Why does the fuel pump continue to run on my 88 5.7 tpi after engine is shut off? I've change relay, pump even continues to run after fuse by battery is pulled or relay is pulled from socket.

 

First of all, how long does it run for once you have the ignition off? It WILL run for a couple seconds once you stop cranking the engine, but it should turn completely off if the key is OUT of the ignition.

If it continually runs, it sounds as if you have a problem with the relay, but you've already said you pulled the relay, and it still runs.

Don't take this the wrong way, but make sure you've identified the correct relay. It's hard to do the "Click Check" by having someone turn the key to the run position while you have your hand on the relay feeling for the "Click--2 second pause--Click" characteristic of the fuel pump relay if it has failed in the energized position.

Try dis-connecting the other three relays that are in the engine bay cluster on the drivers side firewall and see what happens.

Steve

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86' Trans Am WS6, Black with tinted windows, GTA rims, Shaved door handles, ZZ4 crate engine, TPIS Mini-ram, 23lb/hr injectors, 52mm throttle body With airfoil, AFPR, Custom speed density harness with 93' computer and Level-6 PROM, Accel 300+ with 300+ spiral wound wires and Bosch platinums, Custom dual snorkel K&N, PST suspension products, Hotchkis springs, Hooker 1 3/4" Super comps, True duals with supertraps and no cats, Art Carr 700R4 with 2400 stall converter, B&M Mega Shifter, Mobil 1 synthetic front and rear, lotsa other stuff.
SOON: AFR 190's and LT4 Hot Cam.

 

i have the same prob...

 

I have an '88 305 TBI that does the same thing. It runs until the battery is dead. mechanic replaced switches and relays and it still runs...