Backfires and will not run

Tiny
GORD DION
  • MEMBER
  • 2007 SATURN AURA
  • 3.6L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
Was running rough, got code for injector on bank1. Replaced Injector and car ran fine. The next morning it wouldn't start. Finally started ran rough then died. Showed code for Crankshaft Position Sensor. Replaced sensor and started but ran like it was flooded the backfired and died. Now it won't start. Suggestions?
Tuesday, January 11th, 2022 AT 7:41 AM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

If the vehicle won't start, in most cases it is related to either a spark or fuel issue. Try this: See if the engine starts using starting fluid and then stalls. If it does, then we know it's a fuel-related issue. If it still fails to start, I need you to check for spark to the plugs. Here is a link that explains how that is done.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If you find there is spark to the plugs, remove a few spark plugs and see if they are wet with fuel. The fuel pressure regulator may have failed, allowing too much pressure to reach the injectors. If wet, check fuel pressure. Here is a link showing how it's done:

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

Let me know what you find.

Take care,

Joe
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Saturday, January 15th, 2022 AT 4:59 PM
Tiny
GORD DION
  • MEMBER
  • 9 POSTS
Thanks Joe, one correction on my part, it wasn't an injector. It was a fault code for an ignition coil in Bank 1. Replaced the coil and the car ran perfectly. The next morning it wouldn't run well and backfired then died. Then it gave a code for the crankshaft position sensor. Replaced it and it barely started and backfired. Then it gave the codes for all the camshaft sensors and said advanced timing. That's where I'm at now. Could it be that the computer needs to be flashed? Or is it more likely it has skipped a tooth on the timing chain? Any help will be greatly appreciated. Thanks, Gord.
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Sunday, January 16th, 2022 AT 4:34 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

The 3.6L has a timing chain, so in most cases (not all) it doesn't jump. However, if it is backfiring, it may have. Take a look through this link and let me know your thoughts.

https://www.2carpros.com/articles/engine-backfires-while-running

Hang in there. We'll get it figured out. If possible, record it cranking and upload it for me to hear. Also, let me know specifically what codes you are getting.

Take care,

Joe

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Sunday, January 16th, 2022 AT 6:50 PM
Tiny
GORD DION
  • MEMBER
  • 9 POSTS
Hi Joe,

This car is becoming a nightmare. At this point, I'm a spectator, my cousin and his son (who is a mechanic) have taken over. They replaced the timing chains and gears and retimed everything yesterday and the car started and ran fine. Today it is misfiring again. Any suggestions?
Thanks, Gord
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Tuesday, January 25th, 2022 AT 7:49 PM
Tiny
GORD DION
  • MEMBER
  • 9 POSTS
Also, it isn't giving any codes for why it is running so bad. A friend that is a GM mechanic said to start replacing parts like ignition coils, spark plugs etc. Sounds like an expensive way to find the problem.
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Tuesday, January 25th, 2022 AT 7:54 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If there are no codes, has anyone checked the short-term fuel trims, the coolant temperature sensor signal, and fuel pressure?

Let me know. If they have, let me know what they found. If they haven't, ask if they could check them and let me know what they are.

Joe
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Tuesday, January 25th, 2022 AT 9:04 PM
Tiny
GORD DION
  • MEMBER
  • 9 POSTS
According to my cousin, the scanner indicated all sensors normal and fuel system normal. He also said that the problem starts when the engine warms up. When the engine is cold it runs good, but as soon as it changes and the fast idle drops to low idle is when it starts misfiring and the scanner says misfire. It did give the P0300 code, but no accompanying codes.
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Wednesday, January 26th, 2022 AT 7:47 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

The idea that it runs normally until it warms up points me in a couple of directions. First, a faulty coolant temperature sensor. Second, a fuel pressure issue. And third, a possible issue with the crankshaft position sensor (CKP).

When starting to fail, the CKP can cause the vehicle to stall, misfire, and even not restart until it cools off. Interestingly, the sensor may or may not set a trouble code/CEL.

Take a look through this link that explains symptoms related to a failing CKP. See if you feel it mirrors what you experience.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

As far as the fuel trims, I would think that would change when warm. By chance, could you ask him again for the short-term fuel trims when warm?

Let me know.

Joe
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Wednesday, January 26th, 2022 AT 4:12 PM
Tiny
GORD DION
  • MEMBER
  • 9 POSTS
Hi Joe, this car is insane. We checked the spark plugs and they were black. They had just been replaced when this problem started. We installed six new spark plugs again. Next, we replaced the Ignition coils. Cleared the codes and started the car. Now it's not misfiring but it is running very rough. All previous codes are gone and now it says 07EA. That I believe means the Mass Air Flow Sensor. That is the only code. Something is causing the computer to keep throwing different codes, none of which makes sense. Can cleaning correct this problem? What should we use?
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Wednesday, February 2nd, 2022 AT 4:52 PM
Tiny
GORD DION
  • MEMBER
  • 9 POSTS
Hi Joe, I'm becoming very suspicious of the computer. Could it be a poor and or dirty connections on the computer?
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Wednesday, February 2nd, 2022 AT 4:56 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

You are correct. The code deals with the MAF. Do me a favor. Disconnect it and see if it runs differently (better). By disconnecting it, it should go into a preset mode and run a little better. The idea that the plugs were black indicates it's getting too much fuel, and the MAF can be causing issues. If the sensor is providing a faulty signal, it will cause fuel issues.

If you want to try cleaning it, here is a link that shows how it's done:

https://www.2carpros.com/articles/mass-air-flow-service

Let me know what happens with it disconnected.

Take care,

Joe
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Wednesday, February 2nd, 2022 AT 8:13 PM

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