Engine cranks, sputters, backfires, no start

2005 JEEP GRAND CHEROKEE
257,000 MILES • 3.7L • 6 CYL • 4WD • AUTOMATIC
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
When i turn the key engine crank tries to start sputters then backfires no start.
Jan 6, 2021 at 12:03 AM
Advertisement
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Good morning,

I would start with a compression test to be sure the timing chain has not failed. Backfiring usually has to do with timing.

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

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/how-a-timing-belt-works

Roy
Jan 6, 2021 at 12:36 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
I would but vehicle does not start as mentioned above.
Jan 6, 2021 at 3:32 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
The vehicle was running before but when it got hot i would get traction not enable and vehicle would just shake. turn it off wait then restart engine light flashes 10 times.
Put on scanner code for crankshaft replace and replaced plugs.
Clear codes rescan code comes up for camshaft. replaced now no codes.
Jan 6, 2021 at 3:51 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
It does not need to run for a compression test at all. It is done by cranking only.

The fact you have cam and crank sensor codes tells me it may be timing.

Roy
Jan 6, 2021 at 4:16 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
The cam sensor came up when i took it out by accident and when i put in old one that's when the code came up. the wire was not connected tight so i reconnected after no codes and would i have not notice if timing was off.
Jan 6, 2021 at 4:53 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Let me know the results of the compression test.

Roy
Jan 6, 2021 at 4:59 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
Also video for checking timing and compression is not available.
Jan 6, 2021 at 5:04 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
You can rent a tester at a parts store and the guide I sent you shows you how to perform the test.

Roy
Jan 6, 2021 at 5:10 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
I am in Canada and not sure if they rent tools here. but you said if i just want you to know if i had compression by using paper towel.
Also if timing is off how is this fixed? Also the engine lights flashes 10 times.
Jan 6, 2021 at 5:38 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
You need a gauge to test. You need 140-160 pounds in each cylinder. The paper towel is not a valid test.

If it is off, then the front of the motor has to be torn down to find out what failed in the timing system.

I attached a youtube video of the procedure for you to follow.

https://www.youtube.com/watch?v=0bHxW0qU4WQ&t=4s

Roy
Jan 6, 2021 at 5:46 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
If that the issue then what's the next step?
Jan 6, 2021 at 6:08 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
If the compression is low, then you need to insert shop air into each cylinder that is low to see where the compression leak is located.

It will either come out the exhaust, the air filter, or the oil fill cap.

You need to determine this prior to tearing down the motor.

Roy
Jan 6, 2021 at 6:17 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
No if there is no compression issue what's next?
Jan 6, 2021 at 6:30 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
As I stated in my last response, shop air is inserted into the cylinders to determine where the compression leak is located.

Roy
Jan 6, 2021 at 6:43 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
I will reword it if the compression is okay, what would be the step?
Jan 6, 2021 at 8:57 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
One step at a time. Keep me updated on the compression test.


Roy
Jan 6, 2021 at 9:01 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
Cannot rent tools COVID. any other way to test?
Jan 7, 2021 at 1:41 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Nope, you need to buy a cheap one. Do you have any Harbor Freights around you? They have some cheap test equipment.

Roy
Jan 7, 2021 at 1:53 AM
Avatar
JOHN CLARK8
  • MEMBER
  • 17 POSTS
No, i am in Ontario Canada lock down until 28th.
Jan 7, 2021 at 2:37 AM
Avatar
ASEMASTER6371
  • Experienced Mechanic
  • 52,796 POSTS
Okay, you will have to wait until you can get the tool.

Roy
Jan 7, 2021 at 2:49 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.