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Clayso
Clayso, Master Automobile Technician
Category: Cadillac
Satisfied Customers: 880
Experience:  ASE Master Certified Automobile Technician. 30 Years Experience.
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I have a 1991 Seville that won't start. The fuel rail is

Customer Question

I have a 1991 Seville that won't start. The fuel rail is under pressure, there is a strong spark, and the engine cranks fine. The fuel pump and filter we just replaced but the engine still won't start. Where should I look next?
Submitted: 1 year ago.
Category: Cadillac
Expert:  Clayso replied 1 year ago.

Hi Marvin, I'm Clay a certified master automobile technician with 30 years of automotive repair and diagnostic experience.

From your description most likely there is no injector pulse. See if the engine will run on carb spray. If the engine will run for a few seconds after spraying some carb spray into the the throttle body verify there is power on one of the terminals of any of the injectors. Injector fuses #5 & #6 power the injectors and the PCM pulses ground to the injectors.

You can check injector pulse at any of the injectors with a niod light plugged into the injector connector and spinning the engine. The niod light should flash when the engine is spinning over. If there is power to the injectors and no pulse, suspect a faulty PCM. Verify the powers and grounds to the PCM before replacing. If you need connector views for the PCM let me know.

I hope this information is helpful. If you have any questions or run into any problems let me know.

Kindly rate my assistance in a positive manner so I may have credit for helping you.
Positive ratings are greatly appreciated.
Thanks.

Customer: replied 1 year ago.
I would like any additional info that you can give me, Thanks!!
Expert:  Clayso replied 1 year ago.

Hi Marvin, you're welcome and thanks for getting back to me. I take it there was no injector pulse and there is power on one side of the injectors with the key on and the engine will run briefly on carb spray. The link below is 2 of the connector views for the PCM. Verify the highlighted powers and grounds to the PCM with the key on.

PCM A/B & C/D Connectors

If you have powers and grounds to the PCM and no injector pulse the PCM is most likely at fault.

Let me know how this works out for you.
Positive ratings are greatly appreciated.
Thanks.

Expert:  Clayso replied 1 year ago.

Hi Marvin, I'm following up on any progress with this repair. I hope the information I gave was helpful. If you have any questions or run into any problems let me know.

Kindly rate my assistance in a positive manner so I may have credit for helping you.
Positive ratings are greatly appreciated.
Thanks.