NickDoh

i have an 88 trans am gta and i have a couple questions;

where is the fuel pump relay?

and

what voltages should i be getting from the wires going to the fuel tank? theres a black wire, pink wire, and a tan wire with a stripe. which is which?

any help is appreciated.

bronson_91

On my 92 Z28, the fuel pump relay was located on the driver's side of the firewall, in the engine compartment, next to the two fan relays. I could hear the coil click (energize) as the computer was priming the injectors, when the key was turned to the ON position, but before START.

Also, on the wiring diagram for the Z, I'm showing the tan wire (no stripe) as power to the pump (comes from the oil presssure switch, which is what keeps the pump on once the engine is running). ONe of the remaining wires has to be the sender, while the other is a ground I suspect. So, on the tan wire (or one wire, if the TA differs), you should get +12V when the oil pressure switch closes (i.e., there is oil pressure). So you'd have to figure a way to bypass the switch (like use a jumper wire across the terminals) in order to get 12V on that wire. Conversely, you can turn the ignition to on, and you should get 12V momentarily, as the computer primes the injectors.

You will get no voltage on the sender wire (or at least no reading that would be relevant). Instead, in order to find which is the sender wire, set the multimeter to read resistance. If there is some gas in the tank, the reading should be between 0 and 90 ohms (measuring from the wire to a good ground).

The third wire will obviously show very little resistance (under 1 ohm) when measuring from it to a ground, irrespective of how much gas there is in the tank.

BigBadLou

iTrader: (3)

The sender wire is pink, irrelevant voltage.
The ground wire is black (most ground wires on our cars are black).
The power wire to the pump is tan/white.

Lou