I have a 1988 Camaro with a 5.0L TBI engine and a 5-speed transmission. When I try to start the car it will take 4 to 5 times cranking it before it will start. When I first turn the key on I can not hear the fuel pump running and also the ignition key is very loose in the steering column. I checked the voltage at the fuel pump relay with just the key on and there is no voltage, you can watch the meter and on the 4th to 5th time trying to crank the engine you will see the meter go to 12 volts and the car will start. What is controlling the voltage to the fuel pump relay? The key switch? The Computer? Both, I’m lost at this point what could be wrong?

 

semcx,

Welcome to ThirdGen.org!

The fuel pump is controlled by the ECM at start up. The ECM gets its signal from the ignition circuit. So, in effect, both the ignition switch and ECM control the fuel pump. There is also an auxilliary oil pressure switch that provides power to the pump circuit once the engine is cranking or running.

The ignition switch is nowhere near the lock cylinder. It is located near the bottom of the steering column and is connected to the key cylinder via a linkage rod. If the voltmeter and indicator lamps do not operate when you first turn on the ignition, you may well have an ignition switch problem. If the indicator lamps and voltmeter operate, the fuel pump power relay should operate for two seconds to prime the fuel rails.

 

Hello, yes when the key is turned on the lights and gauges on the dash do light up but the fuel pump will not turn on. Thanks

 

This is the circuit:



The ignition switch supplies power to the ECM. The ECM perfoms a self test for about 1.2 seconds, then supplies power to the fuel pump relay for two seconds. You should be able to hear the pump running in those first two seconds. The ECM will again operate the pump relay for two seconds as soon as the engine is cranked and distributor reference pulses are generated, or if the ignition is turned off for at least 20 seconds and then turned on again. The pump relay must have reliable connections and good contats. The ECM/Fuel pump fuse must be intact. In your case, teh fuse is probably good since the "Check Engine" lamp turns on with the ignition. That power must still be routed to the pump relay, so again, connections are critical. Since the engine does eventually start, I'd presume that the wiring to the pump itself is intact. Check the relay. If your ignition switch is "loose", I'd plan on investigating that as well, before it leaves you stranded.