Fuel Injector Help

[CUBBY782005]

Have A 1988 Buick Century Lost Fire Fixed That Now Injectors Wont Fire . Will Run If I Spray Starting Fluid In Intake Replaced All Relays And Ecm And Coilpacks Any Ideas How To Fix Prob Or What Prob Is Also Replaced Fuel Pump

[maxwedge]

Welcome to AF, first, what engine?

[CUBBY782005]

It Is A 2.8 Liter Sorry Duh Important Info But Since The Post I Have Also Replaced The Crankshaft Sensor On Advice From Friend At Local Garage

[jdl]

Originally Posted by CUBBY782005

It Is A 2.8 Liter Sorry Duh Important Info But Since The Post I Have Also Replaced The Crankshaft Sensor On Advice From Friend At Local Garage

When the engine is cranking, is there an injector pulse?

I believe under a certain rpm the ignition module controls the spark. It is possible for the ignition module to see a signal and the computer doesn't. If the computer doesn't see an rpm signal, the injectors won't pulse.

There should be a purple wire with a white tracer going from the ignition module to the computer, with the engine cranking, there should be a signal on that wire. No signal and the injectors won't pulse.

There should be an oil pressure switch in the fuel pump circuit. Even if the relay is faulty, once you crank it enough to build oil pressure, the pump should run. You should have fuel pressure?

[CUBBY782005]

Originally Posted by jdl

When the engine is cranking, is there an injector pulse?

I believe under a certain rpm the ignition module controls the spark. It is possible for the ignition module to see a signal and the computer doesn't. If the computer doesn't see an rpm signal, the injectors won't pulse.

There should be a purple wire with a white tracer going from the ignition module to the computer, with the engine cranking, there should be a signal on that wire. No signal and the injectors won't pulse.

There should be an oil pressure switch in the fuel pump circuit. Even if the relay is faulty, once you crank it enough to build oil pressure, the pump should run. You should have fuel pressure?

HOW DO I TEST TO SEE IF PURPLE WIRE HAS SIGNAL?

[jdl]

Originally Posted by CUBBY782005

HOW DO I TEST TO SEE IF PURPLE WIRE HAS SIGNAL?

If you have a DMM that has a tach--dwell or frequency setting, any of these will react to a dc pulse. I believe a digital logic probe will also react to a pulse.

If you have a scanner, you can crank the engine and look for the rpm readout.

If you wanted to test an injector, you could use a noid lite on the injector plug, crank the engine, the lite should flash, if the computer is pulsing the injector. Sometimes you can lay your finger on the injector, with the engine cranking, and feel a vibration. You might be able to hear it click or buzz.

[maxwedge]

Originally Posted by CUBBY782005

Have A 1988 Buick Century Lost Fire Fixed That Now Injectors Wont Fire . Will Run If I Spray Starting Fluid In Intake Replaced All Relays And Ecm And Coilpacks Any Ideas How To Fix Prob Or What Prob Is Also Replaced Fuel Pump

Make sure you check the pcm/injector fuses.