Car will not stay on

Tiny
LORTEGA
  • MEMBER
  • 2003 CADILLAC CTS
  • 147,781 MILES
Did a tune up. Replace both coil packs. Car started up once took for test drive. Came to stop car shut off.
Now it won't start. Smell fuel when trying to start.
So I decided to check fuel pump relay. I take it out car starts. Plug it back in car won't start.
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Friday, June 7th, 2019 AT 5:02 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Welcome to 2CarPros.

If the car starts with the fuel pump relay removed, my first suspect is the fuel pressure regulator is allowing the fuel pump to build too much pressure and basically flooding the engine. Chances are that is why you smelled fuel.

Before replacing the regulator, you really should confirm that the pressure is too high. Here is a link that explains how to check fuel pressure and the fuel pressure regulator:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here are the manufacturer's specifications for fuel pressure:

Fuel Pressure (Key ON Engine OFF) .................... 337-379 kPa (49-55 psi)

If you determine the regulator is bad and allowing too much pressure to the fuel injectors, here are the directions for replacing it. The attached pictures correlate with the directions.

___________________________________________________

PROCEDURES
REMOVAL PROCEDURE
1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure.

CAUTION: Refer to Gasoline/Gasoline Vapors Caution in Service Precautions.

2. Remove the air inlet grill in order to gain access to the fuel pressure regulator.
3. Place a shop towel under the fuel pressure regulator to absorb any lost fuel when removing the regulator.
4. Disconnect the atmospheric vent hose from the fuel pressure regulator.

pic 1

5. Remove the fuel pressure regulator clamp bolt.
6. Spread the clamp only enough to allow the fuel pressure regulator to be removed.

pic 2

7. Twist while pulling outward in order to remove the fuel pressure regulator from the fuel rail.

INSTALLATION PROCEDURE

pic 3

1. Apply a few drops of clean engine oil to the O-ring seals on the fuel pressure regulator.
2. Twist while pushing inward on the fuel pressure regulator, until fully seated against the fuel rail.

IMPORTANT: Be sure to locate the atmospheric vent toward the front of the engine on the fuel pressure regulator.

3. Position the clamp around both the fuel pressure regulator and the fuel rail.

pic 4

4. Install the fuel pressure regulator clamp bolt.

NOTE: Refer to Fastener Notice in Service Precautions.

Tighten
Tighten the fuel pressure regulator clamp bolt to 5 N.m (44 lb in).

5. Install the atmospheric vent hose on to the fuel pressure regulator port.
6. Using the scan tool turn ON the fuel pump to pressurize the system.
7. Check for fuel leaks.
8. Install the air inlet grill.

__________________________________

Let me know if this helps and what you find. If you have other questions, let me know.

Joe
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Friday, June 7th, 2019 AT 10:00 PM
Tiny
MICHAELSMITHCA
  • MEMBER
It is very strange that after pulling fuel pump relay back it is not working. The possible reason in my mind is that the car engine got some damage while riding, that's the only reason I can see.
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Saturday, June 8th, 2019 AT 3:48 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Welcome back:

When you reinstall the relay, the fuel pump isn't working? If that's the case, I need you to first check the relay and make sure there is power to the relay.

Here are a few links to help:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

___________________________

Also, I need you to check some fuses for me. I attached pictures for you to help locate the ones I'm questioning. One is in the under hood fuse box and the others are in the right rear fuse box. Here are a couple links to help:

https://www.2carpros.com/articles/how-a-car-fuse-works

https://www.2carpros.com/articles/how-to-check-a-car-fuse

I think I would start by checking fuses to see if any blew. If they are all good, check the relay as indicated above.

Let me know what you find. I doubt there is engine damage. Based on your original description, it sounds more like a fuel pressure regulator issue.

Take care and I'll watch for your reply.

Joe
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Saturday, June 8th, 2019 AT 9:15 PM

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