovisMan »

FSJ Guy wrote:Be aware that the orange wires that run the choke heater and the car bowl vent solenoid ARE NOT FUSED under the dash. They run directly through the ignition switch and to a fusible link by the starter relay, since you have an 88. If you short out one of the orange wires, it will blow the fusible link and your ignition will no longer work. No ignition, no go. AMHIK. :- (

So, yes you can use it But put a fuse on it.
Okay, good to know. I will put an inline spade fuse on it and then use it for the fuel pump relay.
88 Grand Wagoneer - The Money Pit - 360/727/NP208 - SOA/SF - Lots of other stuff SOLD
78 Cherokee Chief - Copper - 360/TH400/Quadratrac - 4 inch BDS lift - 33 inch tires SOLD
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ClovisMan
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Joined: Fri May 11, 2012 8:10 am
Location: New Braunfels, TX

Re: Underhood wiring.

Post by ClovisMan »

csuengr wrote:Thing is, you want your fuel pump running in both run and start key positions.
The fuel pump is being wired through a Summit Racing Fuel Pump relay kit. Here are the instructions:
http://static.summitracing.com/global/i ... 890023.pdf

It calls for a yellow wire to be connected to a switched 12v source and the red wire to be on a constant 12v source. Would this orange wire not be sufficient for this?
Fuel pump.JPG
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Last edited by ClovisMan on Fri Apr 01, 2016 1:59 pm, edited 1 time in total.
88 Grand Wagoneer - The Money Pit - 360/727/NP208 - SOA/SF - Lots of other stuff SOLD
78 Cherokee Chief - Copper - 360/TH400/Quadratrac - 4 inch BDS lift - 33 inch tires SOLD
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REDONE
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Re: Underhood wiring.

Post by REDONE »

No, because it drops out during the "start" from what csuengr said. I'm not familiar with those wires so I don't know for sure, but if it's not hot during start then you loose pressure when you're cranking the key.
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.
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ClovisMan
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Re: Underhood wiring.

Post by ClovisMan »

REDONE wrote:No, because it drops out during the "start" from what csuengr said. I'm not familiar with those wires so I don't know for sure, but if it's not hot during start then you loose pressure when you're cranking the key.
Well dang...is there another wire under the hood that would work for this? I've looked at the wiring diagrams on Tom's ol Jeep and now I'm cross-eyed, lol.
88 Grand Wagoneer - The Money Pit - 360/727/NP208 - SOA/SF - Lots of other stuff SOLD
78 Cherokee Chief - Copper - 360/TH400/Quadratrac - 4 inch BDS lift - 33 inch tires SOLD
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REDONE
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Re: Underhood wiring.

Post by REDONE »

You got me bud. On my 79 the choke heater stuff was red with black tracers. Looking at ol' jeep for 88 the ONLY orange splice I see goes to the "air management system". Follow pin 46 from the MCU in this drawing:
http://oljeep.com/gw/elec/88/88_FSJ_Wir ... mPage2.jpg

If you just need to tie into to a hot in run/start to trigger a relay I'd tie into the power for the ignition module. In this oljeep drawing it looks like bottom right is the module and the line power is plain green, NO tracer.
http://oljeep.com/gw/elec/88/88_FSJ_Wir ... mPage1.jpg

EDIT>>> I see the orange splice scuengr is talking about, second diagram above, B-3 and C-3. Choke heater stuff on an 88 is orange.
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.

csuengr
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Location: Sterling, CO

Re: Underhood wiring.

Post by csuengr »

ClovisMan wrote:
REDONE wrote:No, because it drops out during the "start" from what csuengr said. I'm not familiar with those wires so I don't know for sure, but if it's not hot during start then you loose pressure when you're cranking the key.
Well dang...is there another wire under the hood that would work for this? I've looked at the wiring diagrams on Tom's ol Jeep and now I'm cross-eyed, lol.
Use the wire that switches the ignition box. I believe it is blue.
1977 Cherokee S, Ford 5.0, 5 speed, BW 1356, 33 x 10.50 BFG's. No longer my DD.
2007 Mercury Milan, 2.3L, 5-speed, now my DD. 29 mpg average.

FSJ Guy
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Re: Underhood wiring.

Post by FSJ Guy »

Since the OP is using a carb, having the fuel pump cut out during cranking isn't THAT big of deal, is it? The bowl should have enough fuel....
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!
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REDONE
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Re: Underhood wiring.

Post by REDONE »

You're right, I have TBI on the brain. :oops:
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.

csuengr
Posts: 1290
Joined: Sun Mar 24, 2013 10:24 am
Location: Sterling, CO

Re: Underhood wiring.

Post by csuengr »

FSJ Guy wrote:Since the OP is using a carb, having the fuel pump cut out during cranking isn't THAT big of deal, is it? The bowl should have enough fuel....
I have always done it with the pump on in run and start, just in case.
1977 Cherokee S, Ford 5.0, 5 speed, BW 1356, 33 x 10.50 BFG's. No longer my DD.
2007 Mercury Milan, 2.3L, 5-speed, now my DD. 29 mpg average.
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REDONE
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Joined: Tue Sep 13, 2011 5:48 pm
Location: Lakewood and Bailey, CO

Re: Underhood wiring.

Post by REDONE »

csuengr wrote:
I have always done it with the pump on in run and start, just in case.
Makes sense. If the fuel boils off in the carb you'd want the pump to fill it while cranking, anyone who's been to Ouray has seen that happen.
79 J-10 (Honcho Mucho) KE0LSU
304/Performance Fuel Injection TBI/MTA1/SP2P/Magnum rockers
T18/D20/D44s&4.10s/33" Mud Claws
Grizzly Locker Rear
4" front spring drop, 5" rear shackle flip
Chevy style HEI (ECM controlled)
Dolphin "Shark" gauges in a fancy homemade oak bezel
3/4 resto, rotting faster than I've been fixing it.
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