94 1500 Progress

redheartbeat: i dont have my NP harness installed yet...wanted to do it yesterday but the rain stopped me :(

Gramercy, Louisiana

i have a 18ga pink wire thats coming out of the fuse box(dunno what it went to :x ) i also have the large pink wire from the coil they both get 12v with the key on, 0v with key off.
grey wire 0v with key on or off
purple wire 5v
black is grounded

im going to try the 12v to the grey wire when i get home. i honestly think the ground by the fill neck is killing it. worse come to worse, ill just run the red lead wire from NP harness to my grey wire to give me the 12v i need.
on my fuel relay my orange wire gets 12v from the junction box, the red gets nothing. if i jump orange to green the relay clicks. if i tie the red, green, an orange together it will click, but nothing at the grey wire an the fuel pump does nothing still

i hate wiring..

thanks for all the help..anymore ideas will be great.

dammit man, get that harness in there, its a 5 minute job! :laugh:

i know!!! thats what makes me mad :( i have a car port an the rain was being blown under the car port.
im going to install it after i get my LTs installed...hopefully tonight.

Holy crap! Im lost with this wiring stuff! I thought I could just replace the in tank pump go?! Why all this rewiring?

Oh, OK, now I see what you're doing.....
had to go back a few pages!
You're trying to power the pump with the hot wire kit?
Right?
Not the OEM '94 relay your truck has (had) up on the pass firewall. Had me lost there with the color coding.
LOL!
If the NP harness has an intergrated FP relay, the original is still there, AND you've added the one from the hot wire kit, that's about 2 more relays than you need. (wink!)

If it were me, I'd not use the hot wire kit and just put the OEM plug back on the tank end of the FP harness, plug it back in, just like factory, crawl back up front, and check the FP like RedHeartBeat suggested. Jumper 12v to the grey wire coming out of the OEM relay and check your FP for operation. If still no pump buzz, check the OEM fuse next to the OEM relay. Still no buzz, check for 12v in the grey wire at the tank and check your pump to chassis ground.
If that all checks out, see if the OEM relay has power coming in (constant 12v) WITHOUT having to jumper from an outside source. (Probably red wire) That'll tell you if the truck harness still has a constant 12v feed to power the pump.
Once that's established, try tripping the OEM relay, and see if your pump powers up.
Jumper 12v to the low side of the relay. If the relay closes, and the pump runs, you're almost home.....

Then all you should have to do is trip the OEM relay with the FP control wire from the NP harness....(maybe!)
If you want to check the pump for operation after the ECM times out, just pull the OPS plug and jump across the
two terminals that AREN'T for the OP dash guage.
You're just "faking" oil pressure and making sure the OPS is closing and taking control of the FP after the engine starts. One side of your OPS should be 12v keyed power.
(Usually orange wire)
Hope I didn't confuse you more........hell, sometimes I confuse myself! LOL!

If I'm steering you wrong, somebody jump in and correct me. I'm just going off memory..........old, tired memory!

flattopwill.......Pretty sure you're right.
All the LS 'puter and NP harness should have to do is trip the OEM relay just like the original '94 ECM did.
One wire.........ECM FP "out" to OEM truck relay.
Let the original truck wiring do it's thing with the OPS safety still in play.
Upgraded Walboro pump on stock sender, powered by the stock FP wiring, through the stock OEM relay, protected by the stock OEM fuse, just tripped by the new harness/ECM.

I think the FP hot wire kit keniff has is for applications
where there may not be an OEM harness with an existing relay already there. Just my thought.......

lmao
im confused already.

jon @ NP told me i can by pass all of that with his red feed wire.

my hot wire kit is getting 12v from the ALT hook up to the relay. i should get 12v to the relay (Red) when the key is turned on (fed from the grey wire) i should then get 12v at the (Red and Grey) sending 12v to the fuel pump. if that makes sense.

exact quote from Jon @ NP
Take our red wire straight to the positive side of the
pump (Grey) and ground the other side of the pump (Black) Leave the purple (sender) alone.
that will bypass the factory stuff but still allow my fuel gauge to work. ill then cut the black wire from the factory harness an just ground it to the frame.
im going to move the relay so its easier to work on. its becoming a pain with it so close to the fill tube.

Quote:

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Originally Posted by Hardrock

flattopwill.......Pretty sure you're right.
All the LS 'puter and NP harness should have to do is trip the OEM relay just like the original '94 ECM did.
One wire.........ECM FP "out" to OEM truck relay.
Let the original truck wiring do it's thing with the OPS safety still in play.
Upgraded Walboro pump on stock sender, powered by the stock FP wiring, through the stock OEM relay, protected by the stock OEM fuse, just tripped by the new harness/ECM.

I think the FP hot wire kit keniff has is for applications
where there may not be an OEM harness with an existing relay already there. Just my thought.......

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if you go into the electrical section you'll see the OBS hotwire upgrade that REDHEARTBEAT did.
i dunno why im having all these problems..this is my first time with the FP wiring. i havent checked the ground yet bc its a pain to reach. im just going to move everything an make it easier on myself.

Quote:

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Originally Posted by flattopwill

Holy crap! Im lost with this wiring stuff! I thought I could just replace the in tank pump go?! Why all this rewiring?

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the Walbro i used has a different plug in on the fuel pump. its got the ground, then another ground that clamps with a hose clamp, then a red lead wire that comes on to power the FP. i left the red wire an the ground alone on the connector that plugs up to the basket. i moved the sender wires an i made sure they went exactly how the old one was. only thing that didnt match up was the lettering.
A B
C D

OK, cool. I just checked out the Hot Wire thread.
Didn't realize it was a proven, accepted upgrade.
Looks like a good idea especially with the extra draw
the Walboro takes.
Had no idea it sucked so much juice! LOL!

Stacked relays, one over the other.......works.
Still have your OPS in the primary side, first relay....nice.
Lookin' good Keniff. You'll get it figured out.

On the pro street S-10 we just upgraded the OEM grey pump feed to a 10 ga. wire and a beefy ground at the frame. The relay stayed OEM on the Key/OPS side.
Saftey, ya know.. Holley blue pump, fuel cell, etc.
Only work-around.....
Little red button on the dash primed the system.