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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15133
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Replaced fuel pump, fuel pump relay. Ignition module and

Customer Question

Replaced fuel pump, fuel pump relay. Ignition module and injectors still not getting fuel why
Submitted: 1 month ago.
Category: Chevy
Expert:  Jared D replied 1 month ago.

Good morning,

When you turn the key to on does the check engine light come on?

Customer: replied 1 month ago.
No check engine light
Expert:  Jared D replied 1 month ago.

It sounds like you have a bad ignition control module. It controls whether the fuel pump will run when the key is on and whenever we see these trucks come in with no check engine light illumination we change the ignition module right away.

I need to step out into the shop for a minute. I'll be back.

Customer: replied 1 month ago.
I have changed the ignition module already and still same issue
Expert:  Jared D replied 1 month ago.

I'm sorry, what I thought was a quick job turned into an all morning thing. Have you checked to make sure that you are getting power and ground at the ignition module?

Expert:  Jared D replied 1 month ago.

Are you getting power at the fuel pump relay? You should have power on the black/white wire and power from the PCM on the green/white wire at the relay.

Customer: replied 1 month ago.
have power
Expert:  Jared D replied 1 month ago.

So you are getting power to the relay from the PCM but not to the pump?

Customer: replied 1 month ago.
I'm not getting power to the injectors. Could it be the computer?
Expert:  Jared D replied 1 month ago.

1. Perform scratch tests using a conventional bulb type test light connected to B+.

2. Disconnect the 4-terminal connector at the distributor.

3. Turn the key on.

4. Touch the test light to the Purple/White wire and check for an injector pulse.

5. If no injector pulse, repeat this test at the Powertrain Control Module (PCM) and verify that the PCM is powered and grounded properly, and check for engine RPM on the scan tool when cranking.

6. If injector pulse is generated, reconnect the distributor and remove the distributor cap.

7. Touch the test light used in step 4 to the Green wire of the pickup coil attached to the ignition control module at the terminal labeled "P" with the key on.

8. Check for injector pulse and spark.

9. If OK on both spark and injector pulse, connect a Digital Volt Ohm Meter (DVOM) set to AC volts to the Green and White wire of the pickup coil and crank the engine.

10. If voltage is less than 0.7 V AC, replace the distributor shaft and pickup coil.

11. If no spark is generated during step #7, Verify the ignition coil has good power supply. Connect a test light across the White wire (coil trigger) and the Pink (coil power) and repeat step #7. If the test light blinks, replace the coil.

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