Please help identfy plug in engine ***problem fixed***, Why is it wired to fuel pump trigger???? Options

[1stworks]

73 2.0 d jet.
The red wire runs to front of car.I assume to fuel pump bc when i put power to it i hear pump run.
Now the only way to start car is to put my power probe to that red wire.Dont give the red wire any power/ground just touch the probe whitch goes direct to battery And it fires right up??????
So what is the plug for and what does it have to b wired in like that?

(IMG:http://www.914world.com/bbs2/uploads_offsite/i1315.photobucket.com-15718-1384282776.1.jpg)


Thanks for any help!!!!!

[jimkelly]

this car originally had fuel pump in engine bay and someone moved it to front trunk - is my guess.

that cut black/red wire should have 12v to it when your turn ignition all the way.

[SirAndy]

So what is the plug for and what does it have to b wired in like that?

Because someone hacked into your harness ... (IMG:style_emoticons/default/icon8.gif)


The plug is for the stock fuelpump which used to be in the engine bay under the shelf.
(IMG:style_emoticons/default/shades.gif)

[jimkelly]

your probe must be acting like a ground, grounding the plug.

[r_towle]

when you turn on the key, you will only have power for 15 seconds to prime the pump.
Then when you are in starting mode, it also has power.
And again while running.

Rich

[1stworks]

your probe must be acting like a ground, grounding the plug.

I did that and it popped the fuse?
I can put power to it though.

Thanks for the reply

[1stworks]

when you turn on the key, you will only have power for 15 seconds to prime the pump.
Then when you are in starting mode, it also has power.
And again while running.

Rich

Thanks Rich and yes i have those thing happen with my probe on the wire.
Where's the trigger come from?

With out probe iam missing something on that wire.
Idno but i read 1.7 ohm to ground on that red fuel pump wire........?????

Thanks
Scotty

[SirAndy]

Where's the trigger come from?
FI brain

With out probe iam missing something on that wire.
Ground


The way the fuel pump circuit works is that the FI brain switches the ground to run the pump.

The correct way to wire your relocated pump would be to simply extent both wires from that plug to your fuel pump up front and all should work just fine.

There was no need for the PO to even cut into the harness, all you need to do is get two wires with male ends and stick them into the female ends on the plug.

(IMG:style_emoticons/default/popcorn[1].gif)

[SirAndy]

There was no need for the PO to even cut into the harness, all you need to do is get two wires with male ends and stick them into the female ends on the plug.

Like dis:

(IMG:http://www.914world.com/specs/SirAndyCarbFuelPumpRelay_files/FuelPumpPlug.JPG)

[1stworks]

your probe must be acting like a ground, grounding the plug.

I did that and it popped the fuse?
I can put power to it though.

Thanks for the reply

Nice i put better ground to the other side of that plug and it runs!!!

Ill install nice ground there and tidy up wires..........

[1stworks]

Where's the trigger come from?
FI brain

With out probe iam missing something on that wire.
Ground


The way the fuel pump circuit works is that the FI brain switches the ground to run the pump.

The correct way to wire your relocated pump would be to simply extent both wires from that plug to your fuel pump up front and all should work just fine.

There was no need for the PO to even cut into the harness, all you need to do is get two wires with male ends and stick them into the female ends on the plug.

(IMG:style_emoticons/default/popcorn[1].gif)

Thank you!!!!!!!!!


I can fix wiring and make it nice.

[1stworks]

Where's the trigger come from?
FI brain

With out probe iam missing something on that wire.
Ground


The way the fuel pump circuit works is that the FI brain switches the ground to run the pump.

The correct way to wire your relocated pump would be to simply extent both wires from that plug to your fuel pump up front and all should work just fine.

There was no need for the PO to even cut into the harness, all you need to do is get two wires with male ends and stick them into the female ends on the plug.

(IMG:style_emoticons/default/popcorn[1].gif)

Whats weird is it ran fine without ground in that plug for 7000 miles that ive had it?



Thank you!!!!!!!!!


I can fix wiring and make it nice.

[SirAndy]

Whats weird is it ran fine without ground in that plug for 7000 miles that ive had it?

No, that's not weird. It's just wrong and dangerous.

Without the FI brain controlling the ground your high pressure FI fuel pump will run continuously while the key is ON.

You car will run fine. It will also spray fuel all over your car just fine if you ever have a leak and it will also burn your car to the ground just fine if that leak is near a hot spot or spark.
(IMG:style_emoticons/default/shades.gif)

[1stworks]

Whats weird is it ran fine without ground in that plug for 7000 miles that ive had it?

No, that's not weird. It's just wrong and dangerous.

Without the FI brain controlling the ground your high pressure FI fuel pump will run continuously while the key is ON.

You car will run fine. It will also spray fuel all over your car just fine if you ever have a leak and it will also burn your car to the ground just fine if that leak is near a hot spot or spark.
(IMG:style_emoticons/default/shades.gif)

It must have been controlling it bc i could hear the pump run than shut off.
There was never anything in the ground side.
Is it possible there's a ground spliced in somewhere?
Dont know till i find the fuel pump.Looks like its under the gas tank.


So i can run a small ground from plug to ground in engine compartment.
Whitch starts car and turn pump on and off property,or run 2 new wires power and ground directlyto pump......

Thanks again for help.
I dont want to start on fire.

[SirAndy]

It must have been controlling it bc i could hear the pump run than shut off.

Post a picture of your relay board ...
(IMG:style_emoticons/default/thisthreadisworthlesswithoutpics.gif)



In the pic below (NOTE: This is NOT what your relay board should look like!!!) where it reads "Wire replaces FI brain" your relay board should have a white plastic connector with 4 white wires.
If not, someone did even more hacking to your wiring harness ...

(IMG:http://www.914world.com/specs/SirAndyCarbFuelPumpRelay_files/FuelPumpWireEnable.jpg)

[1stworks]

(IMG:http://www.914world.com/bbs2/uploads_offsite/i1315.photobucket.com-15718-1384305209.1.jpg)

I really need to get to the fuel pump, sucks I have to pull tank........


Thanks for the help!!

[Dave_Darling]

The way the fuel pump circuit works is that the FI brain switches the ground to run the pump.

It grounds the FI power supply relay, but the relay sends power to the pump. The ground on the pump is a full-time ground.

--DD

[SirAndy]

It grounds the FI power supply relay, but the relay sends power to the pump. The ground on the pump is a full-time ground.

Crap, that explains that ... (IMG:style_emoticons/default/biggrin.gif)

I knew the brain was switching ground, but you are right, it switches ground on the relay, not the pump.

Doh!
(IMG:style_emoticons/default/headbang.gif)

[Dave_Darling]

Hey, you knew it was a ground that was being supplied! That's about 80% of the way there. (IMG:style_emoticons/default/biggrin.gif)

--DD

[1stworks]

Anyone know where that fuel pump relay is?

My plan is to run a new pair wires from the fuel pump plug direct to fuel pump?

Seams like a the proper fix?

Thanks!!!!