I can't find any reference in my 1988 Fiero Service Manual as to where the wiring to the fuel pump is routed. I've ended up with one black and one grey wire tagged "A2" and "B2" hanging off the 3.4 DOHC wiring harness. I am assuming these were the power and ground connections for the fuel pump on the 1992 Lumina.

Are the Fiero pump connections inside the passenger compartment somewhere? If so, do I just eliminate the Lumina connections from the harness?





Thanks

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1988 GT, 5-speed, white, beechwood leather, 3.4 DOHC installation in process.

Found an old post of yours that says you are using the 16149396 ecm. If that is tru then according to my doc A2 goes to one of the IAC pins (C102 pin J on the 3.4's engine sub harness, that's the black 10 way connector). B2 is not connected to anything.

On your fiero wiring diagram, bottom right by the fuel pump it says 3-way connector. I believe that C502 (well it is on mine but mine was an 85 4 cyl so your milage my vary), anyway assuming the numbers are the same I 'think' that's down on the lower firewall somewhere (my book says center of rear firewall).

For C502:
A goes to earth. Its the earth for both the pump and the fuel gauge.
B comes from the fuel gauge, other side of gauge in i/p goes to batt +ve.
C is the fule pump +ve supply it connect to C203 (clear connectors under center console) pin L (car side)

The engine side of C203 Pin L goes to:

ECM Pin A20
Fuel pump relay pin B
Oil pressure switch pin C

Hope that helps some.

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Dave E

www.ltlfrari.com

Roger on the 9693. If you look at the 3.4DOHC diagram, at the bottom where the pump is shown there is a connector on each side, A2 and B2. All of the wiring connections are done except these. I'm going to assume those two connections are already in place on the Fiero.

Thanks again.

[This message has been edited by sspeedstreet (edited 07-03-2006).]

Ah, I see what you mean now (been a loong day !!).

Well at some point you must have power going to the fieros pump via C203 pin L and C502 pin C so you must have spliced into there somehow. Ditto for the earth.
If that's the case then A2 & B2 would have been to take power from the sharp end to the tank up back and on that basis, yes you could just tape them up.
But I'd still like to know how you are getting power to the pump.

The fuel pump connector itself in chassis-side of the C500 on the Fiero (i.e. with the engine wiring removed it'll still be on the car!). You'll find it in the engine bay along the firewall. The power goes to it through pin L on the C203. When the fuel pump relay control wire from the ECM or clutch switch is hot the fuel pump relay will provide 12v+ to C203 L.
The ground for the pump itself is built into the body-side connector. The fuel pump relay DOES need to have ground though! Make sure it does..

In other words, your gray wire has to go to C203 L, pin C of the oil pressure switch, and pin 3 on the fuel pump relay. The fuel pump relay ground, the black wire from pin 2, needs to be grounded. The fuel pump itself gets ground through a pin the Fiero's fuel pump connector, so don't worry about that.

[This message has been edited by Steven Snyder (edited 07-04-2006).]

OK, I finally found the C502 connector on the firewall. Oddly enough, it's right next to the tank vent line (duh!). Aces to you both.

Yup, just make sure that little guy is plugged in and you've got 12v+ on C203 L and the pump should run.