I didn't get to doing it this weekend but I would like to double check that it will be done correctly. I drew a diagram following Darth's instructions below but I am still not sure where the C203 connects in. Also for the oil sending unit I want to double check that I just cut the tan wire coming out from the sender.

Depends on what you are doing this for, swapped motor or 2.8 / 3.4 Fiero motor?

For a 3800, all you have to do is the picture of the relay and that looks correct since you have added the fuse and the additional ground... Clear out the upper left picture of cutting the Oil Pressure Sender wire. I assume that c203 is if you are using a more powerful fuel pump with like a 3.4 swap and using the stock Fiero wiring...
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-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel
My HUD install thread
Modified stock air canister and base to 3.5 inch for 3800na

Isn't it strange that after a bombing, everyone blames the bomber, his upbringing, his environment, his culture, his mental state but … after a shooting, the problem is the gun?

[This message has been edited by MulletproofMonk (edited 10-23-2013).]

quote Originally posted by hinesb1890: I didn't get to doing it this weekend but I would like to double check that it will be done correctly. I drew a diagram following Darth's instructions below but I am still not sure where the C203 connects in. Also for the oil sending unit I want to double check that I just cut the tan wire coming out from the sender.

Your diagram looks correct. Now all you need to do is to connect the ECM/PCM's fuel pump relay output wire (green/wht) to the tan/wht wire going thru pin L of the Fiero's C203 connector. You need to hook it up so the ECM/PCM can power up the tan/wht wire going out thru the Fiero chassis wiring harness (not the original Fiero ECM harness).

-ryan

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OVERKILL IS UNDERRATED

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

quote Originally posted by Darth Fiero: Your diagram looks correct. Now all you need to do is to connect the ECM/PCM's fuel pump relay output wire (green/wht) to the tan/wht wire going thru pin L of the Fiero's C203 connector. You need to hook it up so the ECM/PCM can power up the tan/wht wire going out thru the Fiero chassis wiring harness (not the original Fiero ECM harness). -ryan

So I just add a cross wire tapped into both? And I do or I don't cut the tan oil pressure sender wire?

quote Originally posted by hinesb1890: So I just add a cross wire tapped into both? And I do or I don't cut the tan oil pressure sender wire?

The tan/wht wire that comes from the C203 connector and goes into the OE Fiero ECM harness travels out to the stock Fiero fuel pump relay and oil pressure sending unit. You can cut this wire inside the car and just wire the ECM up to the end that goes thru the C203 connector and into the chassis wiring harness. Doing this means you don't have to cut the tan/wht wire at the oil pressure sending unit.

The oil pressure sending unit has 3 wires. Orange, Tan, and Tan/wht. The TAN wire that comes out from the center terminal is for the oil pressure gauge on the dash. DO NOT cut this wire.

The Orange wire is 12v + battery power from the F.Pump fuse which is shared with the OE Fiero fuel pump relay via C203 terminal B. After you perform the hot wire fuel pump mod, you can just remove the F.Pump fuse from the fusebox if you aren't going to need power on this circuit for anything else since it will no longer be needed with the hot-wire fuel pump mod.

[This message has been edited by Darth Fiero (edited 10-24-2013).]

Ok thanks, I still find it hard to understand though without directly looking at it. Do you have a picture or can you draw up a really simple diagram? Wiring is just not my expertise which is why I bought everything plug and play.