hey guys, this is the big weekend for my 350 install!!!

1985 350.
into a 1991 rs v8 305 700r4



but im at a jam with the harness,

I have cut the passenger side out, and removed the relays and c100
on the c100 i sepperated the wires and taped them all up,
I am trying to go off pockets diagram but it seems like there is missing stuff

like the wiper motor connectors
it just seems like I have alot more then he does

does anybody have or know where the is a diagram of what i need to install a carbed 350

please help I will install tomorrow

 

still need help only thing holding me back is-


from the fuel relay, where does the small red wire go? and the green with white line, go?

on the fan relay where does the green with white go?

the grey common between the c100 and relay go? is it just a ground?


small purple and yellow wire from the c100

 

I believe the red wire on fuel relay is the constant 12v to the relay - should be a hot-in-run wire - turn key to on and see if it has juice, then see if it has juice with key off.

Green/white should be the ground from the ECM that activates the relay. The ECM activates this ground for 2secs for the fuel pump priming.

I think this is right - it's been a long time since I did mine.

Since you are swapping to carb, and have cut the wires anyway - use the power from the Oil Pressure Sending Unit (OPSU) through the relay to run the fuel pump - this is what I did.

Your OPSU is located just above the oil filter - it has 3 wires to it. Cut the two larger wires - they should be orange and red. Now test each one - one has 12v the other has nothing. Now, run these to the relay on the power out side of the relay. Run a ground to the relay, and a hot-in-run wire.

What you want is:

turn key on, the hot-in-run wire "energizes" the relay, this connects the orange wire with the red wire, sending 12v to the fuel pump. turn key off, hot-in-run turns off, relay no longer energized, thus no power to the fuel pump.

Regardless of the relay, your engine will start and run. The OPSU senses oil pressure when car is cranked, and turns on the fuel pump as long as there is over like 3psi oil pressure.

BUT ... the OPSU can go bad, as has happened to me. This can either 1) make the fuel pump not run at all because the OPSU is not sensing the oil pressure, or 2) make the fuel pump run constantly regardless of the ignition key because the OPSU 'thinks' it's sensing oil pressure when there is none.

That's why I utilized the wires from the OPSU harness, and utilized the OEM fuel pump relay - that way my fuel pump will only ever run with the key on, and the there's only 2 pieces of the puzzle that can ever go bad - either the 10amp fuse tucked in the fenderwell behind the battery, or the relay - both of which are easily accessible at ANY auto parts store.

Hope that helps!

OH - fan relay - green/white wire should be the ground from the fan switch that activates the realy to turn the cooling fan on (again, I think - been awhile). I installed an aftermarket fan controller that's adjustable and so much better (IMO) than the factory fan switch - so I don't use that myself either.

Good Luck!

 

what about the grey commons where do they go?

 

Ok, lets start at the beginning

90-92 have the wiper controls in the light harness half of the C100. This half is untouched for any type of swap. If you have wipers on the engine side, you have a 89 or older harness

Your problems are just starting. Assuming you have the 90-92 dash harness, several functions wont work. Depending on the year, some gauge pins moved around. The only thing that really stayed consistent is the main power, IGN and tach wiring

Fuel relay red is the prime wire. Add 12v and the pump will engage regardless of the rest of the car
Dk grn/wht is 12v call wire from the ECM to engage the relay
Gray common is the fuel pump wire. If you're going mechanical it goes away, along with the rest of the pump relay wiring. When using an intank helper pump, all of the wiring is retained, only the dk grn/wht wire is moved to an IGN source so it runs continuously when the key is on

Fan relay dk grn/wht is grounded by the ECM to engage the fan(s). Use a toggle switch for manual control and/or a thermal switch for automatic control. Hard ground it to force the fans to engage with the IGN on. I wouldnt recommend this because the fan motors are not designed for continuous use and will burn out after a week or two

Ppl/yel wires are for the VSS. 90-92 TBI cars and older V6/TPI cars used them. They go directly to the buffer box. You need these to keep speedo function

 

i am using the pump in the tank does this change where the grey wire goes?


and just asking, how hard is it to change a tranny pump?

 

If using a pump, leave the wire and relay alone. Connect the dk grn wire to an IGN source and it will run when the switch is on