Okay guys i have a 1987 Iroc-z i just did a 305 TPI to 357 Carb and i pulled all of the wiring harness from the passenger side including the PCM and im trying to locate the fuel pump wire so i can rewire that to the ignition with a relay and be on my way. THIS IS THE LAST THING I NEED. Ive done everything else trust me. Everything having to do with lock-up, Throttle cable and TV cable geometry, correct Fuel pressure bypass regulator, fuel pressure gauge rewired with the correct distributor rewired, correct spark plug wire hook up 18436572. Ive got everything done besides this one thing...PLEASE HELP. Pictures would be best. I understand that some of the IROC-Z's are diffirent with wiring especially with different size engines and different voltages going different places. I just turned 19 im going into the automotive field so be nice...yes i do not know everything. But please help...much appreciated. ~Nick~

 

AustinThirdGen has wiring diagrams.

Here is the one for 87 TPI with the fuel pump relay highlighted.
- The relay is under the hood, driver side, on the firewall, next to the brake booster. The other two relays are for MAF and MAF burnoff... which you can remove with the rest of the EFI.
- Make sure you didn't cut the orange wire (power supply) along with your other purge.
- The dark green/white wire activates the relay, which turns on the pump.
- The tan/white wire (also) goes to an oil pressure switch, typically screwed in to the block just above the oil filter. (Or, could be at the China rail, next to the distributor).

 

THANK YOU SO MUCH I CANNOT HONESTLY THANK YOU ENOUGH. Ill let you know if i run into any problems

 

Wait....lol. I removed that with the passenger side harness and i cant find the wire thats under the dash on the passenger side that it connected to. How would i rewire this since that relay is removed with the ECM? Im confused at this point.

 

Found a connector back by the fuel tank that seems to be running from the fuel pump its a pink/something color and other wire is a gray wire. Can i run this straight to the ignition with a fusable link and power the fuel pump?

 

Finding all the parts and connecting them front to back, and back to front is a good way to learn, and make sure you have everything, and did it right.

Don't be THAT guy. This is NOT the right way. And, if you hack your wiring into god knows what, NO ONE will be able to help you.

The fuel pump wire goes from the inside of the car to under the car directly between the rear seats. Follow that wire to the drivers side door sill, to the firewall.

Now, for the harness that you've removed... Remove the plastic looms, and get ready to cut the plastic wrap.
* Find the relay (hint, it has 5 wires. The other two only have 4 wires).
* Extract all of the wires from the harness that are attached to the relay.
You will have to cut a few wires, but make REALLY, REALLY sure you won't need that wire before chopping it up. Let's start WITH the orange one...
- take the MAF burnoff relay, follow the TWO orange wires to the junction, and cut there.
- next, take the MAF relay, follow it's single orange wire to the junction and cut there.
- there are two wires running to the ECM...B1 and C16. Cut those from the junction... MAKING SURE you are not also cutting off the fused feed wire... keep that.

That orange wire should run from the FP relay, to the oil pressure switch, and to the fuse panel.

Dark green/white. Follow this from the relay, and cut the wire as close to the ECM as possible. This gives you the most option as to where you will be able to join it in the the appropriate circuit.

 

Okay forgive my ignorance i forgot to state that wiring is currently my weak point. But what i believe your saying is trace that fuel pump wire i found from the back (FP power wire?) and after stripping down the harness properly im going to re insert the fuel pump relay attach it to the power wire and run it into the fuse box properly (somewhere that is powered when the key is on)?

 

Here are the 2 wiring schematics from the 87 shop manual for a TPI car; they are a little easier to read than black and white diagram. ( you don't really need to see the second one - it only shows where the ground wire goes. )





For a Carb fuel system I would use a block mounted mechanical pump - but if staying with an electric pump is the direction you are taking; Install a relay somewhere and wire it exactly as shown in the diagrams. Like MoeJoe said - don't just wire the pump to an ignition wire.......... Use a Relay !!

P.S. If the original TPI harness is still fully intact I wouldn't hack it up just for a single stupid relay. Just post an add in the classifieds - I'm pretty sure someone will be able to help. ( Hell - every parts store should have a 5-pole relay on the shelf; I used a 4th gen FP relay for my TPI fuel pump ) IMO it's better to keep it fully intact and sell it to someone that could use it,... then use the $$ you bring in to continue your IROC build.

Hope this helps !

 

Everyone has to start somewhere. Just don't get too impatient and start hacking away.

Now you've made me pull out my Service Manual and look this up...
ETA: Thanks, John, for posting pictures of the manual pages I was reading. The harness may be valuable, un-cut, to someone else. Or, you (OP Nick) can use as much of the factory parts as possible, since it is "free" to you, you don't have to go buy new parts to re-create the factory parts you already have, and will keep as much factory as possible... reliable, and can be troubleshot by anyone with a manual.

Cxxx are the factory "C"onnectors or plugs.
C207 is a 15 cavity (spaces for wires) plug inside the car, near the ECM (right side, passenger foot area).
C208 is also 15 cavities, left side, behind the driver's kick panel.
C304 is between the rear seats.

- The fuse is a weather pack connector near the battery. Orange/Black on the battery side, and the Orange wire leads to the:

• fuel pump / oil pressure switch (keep)
• FP relay (keep)
• 2x ECM (cut)
• MAF and MAF burnoff relays (cut)

- the brown/white wire connects between:

• FP / oil pressure switch... with the orange wire. (keep)
• FP relay (keep)
• ECM (cut)
• MAF relay (cut)
• C207 (keep)... this runs from the relay/switch across the engine harness, toward the ECM connectors, and leads to the FP itself. On the other side of C207 is a brown wire, which runs across the dash to C208, which changes to a tan wire and runs back to C313.

- Orange wire from the relay (cavity D) also goes to C207, changes to a red/black wire, and on to the ALDL. You don't really need this, but it is still built in to the dash harness, and it may be useful.

You should be able to trace the wiring from the battery to the relay, and all the way to the fuel pump. By using as much of the factory wiring as-is, it will already be connected. Since you are removing the ECM, which controls the initial signal to turn on the relay/pump, you will have to figure out where to tie in... you need a circuit that is hot in Run and Start... I'm thinking the pink wire that goes to the distributor.

 

Lots of good info